INTERNATIONAL RESEARCH TRAINING GROUP

8th Joint Symposium

Weiskirchen

September 2-4, 2019

2

Compendium

Monday, 09/02/19 Tuesday, 09/03/19 Wednesday, 09/04/19

Arrival

Registration Welcome

8:00 Breakfast 8:00 Breakfast

9:00 G. Khandpur 9:00 M. Schöppe

10:00 A. Khan 9:20 J. Oestreicher 9:20 M. Saurette

10:15 J. Bak 9:40 E. Zöller 9:40 C. Martins Rodrigues

10:30 A. Russo 10:00 J. Laborenz 10:00 K. Badior

10:45 Coffee break 10:20 Coffee break 10:20 Coffee break

11:00 M. Sicking 10:45 T. Bentrcia 10:45 K. Ravichandran

11:15 R. Brassard 11:00 M. Beggs 11:05 P. Schepsky

11:30 N. Yadao 11:15 X. Liu 11:25 Concluding remarks

11:50 F. Wollweber 11:35 Poster flash talks 11:35 PI & Trainee Meetings

12:10 Lunch 12:30 Lunch 12:00 Lunch

13:15 -

22:00

Visit of the “Saarschleife”

&

Saarburg “Saarweinfest”

13:30 Hike

End of Meeting

&

Departure

16:00 Poster Session

18:00 Guidance Committee

Meetings

19:00 Barbecue

10 min talk & 5 min discussion

15 min talk & 5 min discussion

Poster flash talks max. 3 min

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Day One (Monday, September 2, 2019)

Arrival and Registration until 9.45 am 09:55-10:00 Ekkehard Neuhaus Welcome

Session 1 (Chair: Gurleen Khandpur)

10:00-10:15 Azkia Khan Characterization of the putative vacuolar sugar transporter AtERDL4

10:15-10:30 Jessi Bak Characterizing the “regulin” family of SERCA-regulatory peptides

10:30-10:45 Antonietta Russo Translocon-associated protein (TRAP) complex and co-translational protein transport

10:45 – 11:00 Coffee break

Session 2 (Chair: Duc Phuong Vu)

11:00-11:15 Mark Sicking Malfunctions of kidney disease associated Sec61α mutations

11:15-11:30 Raelynn Brassard Understanding PARL-dependent cleavage of PINK1 in mitochondrial health and Parkinson's disease

11:30-11:50 Nilam Yadao Differential sorting of mitochondrial preproteins via the TIM23 machinery

11:50-12:10 Florian Wollweber Regulation of MICOS activity during mitochondrial cristae remodelling

12:10 – 13:00 Lunch

13:15 – 22:00 Visit of the Saarschleife & Saarburg (“Saarweinfest”)

Day Two (Tuesday, September 3, 2019)

08:00 – 09:00 Breakfast

Session 3 (Chair: Jonas Höring)

09:00-09:20 Gurleen Kaur Khandpur Changes in amino acid availability severely impacts yeast cell growth and redox homeostasis

09:20-09:40 Julian Oestreicher Identification of Opt3 as a putative endoplasmic reticulum-localized glutathione disulphide exporter

09:40-10:00 Eva Zöller Mix23 – a novel yeast protein in the intermembrane space of mitochondria

10:00-10:20 Janina Laborenz The ER-protein EMA19: a role in mitochondrial import?

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10:20 – 10:45 Coffee break

Session 4 (Chair: Leo Bellin)

10:45-11:00 Teqiyya Bentrcia A novel modulator of TRPC6 channel function

11:00-11:15 Megan Beggs Increased calcium permeability across small intestine in early life conferred by claudin-2

11:15-11:30 Xiong Liu Molecular mechanism of TRPP3 regulation by calmodulin

11:30 – 11:35 Short break Poster flash talks (Chair: Cristina Martins Rodrigues)

11:35-11:38 Leo Bellin Structural and functional insights into the ATCase of Arabidopsis thaliana

11:38-11:41 Wassilina Bugaeva Physiological analysis of the plastid fatty acid export proteins in Arabidopsis thaliana

11:41-11:44 Damayante Das The novel role of TMEM33 as a regulator of voltage gated Potassium channels

11:44-11:47 Daniel Fajonyomi Unique gating properties of Kv1.2 glycosylation deficient mutants

11:47-11:50 Jonas Höring Micellization thermodynamics of fluorinated and hydrogenated surfactants

11:50-11:53 Annalisa John Identification of chloroplast envelope proteins with critical importance for cold acclimation of Arabidopsis

11:53-11:56 Xiaobing Li Analysis of intracellular trafficking & localization of the human kidney anion exchanger 1 (kAE1) in yeast

11:56-11:59 Hasib Sarder Dissecting intracellular trafficking and mis-trafficking of human kidney AE1 in yeast and mammalian cells

11:59-12:02 Andrea Tirincsi Transmembrane protein 109 (TMEM109), a putative hsnd3 protein

12:02-12:05 Pratiwi Prananingrum The warm and high light stress; insight on a plastidic sugar transporter

12:05-12:08 Duc Phuong Vu Vacuolar sucrose mobilization is critical for the development of Arabidopsis thaliana

12:08-12:11 Janet Zhou The influence of selenium on arsenic hepatobiliary transport

12:30 – 13:30 Lunch

13:30 – 16:00 Hike / Time at free disposal (e.g. swimming, sports)

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16:00 – 18:00 Poster Session (including coffee break)

1 Leo Bellin Structural and functional insights into the ATCase of Arabidopsis thaliana

2 Wassilina Bugaeva Physiological analysis of the plastid fatty acid export proteins in Arabidopsis thaliana

3 Damayantee Das The novel role of TMEM33 as a regulator of voltage-gated potassium channels

4 Daniel Fajonyomi Unique gating properties of glycosylation-deficient Kv1.2 channels

5 Jonas Höring Micellization thermodynamics of fluorinated and hydrogenated surfactants

6 Annalisa John Identification of chloroplast envelope proteins with critical importance for cold acclimation of Arabidopsis

7 Hasib Sarder Dissecting intracellular trafficking and mis-trafficking of human kidney AE1 in yeast and mammalian cells

8 Xiaobing Li Analysis of intracellular trafficking & localization of the human kidney anion exchanger 1 (kAE1) in yeast

9 Andrea Tirincsi Transmembrane protein 109 (TMEM109), a putative hsnd3 protein

10 Pratiwi Prananingrum The warm and high light stress; insight on a plastidic sugar transporter

11 Duc Phuong Vu Vacuolar sucrose mobilization is critical for the development of Arabidopsis thaliana

12 Janet Zhou The influence of selenium on arsenic hepatobiliary transport

In order to allow guidance committee meetings at the posters and that the presenting trainees can visit the posters of their colleagues, the posters remain hanging the whole evening.

18:00 – 19:30 Guidance Committee Meetings Free choice of meeting places, e.g. hotel lobby, terrace, conference room, at the posters.

18:00–18:20

H. Sarder M. Schmitt E. Neuhaus E. Cordat

J. Laborenz J. Herrmann S. Lang N. Touret

F. Wollweber M. van der Laan M. Hoth J. Casey

T. Bentrcia V. Flockerzi T. Alexander

New trainees/ trainees without guidance committees L. Bellin (T. Möhlmann) J. Höring (S. Keller) A. John (E. Neuhaus) J. Oestreicher (B. Morgan) A. Tirincsi (S. Lang) M. Sicking (S. Lang)

18:20–18:40

A. Russo R. Zimmermann M. Hoth X-Z. Chen

G. Khandpur B. Morgan M. van der Laan N. Touret

W. Bugaeva E. Neuhaus K. Philippar J. Casey

K. Ravichandran J. Rettig V. Flockerzi ?

18:40 –19:00

C. Martins Rodrigues E. Neuhaus K. Philippar X.-Z. Chen

P. Schepsky J. Engel V. Flockerzi (H. Kurata)

N. Yadao M. van der Laan J. Herrmann J. Casey

M. Schöppe B. Niemeyer S. Lang T. Alexander

19:00-19:20

E. Zöller J. Herrmann M. van der Laan T. Alexander

D. Vu E. Neuhaus T. Möhlmann J. Lemieux

X. Li M. Schmitt B. Morgan E. Cordat

19:00 Barbecue at the “Eventhütte”

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Day Three (Wednesday, September 4, 2019)

08:00 – 09:00 Breakfast

Session 5 (Chair: Janina Laborenz)

09:00-09:20 Mona Schöppe Characterization of a novel splice variant of the stromal interaction molecule1 (STIM1)

09:20-09:40 Matthew Saurette Phosphorus source and intestinal absorption: inorganic phosphate is absorbed by the paracellular pathway

09:40-10:00 Cristina Martins Rodrigues To BEet or not to BEet. A short story about sugar beet transporters and their impact on cold acclimation

10:00-10:20 Katie Badior Investigation of RBC aging

10:20 – 10:45 Coffee break

Session 6 (Chair: Xiaobing Li)

10:45-11:05 Keerthana Ravichandran Characterization of flower containing vesicles in mouse cytotoxic T lymphocytes

11:05-11:25 Pauline Schepsky Slack (Slo2.2) K+ channels and the tight junction protein Claudin-12 in the cochlea

11:25-11:35 Barbara Niemeyer &

Joe Casey

Concluding remarks

11:35 – 12:00 Trainee & PI Meeting

12:00 - 13:00 Lunch / End of Meeting

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Abstracts in chronological order

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Characterization of the putative vacuolar sugar transporter, a homolog of

AtERDL6

Azkia Khan, Patrick Klemens & H. Ekkehard Neuhaus Department of Plant Physiology, University of Kaiserslautern, Germany

In plants, the central vacuole is the largest organelle and essential for plant growth. Within a

cell, the vacuole can serve as temporary storage for many metabolites and signaling

compounds. Both the availability of sugars and the accumulation of macro- and

micronutrients ensure proper plant growth. Sugars in plants provide energy for metabolic

processes as well as act as precursors in the synthesis of starch and amino acids. The

movement of sugar to and from the vacuole rely on numerous vacuolar transporters.

Vacuolar sugar transport is mediated by sucrose transporter family, the monosaccharide

transporters (MST) and members of a family called SWEET. Early response to dehydration

(ERD) 6–like1 (ESL1), is a member of the ERD-6-like clade, is a vacuolar protein and a

member of MST family. Other members of this clade are also targeted to the tonoplast. The

current study is on a homolog of AtERDL6, which we have identified as a vacuolar located

sugar carrier, induced by cold, drought and salt stress. GUS promoter analysis revealed its

expression mainly in the roots and pollens. Overexpressor and knockout plants also exhibit

variation in sugar accumulation under different stress conditions.

Characterizing the “regulin” family of SERCA-regulatory peptides

Jessi Bak & Howard Young Department of Biochemistry, University of Alberta, Edmonton, Canada

Calcium signalling is important for a multitude of physiological processes like skeletal and

cardiac muscle function, neurotransmitter release, and the cell cycle. Because of this central

role, it is tightly regulated at the intracellular level through the sarco(endo)plasmic calcium

ATPase, or SERCA. SERCA is a P-type ATPase that utilizes ATP to pump two calcium ions

across the membrane of the sarcoplasmic or endoplasmic reticulum membrane into the

lumen of the organelle for storage. This action is further regulated by single-pass

transmembrane peptides that interact with SERCA. Two regulators, phospholamban and

sarcolipin, have been investigated for a number of years but advances in bioinformatic

screening have led to the expansion of SERCA-regulatory peptides - a group that we now

refer to as the “regulins.” The regulins include myoregulin, another-regulin, endoregulin, and

DWORF, and these regulators are found in both muscle and non-muscle tissue. Our lab

studies the affect of these regulators on SERCA by co-reconstituting these components into

proteoliposomes and then measuring SERCA activity through a coupled-enzyme assay.

Here, our recent studies to understand these regulators will be presented.

Translocon-associated protein (TRAP) complex and co-translational protein

transport

Antonietta Russo Department of Medical Biochemistry and Molecular Biology, Saarland University, Homburg

A milestone in the understanding of protein translocation is the “Signal Hypothesis” proposed

by G. Blobel in 1971, which explains how the proteins are translocated from the cytosol into

the endoplasmic reticulum (ER). The signal peptide (SP) typically has the same structure but

it is very heterogeneous in protein sequence composition, this implies a fast evolution

probably connected with the mature protein.

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Nowadays, we know that the complexity of the SP meant to control many biological

processes: signal recognition particle (SRP) binding, interaction with the translocon Sec61

(gating), early folding prevention, signal peptidase (SPase) interaction and cleavage, and

even post-cleavage functions such as antigen presentation.

In the last years, much progress has been made to address the structure of the translocation

machinery, thanks also to the improved microscopic techniques such as Cryo-EM and Cryo-

ET; most of the structures are known, but the role of some components is still unclear.

TRAP is a heterotetrameric complex, α-β-γ-δ subunits, is located close to Sec61 complex,

where also TRAM, OST, SPase, Calnexin are present. It is a Ribosome Associated Protein

(RAP) that is involved in co-translation translocation; however, its role needs to be

determined. I will present computational and experimental results that can contribute to

shedding more light on the function(s) of TRAP at the molecular level and the entire

biological process.

Malfunctions of kidney disease associated Sec61α mutations

Mark Sicking1, Martina Zivna

2, Adolfo Cavalié

3, Richard Zimmermann

1 & Sven Lang

1

1Medical Biochemistry and Molecular Biology, Saarland University, Homburg;

2 Institute of Inherited Metabolic Disorders,

Charles University, Prague; 3 Experimental and Clinical Pharmacology and Toxicology, Saarland University, Homburg

The endoplasmic reticulum (ER) is a crucial organelle concerning the calcium homeostasis

and transport of nascent polypeptides in human cells. The heterotrimeric Sec61 complex is

an essential protein in the ER membrane and ensures a flawless functionality of the

mentioned processes. This complex forms an aqueous pore in the membrane, and the

entrance for multiple nascent proteins during their transport into or across the ER membrane.

During or shortly after the polypeptide transport, calcium leaks out through the complex from

the ER lumen into the cytosol in a regulated manner. Mutations in the main component of the

complex, the Sec61α protein, show multiple disease phenotypes in humans.

The two here investigated mutations of Sec61α, SEC61A1-V67G and SEC61A1-T185A, are

located at central positions of the protein and both variants cause forms of the Autosomal-

dominant tubulointerstitial kidney disease (ADTKD). However, the underlying pathogenic

mechanisms causing the Sec61α-related forms of ADTKD are unknown. In our cell culture

approaches we are using transgenic kidney cells, HEK293 cells, which express an

endogenous wild type and a mutated form of the Seec61α protein. This heterozygosity

mimics the patient families situation. Both mutations show a reduced protein transport

efficiency of specific substrates, both kidney related and unrelated polypeptides. The

reduced transport of affected substrates was traced back to the composition of their N-

terminal signal sequences. Furthermore, both mutations show multi-level irregularities of

calcium homeostasis. This includes, (i) the altered abundance of key players of calcium

homeostasis like SERCA2 or SOCE associated proteins, (ii) the suppressed sensitivity of the

mutants to the calcium leak modulating drug Eeyarestatin1, (iii) the slower Sec61-mediated

calcium leakage in case of the T185A variant, and (iv) the reduced calcium storage capacity

of the ER. Yet the small differences between the two Sec61α mutations, regarding protein

transport and calcium homeostasis could explain the phenotypic differences of the patients

and open up an interesting avenue of investigation. With the SEC61A1 gene being

expressed in all nucleated cells, there is still no explanation for the organ specificity of

SEC61A1 mutations associated diseases. Hence, we are currently studying other ER related

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processes like its ATP supply to address the issue of cell type specific defects and the

aforementioned phenotypic originalities.

Understanding PARL-dependent cleavage of PINK1 in mitochondrial health and

Parkinson's disease

Raelynn Brassard1, Elena Arutyunova

1, Laine Lysyk

1, Emmanuelle Tayki

2, Hélène Lemieux, Nicolas Touret

1 & Joanne

Lemieux1

Department of Biochemistry1 and Neuroscience and Mental Health Institiute

2, University of Alberta, Edmonton, AB, T6G 2R3.

Parkinson’s disease (PD) is a devastating neurodegenerative disease that is characterized

by a loss of dopaminergic neurons located in the substantia nigra. Mitochondrial dys-

regulation has been observed in numerous neurodegenerative diseases, including PD, due

to the high energy requirements of neuronal tissues.

Genetic mutations in the gene encoding for PINK1, have been associated with cases of early

onset PD. In a neuroprotective role, PINK1 accumulates on damaged mitochondria, flagging

them for destruction; while in healthy cells PINK1 is turned over by the PARL protease. PD

associated mutations are found near the PARL cleavage site and may lead to a loss of

PINK1 cleavage.

To reveal the etiology of PINK1 PD variants, in vivo analysis was conducted. Cleavage and

localization of the variants were assessed using confocal imaging and western blot analysis

of HeLa cells transfected with PD linked PINK1 variants. Like wild-type PINK1, all variants,

except the R98W mutant, displayed a diffuse pattern of PINK1 throughout the cell. The

PINK1-R98W PD variant displays high retention of the protein in the mitochondria.

These results were compared to in vitro cleavage analysis with recombinant PARL protease

and substrate, which shows no cleavage defect for the R98W variant, suggesting this variant

has defects in mitochondrial trafficking and not PARL processing. Thus, in these cells,

healthy mitochondria may be targeted for destruction with the PINK1-R98W mutation. To

evaluate this, assessment of mitochondrial respiratory function will be conducted. This work

provides insight into mutations causing early-onset inherited forms of PD.

Differenial sorting of mitochondrial prproteins via the TIM23 machinery

Nilam Yadao & Martin van der Laan Department of Medical Biochemistry and Molecular Biology, Saarland University, Homburg/Saar

The majority of mitochondrial proteins is encoded by nuclear genes and synthesized as

precursors in the cytosol. Mitochondrial preproteins contain a variety of import and sorting

signals that guide them to their destined locations within the organelles. The focus of my

project is the translocation and membrane-insertion of preproteins with amino-terminal

targeting signals. These proteins pass the outer membrane via the TOM complex and are

then taken over by the presequence translocase of the inner mitochondrial membrane, the

TIM23 complex. Depending on the physicochemical properties and sorting information of the

preproteins, they are either translocated completely into the matrix or integrated into the

inner membrane. Matrix import requires the interaction and close cooperation of TIM23 with

the presequence translocase-associated import motor. Membrane insertion of hydrophobic

preprotein segments via a stop-transfer mechanism is supported by the direct physical

coupling of proton-pumping respiratory chain complexes. It is unknown how transmembrane

segments are recognized by the TIM23 machinery and how they laterally escape from the

translocon into the lipid bilayer. Recent studies from my laboratory have shown that the small

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membrane-integral TIM23 subunit Mgr2 controls the lateral release of preproteins, likely via

interactions with charged amino acid residues flanking transmembrane segments. Site-

specific photo-crosslinking data suggest that Tim17 differentially interacts with hydrophilic

and hydrophobic preprotein segments within the protein-conducting pore of the TIM23

complex. In my studies, I use purified mitochondria from knock-out and conditional tim

mutants of the baker's yeast (Saccharomyces cerevisiae) to unravel how Tim17 and Mgr2

cooperate in the decoding of inner membrane sorting signals and the release of preprotein

segments into the phospholipid bilayer, a process referred to as "lateral gating". Supported

by IRTG1830

Regulation of MICOS activity during mitochondrial cristae remodelling

Florian Wollweber & Martin van der Laan

Department of Medical Biochemistry and Molecular Biology, Saarland University, Homburg/Saar

Mitochondria show a remarkable structural complexity as a result of their endosymbiotic

origin. Their double-membrane architecture is crucial for many essential functions in

metabolism and cell-fate decisions. The mitochondrial outer membrane connects

mitochondria to the cytosol and other organelles while the inner membrane harbours the

oxidative phosphorylation machinery for ATP synthesis and consists of a boundary region as

well as tubular or disc-shaped protrusions, termed cristae. One of the main organisers of this

intricate inner membrane ultrastructure is the mitochondrial contact site and cristae

organising system (MICOS), which is a large and highly conserved protein machinery that

can be found in all cristae-containing eukaryotes.

MICOS is essential for maintaining crista junction structure and creates a central hub for

mitochondrial biogenesis. Recent studies found that the two core subunits Mic10 and Mic60

form genetically and biochemically separable modules with distinct functions in membrane-

shaping and membrane-bridging to stabilise the membrane curvature at crista junctions and

connect mitochondrial protein machineries across multiple sub-organellar compartments. As

cristae are highly dynamic structures that have to adapt to e.g. altered metabolic demands of

the cell, the regulation of MICOS activity plays a pivotal role. We are currently investigating

how accessory MICOS subunits, such as the lipid-binding components Mic26/Mic27 and the

redox-regulated subunit Mic19 modulate the assembly of MICOS core subunits to coordinate

MICOS activities for cristae maintenance and remodelling.

Changes in amino acid availability severely impacts yeast cell growth and

redox homeostasis

Gurleen Kaur Khandpur1,4

, Martin Van der Laan2, Nicolas Touret

3 & Bruce Morgan

1

1Department of Biochemistry, University of Saarland, Germany

2Faculty of Medicine Medical Biochemistry and Molecular

Biology, University of Saarland, Germany, 3Department of Biochemistry, University of Alberta, Canada,

4Department of Biology,

Technical University of Kaiserslautern, Germany

Changes in amino acid handling have been observed in a wide-range of human pathologies

including diabetes and cancer. We used Saccharomyces cerevisiae as a model to

investigate how changes in amino acid availability influences cell growth and fitness.

Intriguingly, we observe that increasing the general availability of amino acids relative to the

availability of leucine leads to striking growth defects on glucose containing media. We also

observed that increasing the concentration of Ehrlich amino acids (amino acids which are

degraded to fusel acids/alcoholic compounds) in the media, severely impacts the growth of

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the cells which can be rescued by providing more Leucine. Furthermore, the deletion of Ilv2,

Ilv5 or Ilv3 (enzymes involved in leucine bio-synthetic pathway) makes the cell growth better

than wild type yeast cell in presence of increased amino acids availability. This growth

phenotype suggests that Ilv3 is the switching point and links the cellular growth and redox

homeostasis. Surprisingly, the amino acid-dependent growth phenotypes are completely

absent when cells grown in media containing non-fermentable carbon sources. We found

that deletion of the mitochondrial external NADH dehydrogenase-1 (Nde1) in combination

with Cox6 (an essential component of complex IV) partially rescued amino acid-dependent

growth phenotypes. However, deletion of the Nde1 homolog, Nde2, in combination with Cox6

had the opposite effect, further decreasing growth rate. We speculate that specific respiratory

chain components, but not the respiratory chain function per se, can play an important role in

‘buffering’ cells against these changes, although the mechanism remains to be determined.

Identification of a putative endoplasmic reticulum glutathione disulphide

exporter

Julian Oestreicher & Bruce Morgan Department of Biochemistry, Saarland University, Germany

In the endoplasmic reticulum the glutathione redox couple is generally believed to be more

oxidized than in the cytosol. However, it is unclear how glutathione redox homeostasis is

maintained with lacking glutathione reductase. In this study, we investigated the possibility

that the glutathione disulphide (GSSG) is exported from the secretory pathway in the cytosol

for reduction.

Specifically, we investigated the role of an uncharacterized, putative oligopeptide transporter

homolog, Opt3. We observed a synthetic lethality when OPT3 was deleted in combination

with either of the two glutathione biosynthetic enzymes, GSH1 or GSH2. We found that

manipulation of OPT3 expression levels affected whole cell GSSG concentrations, with

overexpression leading to a strong decrease in cellular GSSG content. These findings would

be consistent with a transport of GSSG to the cytosol where it is reduced. Upon targeting of

the glutathione synthetase, Gsh2, specifically to the ER, the impact of Opt3 expression level

on total cellular GSSG content was amplified. Finally, we demonstrate that the impact of

Opt3 on cellular GSSG levels is independent of the vacuolar-localized GGSG transporter,

Ycf1, therefore speaking against a role of Opt3 in regulating vacuolar GSSG storage. In

summary, we hypothesize that Opt3 mediates the export of GSSG from the endoplasmic

reticulum to the cytosol.

Mix23 – a novel yeast protein in the intermembrane space of mitochondria

Eva Zöller & Johannes Herrmann Department of Cell Biology, University of Kaiserslautern, Germany

Yeast cells synthesize the majority of their mitochondrial proteins in the cytosol which then

get imported into the mitochondria through their outer (OMM) and inner (IMM) mitochondrial

membranes. A variety of proteins targeted to the intermembrane space (IMS) relies on the

specific MIA pathway. Here, proteins enter the IMS in a reduced state and bind to Mia40, an

oxidoreductase that oxidizes the target proteins, which traps them in the IMS. In a proteome

screen, the cysteine containing protein Mix23 with unknown function was found to be

localized in the IMS. We could verify the IMS localization, the interaction with Mia40, and the

MIA dependent import of Mix23. In a RNA sequencing approach, we found Mix23 to be

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upregulated during import stress. Surprisingly, Mix23 is the only MIA substrate to be

upregulated under those circumstances. Furthermore, Mix23 is co-regulated with Mia40 and

the proteasome by the transcription factor Rpn4. This upregulation is specific to import stress

since it is not triggered by cytosolic aggregates. The import efficiency of MIA substrates was

not effected in a MIX23 deletion strain. Overexpression of Mix23 leads to a strong growth

phenotype. It is known that IMS proteins can be retro-translocated back into the cytosol for

their degradation. Due to the direct interaction of Mix23 with Mia40 and its cysteine rich

sequence, we hypothesize Mix23 to be one player in the so far uncharacterized retro-

translocation pathway. A number of experiments is planned to further investigate into this

direction.

The ER-protein EMA19: a role in mitochondrial import?

Janina Laborenz & Johannes Herrmann Department of Cell Biology, University of Kaiserslautern, Germany

Most mitochondrial proteins are initially synthesized in the cytosol as precursor proteins and

imported into mitochondria. While the import of soluble mitochondrial proteins was well

studied in the past, only little is known how cells manage to translocate the many

hydrophobic membrane proteins of the inner membrane. We developed a genetic screen in

yeast cells to identify genes that are critical for the efficient translocation of the hydrophobic

inner membrane protein Oxa1 into mitochondria. Surprisingly, in this screen we identified

several so far uncharacterized, though conserved ER proteins that are crucial for

mitochondrial targeting of Oxa1. By combining biochemical and genetic analysis we

characterized the function of the protein Djp1 in this process, which belongs to the family of

J-domain cochaperones of the Hsp70 system. We found that a large fraction of the newly

synthesized Oxa1 precursor associates with the ER surface from where it is recognized by

Djp1 to be directed to the mitochondrial outer membrane translocase. We propose that the

ER surface can serve as a collection system that facilities intracellular protein transport to

mitochondria. We called this import route the ER-SURF pathway. In addition to Djp1, we

identified an uncharacterized ER membrane protein, Ema19. First results about the function

of this protein in the context of mitochondrial preprotein sorting will be presented.

A novel modulator of TRPC6 function

Teqiyya Bentrcia & Veit Flockerzi Department of Pharmacology & Toxicology, Saarland University, Homburg, Germany

The canonical transient receptor potential channel 6 (TRPC6), a Ca2+ permeable cation

channel comprises four TRPC6 α subunits and may contribute to platelets function and

haemostasis. To identify the TRPC6 protein and potential β subunits of the channel in human

platelets, we generated antibodies for TRPC6, which enable protein detection in tissue

homogenates by Western blots. First, we established an antibody-based affinity purification

procedure to enrich solubilized TRPC6 protein from platelets. The bound TRPC6 protein was

eluted under non denaturing condition, run on blue native gels and analysed by mass

spectrometry. By the latter approach, the G-protein-coupled receptor kinase interacting

protein-1 (GIT1) and proteins of the phospholipase Cγ, ARHGEFs, ERK1, PAK2 and IP3R

pathway were found to be associated with the TRPC6 protein. In contrast, none of these

proteins were retained by a non-specific antibody used as a control. The physical interaction

between TRPC6 and GIT1 was confirmed by coimmunoprecipitation and in vitro pull down

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assays. We could show that the GIT1 protein binds to the TRPC6 protein via its ankyrin

repeat domain. Similarly, coimmunoprecipitation showed that the N-terminus of TRPC6 is

essential for TRPC6-GIT1 interaction. By calcium imaging as well as by patch clamp

recordings, calcium entry and TRPC6 currents are activated by diacylglycerol or its derivative

OAG. The OAG-induced calcium entry and current in HEK293 cells stably expressing Trpc6

cDNA was reduced in the presence of the GIT1 protein indicating a potential inhibitory effect

of GIT1 on TRPC6 mediated calcium entry and current. Calcium entry is required for cell

migration. In an in vitro migration scratch assay, we could show that the presence of GIT1,

results in slower migration. Furthermore, depletion of endogenous GIT1 protein by

overexpression of the TRPC6 N-terminus abolishes the inhibitory effect of GIT1 on TRPC6

function and results in larger currents and faster cell migration. This study identifies a novel

TRPC6 channel regulatory subunit (GIT1) which has a modulatory impact on TRPC6 channel

function. To elucidate the roles of TRPC6 and GIT1 in the phospholipase Cγ, ARHGEFs,

ERK1, PAK2 and IP3R containing signalom is the aim of our ongoing study.

Increased calcium permeability across small intestine in early life conferred by

claudin-2

Megan Beggs1, Allen Plain

1, Justin J. Lee

1 & R. Todd Alexander

1,2

1Physiology,

2Pediatrics, University of Alberta, Canada

Infants and children must maintain a net positive calcium (Ca2+) balance in order to achieve

an optimal peak bone mineral density by early adulthood. Across the small intestine, Ca2+ is

absorbed via transcellular and paracellular pathways although the molecular details of these

pathways in early life are not well delineated. Claudins are tight junction proteins that confer

selective permeability to epithelia. Claudins-2, -12 and -15 are expressed and have been

implicated in paracellular Ca2+ permeability across intestinal epithelia. To date, the functional

contribution of these claudins to the Ca2+ permeability (PCa2+) of small intestine segments has

not been defined. The objective of this study was therefore to 1) determine if PCa2+ across

small intestine segments changed with postnatal development 2) to asses whether claudin-2

or -12 contribute PCa2+

to the small intestine. To this end, basolateral to apical 45Ca2+ fluxes

on ex vivo intestinal segments in Ussing chambers were employed to indirectly assess

permeability to Ca2+. We observed greater 45Ca2+ flux in P14 vs 2-month mice across the

duodenum (31.8 ± 2.2 vs 9.5 ± 2.0 nmol/h/cm2, P<0.0001) and jejunum (42.3 ± 3.9 vs 21.8 ±

3.5 nmol/h/cm2, P<0.01) but not ileum (40.5 ± 3.2 vs 30.1 ± 5.7 nmol/h/cm2, P=0.13). Next,

we measured PCa2+ directly in Ussing chambers using diffusion potentials. PCa

2+ was

significantly greater in younger mice across the duodenum (1.43 ± 0.04 vs 1.13 ± 0.08 x10-

4cm/s, P<0.01), jejunum (1.64 ± 0.09 vs 0.84 ± 0.04 x10-4cm/s, P<0.0001) and ileum (1.72 ±

0.08 vs 0.81 ± 0.05 x10-4cm/s, P<0.0001). To determine if claudin-2 or -12 facilitates greater

PCa2+ at P14, diffusion potential experiments were repeated on Cldn2 or Cldn12 knockout

(KO) mice. PCa2+ was decreased in Cldn2 KO mice at P14 across the jejunum (1.85 ± 0.09 vs

1.24 ± 0.07 x10-4cm/s, P<0.0001) and ileum (1.92 ± 0.07 vs 1.09 ± 0.06 x10-4cm/s,

P<0.0001) to levels not different than 2-month WT and KO mice. No differences were

observed between Cldn12 knockout mice compared to wildtype littermates at either age. We

conclude that the younger mice have enhanced Ca2+ permeability along the small intestine

relative to older animals. Further, the increased jejunal and ileal Ca2+ permeability is

mediated by claudin-2 which likely contributes to a positive calcium balance for normal

growth.

15

Characterizing the role of CAM in TRPP3 channel function

Xiong Liu & Xing-Zhen Chen Department of Physiology, Membrane Protein Diseases Research Group, University of Alberta, Edmonton, AB, Canada, T6G 2H7

Transient receptor potential (TRP) polycystin-3 (TRPP3) is a non-selective cation channel

activated by calcium ions and protons and is involved in regulating ciliary calcium

concentration, hedgehog signaling and sour tasting. Previous reports have shown that

TRPP3 activation is followed by desensitization but the molecular basis underlying the

channel activation and the ensuing desensitization is not well understood. Calmidazolium

(CMZ), which is a commonly used calmodulin (CaM) antagonist, has been reported to

activate TRPP3 channel. Since CaM has been involved in the Ca2+ dependent regulation of

many TRP proteins, whether and how CaM regulates TRPP3 channel function has never

been explored. One possible mechanism is that CaM directly binding to TRPP3 channel

induces inhibitory effect and therefore the CaM antagonist, CMZ, will consequently activate

the channel. Another explanation is that CaM activating kinase, Ca2+/CaM dependent protein

kinase II (CaMKII) is inhibited by CMZ, leading to a functional TRPP3 form. In this study, we

observed that CaMKII and CaM decrease TRPP3 channel function. TRPP3 was

phosphorylated by CAMKII with ongoing experiments trying to identify the phosphorylation

site(s). We are also testing possible direct binding of CaM to TRPP3 and the role of Ca2+ in

the binding. These studies would allow to uncover how CaM blocks TRPP3 function. We

propose to verify that CaM promotes the inhibition of TRPP3 channel function through direct

interaction and CaMKII’s phosphorylation on TRPP3.

Support: Department of Physiology stipend, 75th Anniversary Graduate Student Award (to

XL), NSERC Discovery Grant, and Kidney Foundation of Canada Biomedical Grant (to XZC).

(Poster flash talk 1)

Structural and functional insights into the ATCase of Arabidopsis thaliana

Leo Bellin & Torsten Möhlmann

Department of Plant Physiology, University of Kaiserslautern

Pyrimidine nucleotides are some of the most crucial cellular metabolites for plant

development and growth. In plants, aspartate transcarbamoylase (ATCase), the enzyme

catalyzing the condensation of aspartate (Asp) and carbamoyl phosphate (CP) to carbamoyl

aspartate (CASP), is the control point of the de novo biosynthesis of pyrimidines.

This essential metabolic enzyme is unique in plants for being directly inhibited by uridine

mono-phosphate (UMP), the final product of the biosynthetic pathway. Despite numerous

biochemical and structural studies on ATCases from bacteria, fungi and animals, little is

known about ATCases in plants and no structural information has been reported so far.

In the course of this project we determined 6 different high resolution crystal structures of the

ATCase from Arabidopsis thaliana, providing first atomic detail about the catalytic and

regulatory mechanisms of this essential enzyme in plants. The structural data combined with

mutagenic, ITC and in vivo assays reveal the mechanism of inhibition by UMP.

In addition, we found out that the plant ATCase is a trimeric protein where only one subunit

can catalyze the reaction at a time. These results confirm that despite sharing an overall

structural similarity with the enzyme from other kingdoms, the ATCase in plants functions in a

different manner that could be targeted for the design of new herbicide strategies. Based on

the acquired structural and functional knowledge about Arabidopsis ATCase we propose

16

different approaches that could guide us in the development of plant specific ATCase

inhibitors.

Further and in addition to first insights into the structure- experiments for the relevance of the

ATCase in living plants have been performed. Thereby a reduction of the transcript by

artifical micro RNA leads to a drastical loss of biomass and to deficits in the development.

(Poster flash talk 2)

Physiological analysis of the plastid fatty acid export proteins in Arabidopsis

thaliana

Wassilina Bugaeva, Anne Könnel, Janick Peter & Katrin Philippar

Molecular Plant Biology, Center for Human- and Molecular Biology, Saarland University Saarbrücken, Germany

In plants, fatty acids (FAs) are synthesized in the plastid stroma and become available for

lipid assembly mainly in the form of long-chain FAs (C16–18). Some of these FAs are

integrated into lipids inside plastids (prokaryotic pathway), but the majority is exported to the

ER for further elongation, acyl editing, and lipid assembly (eukaryotic pathway). The

identification of FAX, a novel fatty acid export protein in the inner envelope membrane of

chloroplasts significantly contributes to the understanding of the FA transport mechanism

and the importance of FAX1 in plant development, biomass formation and fertility. In

Arabidopsis thaliana, seven proteins belong to the FAX family and besides FAX1, FAX2 and

FAX3 are also integrated into the inner envelope of chloroplasts. FAX2 and FAX3 are

assumed to partly complement FAX1 function due to increased transcript levels in leaves of

fax1 knockouts. Segregation analysis of fax1 single mutants and fax1/fax3 double mutants

on agar plates with and without sucrose shows a reduced amount of homozygous fax1/3

double mutants due to a missing complementation of FAX1 by FAX3. On soil, homozygous

fax1/3 double mutants are not viable, consequently the loss of both genes leads to a lethal

effect without additional carbon source supply.

Reference: Li et al. (2015) PLoS Biology. 13(2): e1002053

(Poster flash talk 3)

The novel role of TMEM33 as a regulator of voltage-gated potassium channels

Damayantee Das & Harley Kurata Department of Pharmacology, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Canada

The voltage gated potassium (Kv) channel Kv1.2 is a prominent potassium channel in the

CNS, playing an important role in regulating neuronal excitability and plasticity. Kv1.2

knockout mice have elevated seizure susceptibility, leading to 100% mortality by the third

post-natal week. Several channelopathies, including cerebellar ataxia, epileptic

encephalopathy, and hereditary spastic paraplegia are linked to Kv1.2 mutations. Kv1.2

channel structural and functional properties have been well studied, but its interactions with

regulatory proteins are still incompletely understood. Therefore, we aim to identify Kv1.2

channel regulatory proteins, in order to understand mechanisms that may impact channel

gating or proteostasis. Using mass spectrometry analysis of immunoprecipitated Kv1.2

complexes, we identified and validated several unknown regulatory proteins. One interacting

partner that stood out was TMEM33, an ER-resident molecule with effects on Kv1.2 channel

expression. Although TMEM33 is a conserved protein, little is known about its function, and it

is had not been previously recognized as a regulator of voltage-gated ion channels. This

17

study investigates mechanisms underlying TMEM33 regulation of Kv1.2, and how this may

lead to altered neuronal excitability.

EGFP-tagged TMEM33 prevents Kv1.2 trafficking to the cell surface and hinders maturation

into a fully glycosylated form. A strong suppression of Kv1.2 currents by EGFP-TMEM33 is

also observed. EGFP-TMEM33 generates a strong signal with Kv1.2 luminescence donors in

a BRET assay, suggesting their close proximity. TMEM33 is therefore a strong regulator of

Kv1.2 expression and function. Unlike Kv1.2, EGFP-TMEM33 did not affect Kv1.5 current

level and maturation. Current density measurements of different Kv1.2-Kv1.5 chimeras

suggested that substitution of the Kv1.2 pore abolished the effects of EGFP-TMEM33.

Untagged TMEM33, however, promotes total expression of Kv1.2 and rescues channel

surface expression in a TMEM33-knockout cell line. The distinct effects of N-terminally

tagged vs. untagged TMEM33 suggest that N-terminus of TMEM33 might have an important

functional role. Using a chimeric approach combining segments of Kv1.2 (TMEM33-

sensitive) and Kv1.5 (TMEM33-insensitive), we identify the pore and C-terminus of Kv1.2 as

critical determinants of TMEM33 sensitivity.

Channelopathies linked to Kv1.2 are associated with several diseases related to cell

excitability and epilepsy. Developing new knowledge into the regulatory mechanisms of

channel expression will contribute to a better understanding of these severe diseases. This

research will map out detailed biological functions of TMEM33, a poorly understood ion

channel regulator.

(Poster flash talk 4)

Unique gating properties of glycosylation-deficient Kv1.2 channels

Daniel Fajonyomi & Harley Kurata Department of Pharmacology, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Canada

Rationale: Kv1.2 channels are neuronal voltage-gated potassium ion channels belonging to

the Shaker (Kv1) family. Kv1.2 channels exhibit a unique behaviour termed use-dependent

activation (UDA), in which repetitive depolarizing stimuli produce progressive and

considerable increases in channel activity. However, the underlying molecular mechanism of

this behaviour is unknown. Previous work has demonstrated that mutation of a threonine at

position 252 of Kv1.2 to an arginine (Kv1.2 [T252R]) considerably diminishes use

dependence. Several lines of evidence have suggested that use-dependent activation of

Kv1.2 channels is due to an extrinsic regulatory molecule. To investigate the role of

glycosylation in the interaction of Kv1.2 with a candidate regulatory protein, the Kv1.2 N-

linked glycosylation site at residue N207 was mutated to an alanine (Kv1.2 [N207A]) or

glutamine (Kv1.2 [N207Q]), and effects on gating and maturation were tested.

Results: Kv1.2 [N207A] and Kv1.2 [N207Q] mutant channels exhibit dramatically slower

activation kinetics, slower deactivation kinetics, and a positive shift in voltage-dependence of

activation compared to WT Kv1.2. A signature feature of use-dependent activation is that

repetitive activation of Kv1.2 channels leads to accelerated activation. Similarly, the

activation kinetics of Kv1.2 [N207A] are markedly accelerated with prior stimuli. Furthermore,

the T252R mutation in Kv1.2 strongly attenuates sensitivity to use-dependent activation.

Engineering this mutation into glycosylation deficient [N207A] channels significantly reduces

the effects of the N207 mutation on the kinetics and voltage-dependence of channel

activation. Lastly, co-expression of glycosylation deficient channels with Slc7a5, a novel

regulator of Kv1.2, appears to occlude the use-dependent activation mechanism of Kv1.2.

This regulatory effect of Slc7a5 also affects the slow gating properties of Kv1.2[N207A]

18

channels, leading to significant acceleration of activation, along with a negative shift in

voltage-dependence of activation.

Conclusions: Slow activation kinetics and altered voltage-dependence of glycosylation

mutants are caused by increased sensitivity to use-dependent activation. These findings

suggest a previously unrecognized role for glycosylation as a regulator of Kv1.2 sensitivity to

extrinsic regulatory processes.

(Poster flash talk 5)

Temperature dependence of fluorinated-surfactant micellization

Jonas Höring1, Grégory Durand

2 & Sandro Keller

1

1Molecular Biophysics, University of Kaiserslautern, Kaiserslautern, Germany; 2Institut des Biomolécules Max Mousseron, University of Avignon, Avignon, France

Membrane proteins (MPs) are crucial for plentiful physiological processes of the cell. This

makes the comprehension of their structure paramount for, among others, the

pharmaceutical industry, as MPs represent more than 60 % of drug targets. However,

compared with soluble proteins, only a small number of high-resolution structures of MPs are

available. This is rooted in their embedment in the lipid bilayer, which hampers the

accessibility of MPs to biophysical investigation [1]. Therefore, it is essential to extract MPs

from their native membrane. While canonical detergents, due to their solubilizing nature, are

well-suited for the extraction of MPs, they are often invasive towards the structure of the MP.

Therefore, new approaches have emerged to combine detergent capability for membrane

extraction with a milder effect on MPs to form membrane-mimetic systems for the study of

MPs [2]. Fluorinated surfactants are one of the compounds which were designed for this

task. The bulky, fluorinated carbon tail of these molecules renders them both hydrophobic

and lipophobic, resulting in poor miscibility with hydrocarbon chains. Therefore, fluorinated

surfactants are less invasive towards extracted MPs compared with hydrocarbon-based

surfactants, rendering their micelles promising membrane-mimetic systems [3]. To gain

detailed insight into the molecular mechanisms underlying the mildness of fluorinated

surfactants toward MPs, we characterized their micellization behavior by several calorimetric

techniques. In particular, we studied the temperature-dependent properties of micellization of

a homologous series of fluorinated surfactants and their hydrogenated analogs. Isothermal

titration calorimetry (ITC) was utilized to investigate the temperature dependence of their

critical micellar concentration, as well as to allow a full thermodynamic characterization of the

micellization. Differential scanning calorimetry (DSC) was employed to further explore

micellization of the surfactants and the associated heat-capacity changes over a wide

temperature range. Data from both methods were compared to show differences between

corresponding critical micelle concentrations and critical micelle temperatures of the

surfactants.

References

[1] Y. Arinaminpathy et al., Drug Discovery Today 14, 23/24, 1130–1135 (2009)

[2] J.-L. Popot, Annual Review of Biochemistry 79, 737–775 (2010)

[3] G. Durand et al., in Membrane Proteins Production for Structural Analysis chapter 8, Ed.

I. Mus-Veteau, Springer, New York, USA, 205–251 (2014)

19

(Poster flash talk 6)

Identification of chloroplast envelope proteins with critical importance for cold

acclimation of Arabidopsis

Annalisa John , Oliver Trentmann & Ekkehard Neuhaus Department of Plant Physiology, University of Kaiserslautern, Kaiserslautern, Germany

Higher plants are organisms performing a sessile lifestyle and thereby are exposed to many

different weather and temperature conditions. Especially coldness shows a great effect on

plant vitality, mainly because of a downregulation of enzymatic reactions, a decreased fluidity

of membranes and the damage by ice crystals. This is why plants like Arabidopsis thaliana

developed different strategies to cope with low temperatures and become cold-hardy. A

common adaption while acclimation is the storage of different solutes like sugars in the

vacuole to function as osmotica and prevent dehydration. Next to the involvement of the

vacuole, cold acclimation is a more complex process including also other organelles like the

chloroplast. Not only photosynthesis takes place in here, the chloroplast functions as a

central coordinator of metabolic adjustment and acclimation processes. Proteome analysis of

chloroplast envelopes of cold treated Arabidopsis plants identified proteins with critical

importance for cold acclimation. Some of them are already known and analyzed, like the

plastidic ATP/ADP antiporter NTT2, the maltose translocator MEX1 or the fatty acid exporter

FAX1. But in this connection also new proteins were identified and thereby the most

interesting candidates like e. g. a small RAB-B-class GTPase, a putative steroid-5-alpha

reductase and a putative subfamily F ABC protein were selected because they showed the

highest alterations in relation to the protein content compared to the others. To gain a first

insight in the impact of these proteins for adaption to lower temperatures the phenotype of

corresponding Arabidopsis knock-out lines should be investigated, especially while cold

treatment. In future work the creation of overexpressing lines is planned as well as

subcellular localization studies.

(Poster flash talk 7)

Dissecting intracellular trafficking and mis-trafficking of human kidney AE1 in

yeast and mammalian cells

Hasib A. M. Sarder, Björn Becker & Manfred J. Schmitt Molecular & Cell Biology, Department of Biosciences, Center of Human and Molecular Biology (ZHMB), Saarland University, D-66123 Saarbrücken, Germany

Kidney anion exchanger 1 (kAE1) is a membrane protein located in the basolateral

membrane of α-intercalated cells (A-IC) of the human kidney which is responsible for the

reabsorption of bicarbonate ions (HCO3-) by exchanging with chloride ions (Cl-), thereby,

ensuring acid excretion in the urine [1]. Various genetically inherited mutations in the kAE1

encoding gene have been reported to negatively affect HCO3-/Cl- exchange and ultimately

result in clinical disorders known as distal renal tubular acidosis (dRTA). Until now,

autosomal dominant (AD) and recessive (AR) mutations have been identified [2], but the

underlying molecular mechanisms for the disease are still poorly understood. In this study,

we are using baker’s yeast (a simple eukaryotic model organism) and a mouse kidney cell

line (mIMCD3) to dissect the pathological reasons of dRTA. So far, a yeast codon-optimized

kAE1 variant could be successfully expressed as full-length protein in yeast. Proper kAE1

localization at the cell periphery was confirmed via indirect immunofluorescence microscopy,

cell surface biotinylation experiments as well as colocalization with the yeast plasma

membrane marker Pma1p. In vivo functionality of kAE1 was analyzed by using a pH-

20

sensitive ratiometric dye. Furthermore, during my research stay at the Cordat Lab in Canada,

I was focused on the characterization of novel dominant and recessive dRTA mutants

(R296H, Y413H and S525F) by using mIMCD3 cell line, the closest cellular model for A-IC at

the moment. All the mutants showed less stability in degradation assays as well as the p62

levels, a reporter protein for active autophagy, was likewise upregulated compared to the

wild-type situation. However, a cytotoxic effect after expression of these kAE1 mutants was

not observed under hyperosmotic condition.

(Poster flash talk 8)

Analysis of intracellular trafficking and localization of human kidney anion

exchanger 1 (kAE1) in yeast

Xiaobing Li, Björn Becker & Manfred J. Schmitt Molecular and Cell Biology, Department of Biosciences and Center of Human and Molecular Biology (ZHMB), Saarland University, D-66123 Saarbrücken, Germany

Human kidney anion exchanger 1 (kAE1) represents a bicarbonate transporter in the

basolateral membrane of renal epithelial cells that participates in the fine-tuning of acid-base

homeostasis by mediating electroneutral Cl-/HCO3- exchange. Several autosomal mutations

in the kAE1 encoding gene (SLC4A1) can cause clinical disorders known as distal renal

tubular acidosis (dRTA) which are linked to kAE1 misfolding, ER/Golgi retention, and/or

premature degradation. Despite that some proteins involved in kAE1 trafficking had been

identified, the precise mechanism(s) resulting in dRTA still remain unclear. In this study, we

are using yeast as experimental model system to identify proteins which affect intracellular

kAE1 trafficking to the plasma membrane and/or its turnover, both of which is vital for proper

kidney function. Our current data indicate that kAE1 can be successfully expressed in yeast

and partially colocalizes at the plasma membrane. However, kAE1 overexpression leads in

part to the intracellular kAE1 aggregation which subsequently induces a strong UPR

activation in yeast cells. In further experiments, we aimed to address the underlying

principles resulting in kAE1 aggregation and to identify tools to finally prevent or at least

minimize intracellular kAE1 protein accumulation in yeast. Furthermore, we will initially

establish a fluorescence-based screening approach in S. cerevisiae to test to which extent

the overexpression of single yeast genes can modulate both cellular expression and plasma

membrane localization of kAE1.

This study is kindly supported by the Deutsche Forschungsgemeinschaft (IRTG 1830).

(Poster flash talk 9)

Transmembrane protein 109 (TMEM109), a putative hsnd3 protein

Andrea Tirincsi, Sarah Haßdenteufel, Monika Lerner, Mark Sicking, Sven Lang & Richard Zimmermann Medical Biochemistry & Molecular Biology, Saarland University, Homburg

Protein transport to the endoplasmatic reticulum (ER) mostly relies on the signal recognition

particle (SRP) pathway. However, tail-anchored proteins can be transported into the ER in an

SRP independent (SND) manner. Previous work identified the SND pathway in S. cerevisiae

and we aim to identify it in human cells. The SND pathway has three components (hsnd1, 2,

3) so far no human hsnd3 protein has been identified. Here we report transmembrane protein

109 (TMEM109) as a putative hsnd3 protein, which might be involved in the SND targeting

machinery. TMEM109 also known as Mitsugumin23 (MG23) is a transmembrane protein

21

within the ER and in the nuclear membrane and has been described as a calcium channel

within the ER membrane.

Co-immunoprecipitation experiments showed an interaction between hsnd2 and TMEM109.

Further mass spectrometry analysis revealed the simultaneous reduction of TMEM109 with

hsnd2 depletion; this might suggest that they are associated within the snd pathway. Here

we report our initial results about TMEM109 as a putative hsnd3 protein and its role in

calcium homeostasis.

(Poster flash talk 10)

The warm and high light stress; insight on a plastidic sugar transporter

Pratiwi Prananingrum, Kathrin Patzke, Patrick A.W. Klemens, Oliver Trentmann, Ilka Haferkamp & H. Ekkehard Neuhaus Department of Plant Physiology, Faculty of Biology, University of Kaiserslautern, Germany

The major carbohydrates in plants are glucose, fructose, sucrose, cellulose and starch. The

transport of sugars across membrane barriers is essential for higher plants, since sugar

represents transport and storage units of cellular energy generation and thus play a

fundamental role during developmental processes and stress responses. In addition to

transport across the plasma membrane, carrier-mediated sugar transport has also been

demonstrated across organellar membranes, such as the inner plastid envelope or the

vacuolar membrane, named tonoplast. The monosaccharide transporter family is diverse. In

this study, we will focus on VGT-like protein family of monosaccharide transporter in which

comprised of three genes Arabidopsis thaliana Vacuolar Glucose Transporter 1 (AtVGT1),

AtVGT2, and AtVGT3. Recently, two genes from this family, AtVGT1 and AtVGT2 have been

shown to localize to the vacuolar membrane of Arabidopsis thaliana (A. thaliana) (Aluri and

Büttner, 2006). It has been shown that VGT1 transports glucose and a proton-coupled

antiport. In contrast, here we characterize that the protein encoded by AtVGT3 (we further

address it as plastidic sugar transporter /pSuT), locates to the chloroplast membrane.

Transport analyses with yeast cells expressing a truncated, vacuole-targeted version of pSuT

indicate that both glucose and Suc act as substrates, and nonaqueous fractionation supports

a role for pSuT in Suc export from the chloroplast. The latter process is required for a correct

transition from vegetative to reproductive growth and influences inflorescence architecture.

Moreover, pSuT play a role in the adaptation to the warm, cold, and high light stress. These

data further underline the central function of the chloroplast for plant development and the

modulation of stress tolerance.

(Poster flash talk 11)

Vacuolar sucrose mobilization is critical for the development of Arabidopsis

thaliana

Duc Phuong Vu & Ekkehard Neuhaus Department of Plant Physiology, University of Kaiserslautern, Germany

Sugars are involved as signal molecules in plant development. To achieve these functions,

cellular sugar homeostasis must be tightly regulated, via control of membrane transporters

and enzyme activities. Among these enzymes are the vacuolar invertases, which cleave

sucrose into glucose and fructose.

To study the impact of an altered sugar homeostasis on Arabidopsis thaliana development

by increasing the luminal sucrose concentration, we generated amiRNA lines targeting both

22

vacuolar invertases. The mutants showed increased sucrose concentrations and decreased

monosaccharides levels. The early plant development is delayed, most probably because of

a blocked sugar mobilization. In addition, plant seed yield is decreased and impaired sugar

export from source to sink tissues might contribute to this.

Hence, vacuolar sucrose mobilization is of superior importance for modulation of plant

development and seed weight.

(Poster flash talk 12)

Studying the influence of selenium on arsenic hepatobiliary transport

Janet R. Zhou1,2

, Gurnit Kaur1,2

, Denis Arutyunov2,3

& Elaine M. Leslie1,2,3

1. Division of Analytical and Environmental Toxicology, Department of Laboratory Medicine and Pathology, University of Alberta, Canada; 2. Membrane Protein Disease Research Group, University of Alberta, Canada; 3. Department of Physiology, University of Alberta, Canada

Background: Worldwide, at least 200 million people are exposed to the proven human

carcinogen arsenic at levels exceeding the World Health Organization guideline (10 µg/L). In

animal models arsenic and selenium are mutually protective via the formation and biliary

excretion of the seleno-bis (S-glutathionyl) arsinium ion [SeAs(GS)2]-. Despite ongoing

human selenium supplementation trials in arsenic endemic regions, the influence of selenium

on human hepatic handling of arsenic is not adequately understood. We hypothesized that

selenium would increase the biliary excretion of arsenite (AsIII) from human HepaRG cells, an

immortalized cell lined used as a surrogate for primary human hepatocytes.

Objective: To study the influence of selenite (SeIV), selenide (SeII), methylselenocysteine

(MSC) and selenomethionine (SM) on arsenic efflux from HepaRG cells.

Methods: Fluorescence microscopy after treatment with 5(6)-carboxy,2’,7’-

dichlorofluorescein (CDF) diacetate was performed to visualize the canalicular networks and

assess function of multidrug resistance protein 2 (MRP2/ABCC2), which transports

conjugated and unconjugated organic anions, including [SeAs(GS)2]- into bile. The

expression of genes involved in hepatic arsenic metabolism (As3MT) and efflux transport

(ABCC2 and ABCC4) were assessed with an agarose gel. Crude membrane preparations

subjected to SDS-PAGE and immunoblots were used to determine if MRP2 and the related

arsenic sinusoidal transporter multidrug resistance protein 4 (MRP4) were present at the

protein level. HepaRG cells were treated with 73AsIII ± SeIV, SeII, MSC or SM (1 µM) and

efflux was measured across sinusoidal and canalicular membranes. Biliary excretion indices

(BEIs) were calculated to quantify biliary excretion.

Results: CDF accumulated in canalicular networks, suggesting the presence of functional

MRP2. ABCC2, ABCC4, and As3MT are expressed in the cell line, and MRP2 and MRP4

proteins were detected by immunoblot. SeII increased biliary excretion of 73AsIII, with a BEI of

24%, but other forms of selenium did not.

Conclusion: This work will lead to a better understanding of the influence of selenium on

arsenic handling by human liver and provide valuable information for ongoing selenium-

supplementation trials.

23

Characterization of a novel splice variant of the stromal interaction molecule 1

(STIM 1)

Mona Schöppe1, Kathrin Förderer

1, Yvonne Schwarz

3, Annette Lis

2 & Barbara Niemeyer

1

1Molecular Biophysics, Saarland University, 66421 Homburg, Germany/

2Biophysics, Saarland University, 66421 Homburg,

Germany/ 3Molecular Neurophysiology , Saarland University, 66421 Homburg, Germany

Changes in intracellular free calcium concentration [Ca2+] probably represent the most

widespread and important signaling event in cellular physiology, since transient elevations of

Ca2+ directly or indirectly control and regulate a plethora of cellular responses. Therefore

cells must be able to react to minor changes in [Ca2+]i and changes must be tightly regulated.

The major Ca2+ pathway in electrically nonexcitable cells is the store operated calcium entry

(SOCE) via calcium release activated calcium channels. The Ca2+ selective channel is

located in the plasma membrane and formed by Orai-family proteins. Stromal interaction

molecule (STIM1 and STIM2) proteins activate SOCE by sensing changes in the luminal

Ca2+ concentration in the endoplasmic reticulum via their N-terminal EF hand motif. Upon

store depletion, STIM molecules change conformation, multimerize and trigger SOCE by

directly gating Orai channels within ER-PM junctional regions.

Here, we report the identification and characterization of a novel STIM1 splice variant,

STIM1A, which retains an additional 31 amino acid long exon within its C-terminal cytosolic

region. The so called exon A is spliced into the mRNA downstream of the channel activating

region and also downstream of a region encoding an acidic inhibitory domain (ID) that

mediates fast Ca2+ inactivation of Orai1. On mRNA level the variant is ubiquitously

expressed, but its abundance relative to the more common STIM1 variant varies upon cell

type. In contrast to the RNA analysis, STIM1A could be detected only in murine testis on

Western blots. Transient overexpression of the splice variant leads to an overall reduced

SOCE and ICRAC when compared to STIM1, whereas a knockdown leads to an increased

SOCE. The new splice variant colocalizes with the wildtype STIM1 upon co-overexpression.

Furthermore, the interaction with Orai1 is not impaired. Using mutation assays, two specific

amino acids within the exon A could be identified to be responsible for the Ca2+ phenotype

of the splice variant. Future experiments aim to understand the physiological role of STIM1A

in Testis and to identify splice-specific interaction partners.

Supported by IRTG 1830 and SFB 894

Phosphorus source and intestinal absorption: inorganic phosphate is ab-

sorbed by the paracellular pathway

Matthew Saurette1,2

, Tate MacDonald1,2

& R. Todd Alexander1,2,3

1. Department of Physiology, Membrane Protein Disease Research Group, University of Alberta, Edmonton, Alberta, T6G 2H7, Canada. 2. The Women’s and Children’s Health Research Institute, Edmonton, Alberta, T6G 1C9, Canada. 3. Department of Pediatrics, University of Alberta, Edmonton, Alberta, T6G 2R7.

Hyperphosphatemia, elevated serum phosphate (Pi), is an electrolyte imbalance frequently

occurring with chronic kidney disease (CKD) and end stage renal disease (ESRD).

Hyperphosphatemia is associated with a number of negative sequelae including decreased

renal function, cardiovascular disease and death. Consequently, lowering serum is a clinical

priority for patients with CKD and ESRD. One of the main ways to reduce serum Pi is

reducing the amount of Pi ingested. There are two main forms of Pi in our diet: organic and

inorganic. Protein is one of the main sources of organic Pi and, therefore, reducing dietary Pi

often requires reducing protein consumption which can lead to protein malnutrition. Inorganic

Pi is a common food additive and preservative, and are ubiquitous in the “Western” diet.

Compared to organic Pi, inorganic Pi is more bioavailable, however, it is unclear why. We

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hypothesized that inorganic Pi is more bioavailable than organic Pi because it does not

require digestion therefore is readily absorbed down the intestinal electrochemical gradient

(N.B. the intestinal lumen is – 5 mV relative to blood).

To test our hypothesis, wild-type and claudin-12 null mice were consecutively placed on an

organic then predominantly inorganic Pi diet in metabolic cages, permitting urine and feces

collection. The total amount of Pi in each diet was identical (0.7%). Claudin-12 is a tight

junction protein that we propose blocks paracellular Pi flux. Urinary and fecal Pi excretion,

and Pi bioavailability were determined for mice fed each diet to assess differences between

organic and inorganic Pi absorption. Both wild-type and claudin-12 null mice had increased

oral Pi bioavailability and urine Pi excretion on the inorganic Pi diet, consistent with

enhanced intestinal absorption. In contrast, potassium, another ion absorbed by the

paracellular route in the gut, did not display differences in oral bioavailability or urinary

excretion between the different diets. Further, claudin-12 null mice had significantly greater

oral Pi bioavailability, serum Pi and urine Pi excretion relative to wild-type mice on the

inorganic but not organic Pi diet. Our data confirms that inorganic Pi is more bioavailable

than organic Pi and is consistent with i) claudin-12 forming a paracellular Pi barrier that

inhibits inorganic but not organic Pi absorption and ii) organic Pi being absorbed through the

paracellular pathway. Ultimately this works provides biological rationale for CKD/ESRD

patients to consume diets low in inorganic phosphate and provides a molecular target to help

block intestinal Pi absorption.

To BEet or not to BEet. A short story about sugar beet transporters and their

impact on cold acclimation

Cristina Martins Rodrigues & Ekkehard Neuhaus Department of Plant Physiology, University of Kaiserslautern, Germany

Sugar beet (Beta vulgaris) is the exclusive sugar source for the food industry in temperate

climate zones (Europe and North America). Sugar beet taproots accumulate sucrose to as

much as 20% of their fresh weight at maturity. Although a biennial plant species, sugar beet

is grown annually due to its prominent sensitivity to freezing. A protective mechanism of

higher plants against low temperatures is the accumulation of soluble solutes, especially

sugars. The accurate compartmentalization of sugars into the vacuole, the cellular sugar

storage organelle, is guided by several sugar carriers. To understand how an altered

compartmentalization of the distinct sugar species might influence the cold response of

plants, we investigated the behavior of different Arabidopsis thaliana lines each

overexpressing one of the mentioned sugar carriers deriving from sugar beet. Therefore, we

analyzed the metabolic status and expression pattern during the onset of cold.

Investigation of RBC aging

Katie Badior Department of Physiology, University of Alberta, Edmonton, Canada

During their circulating lifetime of 120 days, RBCs are exposed to extreme physical and

chemical stresses. As damages accumulate, aged RBC transport function becomes less

efficient, and they must be removed from circulation. Aged RBCs are removed by white

blood cells of the immune system.

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White blood cells recognize aged RBCs through antibody mediators, which I turn recognize

the major membrane protein component on RBCs, Band 3. Previous studies indicate that

there are two regions of Band 3 (epitopes) in particular that are recognized by these

antibodies, comprising amino acid residues 538-553, and 813-830. Recently, the 813-830

region was shown to be inside the red cell, where it would be inaccessible to antibodies in

blood sera. We propose that the Band 3 epitope marking RBCs as ‘aged’ to antibodies is

dynamic, and can access both the intracellular and extracellular sides of RBC membranes.

The ability of these Band 3 senescence epitopes to access the extracellular environment was

assessed using substituted cysteine scanning mutagenesis and antibody binding assays,

using an HEK293 cell model.

In our model of RBC aging red cell viability is damaged over time following antibody binding

to Band 3. This has implications for developing strategies improving RBC storage and shelf

life, as well as increasing transfusion efficiency.

Characterization of flower containing vesicles in mouse cytotoxic T lympho-

cytes

Keerthana Ravichandran, Claudia Schirra & Jens Rettig. Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, Homburg/Saar, Germany

A transmembrane protein, flower, was shown to be associated in synaptic vesicle

endocytosis in neurons (Yao et al., 2009) and our group recently have shown that flower

consists of four transmembrane domains with its N- and C-terminus facing the cytoplasm.

We further demonstrated that it plays an important role in regulating cytotoxic granule (CG)

endocytosis in primary cytotoxic T lymphocytes (CTLs), which was delayed in cells from

flower KO mice. Despite these findings, it is still not clear how and from where flower exerts

the action of controlling endocytosis. Endocytosis as such in CTLs is important for function in

serial killing of target cells. The endogenous expression of flower by immunocytochemistry

was found to be very low but found mostly in vesicles and partially at the plasma membrane.

Real time killing assay with different effector: target cell ratios show a clear defect in multiple

killing efficacy of flower KO CTLs. To further understand the endogenous localization of the

protein, flower-Halo-HA knock-in mouse was generated using CRISPR-CAS9 gene editing

technology and the fusion protein was characterized using specific antibodies. The major aim

of this study is to find the localization of the protein flower and characterize the proteome of

flower containing vesicles and subsequently decipher a possible mechanism of how flower

aids the CGs in endocytic process.

Slack K+ channels and the tight junction protein Claudin-12 in the cochlea

Pauline Schepsky & Jutta Engel Biophysics, Saarland University, Homburg, Germany

Slack (Slo2.2, gene Kcnt1) is a Na+- and voltage-activated potassium channel that reduces

neuronal excitability in response to neuronal activation and Na+ influx. Slack mRNA and

Slack currents have been described in spiral ganglion neurons (SGN; Reijntjes et al.,

Scientific Reports 2019). The role of Slack in hearing however is unknown. I have

characterized hearing of 8 week-old Slack-/- mice by recording auditory brainstem responses

(ABR). Slack-/- mice had normal hearing thresholds. We hypothesized that Slack counter-acts

neuronal excitation and may reduce noise-induced cochlear damage. Therefore Slack-/- and

wild type mice were subjected to a mild noise trauma (100 dB SPL, 2 hrs, 8 – 16 kHz band

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noise). The shift in hearing thresholds was assessed directly after trauma and between one

and 28 days after trauma. Thereafter, cochleae were analyzed for numbers and localization

of presynaptic ribbons and postsynaptic protein clusters.

Tight junctions are essential for cellular compartmentalization transforming tissues to highly

complex functional systems. In the cochlea, various claudins that are important components

of tight junctions form the paracellular barrier between the endolymph and perilymph

compartments and thereby maintain the large concentration differences of K+, Na+ and Ca2+

as well as the endocochlear potential needed for normal cochlear function.

Preliminary results point to mRNA expression of claudin-12 (Cldn12) in the cochlea but the

cellular expression pattern had not been identified. During my stay in Dr. Alexander’s

laboratory in Edmonton I analyzed the cellular expression of claudin-12 in the cochlea of

adult mice. By using claudin-12 knockout mice carrying a LacZ-reporter construct I found

strong promoter activity of claudin-12 exclusively in inner hair cells.

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List of Participants

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Alexander, Todd Department of Pediatrics Division of Nephrology & Physiology 2B2.42 Walter Mackenzie Centre University of Alberta Edmonton, Alberta, Canada, T6G 2R7 todd2@ualberta.ca

Amoroso, Gabriele Department of Plant Physiology Faculty of Biology University of Kaiserslautern Erwin-Schrödinger-Straße 67663 Kaiserslautern Germany gamoroso@rhrk.uni-kl.de

Badior, Katie Department of Biochemistry Faculty of Medicine & Dentistry University of Alberta 4020E Katz Group Rexall Building Edmonton, Alberta, Canada, T6G 2E1 badior@ualberta.ca

Bak, Jessi Department of Biochemistry Faculty of Medicine & Dentistry University of Alberta 327 Medical Sciences Building Edmonton, Alberta, CanadaT6G 2H7 jessi@ualberta.ca

Beggs, Megan Department of Pediatrics Division of Nephrology & Physiology 2B2.42 Walter Mackenzie Centre University of Alberta Edmonton, Alberta, Canada, T6G 2R7 mbeggs@ualberta.ca

Bellin, Leo Department of Plant Physiology Faculty of Biology University of Kaiserslautern Erwin-Schrödinger-Straße 22 67663 Kaiserslautern Germany bellin@rhrk.uni-kl.de

Bentrcia, Teqiyya Department of Experimental & Clinical Pharmacology & Toxicology Faculty of Medicine Saarland University University Hospital Building 46 66421 Homburg Germany teqiyya.bentrcia@uks.eu

Brassard, Raelynn Department of Biochemistry School of Translational Medicine Faculty of Medicine & Dentistry University of Alberta 451 Medical Sciences Building Edmonton, Alberta, Canada T6G 2H7 rbrassar@ualberta.ca

Bugaeva, Wassilina Department of Plant Biology Faculty of Natural Sciences & Technology Saarland University University Hospital, Building A 2.4 66421 Homburg /Saar Germany lina.bugaeva@uni-saarland.de

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Casey, Joe Department of Biochemistry Faculty of Medicine & Dentistry University of Alberta 4020 E Katz Group Rexall Building Edmonton, Alberta, Canada, T6G 2E1 casey@ualberta.ca

Chen, Xing-Zhen Department of Physiology Faculty of Medicine & Dentistry University of Alberta 7-29A Medical Sciences Building Edmonton, Alberta, Canada, T6G 2H7 xzchen@ualberta.ca

Cordat, Emmanuelle Department of Physiology School of Moleclar & Systems Medicine University of Alberta Medical Sciences Building/Room 7-34 Edmonton, Alberta, Canada, T6G 2H7 Cordat@ualberta.ca

Das, Damayantee Department of Pharmacology Faculty of Medicine & Dentistry University of Alberta 6-040 Li Ka Shing Centre Edmonton, Alberta, Canada ddas1@ualberta.ca

Deitmer, Joachim Department of General Zoology Faculty of Biology University of Kaiserslautern Erwin-Schrödinger-Straße 13 67663 Kaiserslautern Germany deitmer@biologie.uni-kl.de

Engel, Jutta Department of Biophysics Faculty of Medicine Saarland University CIPMM , Building 48 66421 Homburg/Saar Germany jutta.engel@uni-saarland.de

Fajonyomi, Daniel Department of Pharmacology Faculty of Medicine & Dentistry University of Alberta 6-040 Li Ka Shing Centre Edmonton, Alberta, Canada fajonyom@ualberta.ca

Flockerzi, Veit Department of Experimental & Clinical Pharmacology & Toxicology Faculty of Medicine Saarland University University Hospital, Building 46 66424 Homburg/Saar Germany veit.flockerzi@uks.eu

Herrmann, Johannes Department of Cellular Biology Faculty of Biology University of Kaiserslautern Erwin-Schrödinger-Straße 13 67663 Kaiserslautern Germany hannes.herrmann@biologie.uni-kl.de

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Höring, Jonas Department of Molecular Biophysics Faculty of Biology University of Kaiserslautern Erwin-Schrödinger-Straße 13 67663 Kaiserslautern Germany jonashoering@gmx.de

John, Annalisa Department of Plant Physiology Faculty of Biology University of Kaiserslautern Erwin-Schrödinger-Straße 22 67663 Kaiserslautern Germany annalisajo93@gmail.com

Keller, Sandro Department of Molecular Biophysics Faculty of Biology University of Kaiserslautern Erwin-Schrödinger-Straße 13 67663 Kaiserslautern Germany sandro.keller@biologie.uni-kl.de

Khan, Azkia Department of Plant Physiology Faculty of Biology University of Kaiserslautern Erwin-Schrödinger-Straße 22 67663 Kaiserslautern Germany akhan@rhrk.uni-kl.de

Khandpur, Gurleen Kaur Department of Biochemistry Faculty of Medicine Saarland University Campus, Building B2.2 66123 Saarbrücken Germany gurleenkhandpur@gmail.com

Laborenz, Janina Department of Cellular Biology Faculty of Biology University of Kaiserslautern Erwin-Schrödinger-Straße 13 67663 Kaiserslautern Germany laborenz@rhrk.uni-kl.de

Lang, Sven Department of Medical Biochemistry & Molecular Biology Faculty of Medicine Saarland University University Hospital, Building 44 66424 Homburg Germany svenlang@t-online.de

Lemieux, Joanne Department of Biochemistry School of Translational Medicine Faculty of Medicine & Dentistry University of Alberta 451 Medical Sciences Building Edmonton, Alberta, Canada T6G 2H7 mlemieux@ualberta.ca

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Li, Xiaobing Department of Molecular & Cell Biology Faculty of Natural Sciences & Technology III Saarland University Campus Saarbrücken, Building A 1.5 P.O. Box 151150 66041 Saarbrücken Germany chnlixiaobing@gmail.com

Liu, Xiong Department of Physiology Faculty of Medicine & Dentistry University of Alberta 7-29A Medical Sciences Building Edmonton, Alberta Canada T6G 2H7 xiong4@ualberta.ca

Martins Rodrigues, Cristina Department of Plant Physiology Faculty of Biology University of Kaiserslautern Erwin-Schrödinger-Straße 22 67663 Kaiserslautern Germany cmrodri@rhrk.uni-kl.de

Möhlmann, Torsten Department of Plant Physiology Faculty of Biology University of Kaiserslautern Erwin-Schrödinger-Straße 22 67663 Kaiserslautern Germany moehlmann@biologie.uni-kl.de

Morgan, Bruce Department of Biochemistry Faculty of Medicine Saarland University Campus, Building B2.2 66123 Saarbrücken Germany bruce.morgan@uni-saarland.de

Neuhaus, Ekkehard Department of Plant Physiology Faculty of Biology University of Kaiserslautern Erwin-Schrödinger-Straße 22 67663 Kaiserslautern Germany neuhaus@rhrk.uni-kl.de

Niemeyer, Barbara Department of Biophysics Faculty of Medicine Saarland University University Hospital, Building 58 66424 Homburg Germany barbara.niemeyer@uks.eu

Oestreicher, Julian Department of Biochemistry Faculty of Medicine Saarland University Campus, Building B2.2 66123 Saarbrücken Germany jul.oe49@googlemail.com

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Philippar, Katrin Department of Plant Biology Faculty of Natural Sciences & Technology Saarland University University Hospital, Building A 2.4 66421 Homburg /Saar Germany katrin.philippar@uni-saarland.de

Prananingrum, Pratiwi Department of Plant Physiology Faculty of Biology University of Kaiserslautern Erwin-Schrödinger-Straße 22 67663 Kaiserslautern Germany pratiwi@rhrk.uni-kl.de

Ravichandran, Keerthana Department of Physiology Faculty of Medicine Saarland University CIPMM, Building 48 D-66421 Homburg Germany keerthu.gk@gmail.com

Rettig, Jens Department of Physiology Faculty of Medicine Saarland University CIPMM, Building 48 D-66421 Homburg Germany jrettig@uks.eu

Russo, Antonietta Department of Medical Biochemistry & Molecular Biology Faculty of Medicine Saarland University University Hospital, Building 44 66424 Homburg Germany russo.antonietta14@gmail.com

Sarder, Hasib Department of Molecular & Cell Biology Faculty of Natural Sciences & Technology III Saarland University Campus Saarbrücken, Building A 1.5 P.O. Box 151150 66041 Saarbrücken Germany sma.hasib@gmail.com

Saurette, Matthew Department of Pediatrics Division of Nephrology & Physiology University of Alberta 2B2.42 Walter Mackenzie Centre Edmonton, Alberta, Canada, T6G 2R7 saurette@ualberta.ca

Schepsky, Pauline Department of Biophysics Faculty of Medicine Saarland University CIPMM , Building 48 66421 Homburg/Saar Germany pauline.schepsky@uni-saarland.de

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Schmitt, Manfred Department of Molecular & Cell Biology Faculty of Natural Sciences & Technology III Saarland University Campus Saarbrücken, Building A 1.5 P.O. Box 151150 66041 Saarbrücken Germany mjs@microbiol.uni-sb.de

Schöppe, Mona Department of Biophysics Faculty of Medicine Saarland University University Hospital, Building 58 66424 Homburg Germany Mona.Schoeppe@uks.eu

Sicking, Mark Department of Medical Biochemistry & Molecular Biology Faculty of Medicine Saarland University Building 45.2 D-66421 Homburg/Saar Germany mark.sicking@gmx.de

Tirincsi, Andrea Department of Medical Biochemistry & Molecular Biology Faculty of Medicine Saarland University University Hospital, Building 44 66424 Homburg Germany tirincsi.andrea@gmail.com

Touret, Nicolas Department of Biochemistry School of Translational Medicine Faculty of Medicine & Dentistry University of Alberta 4-020H Katz Group-Rexall Centre for Pharmacy & Health Research Edmonton, Alberta, Canada T6G 2E1 touret@ualberta.ca

Van der Laan, Martin Department of Medical Biochemistry & Molecular Biology Faculty of Medicine Saarland University Building 45.2 D-66421 Homburg/Saar Germany Martin.van-der-laan@uks.eu

Vu, Duc Phuong Department of Plant Physiology Faculty of Biology University of Kaiserslautern Erwin-Schrödinger-Straße 22 67663 Kaiserslautern Germany phuong-vu@gmx.de

Wollweber, Florian

Department of Medical Biochemistry & Molecular Biology Faculty of Medicine Saarland University Building 45.2 D-66421 Homburg/Saar Germany florianwollweber@gmail.com

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Yadao, Nilam Department of Medical Biochemistry & Molecular Biology Faculty of Medicine Saarland University Building 45.2 D-66421 Homburg/Saar Germany nilam_yadao@hotmail.com

Zhou, Janet Department of Physiology School of Translational Medicine University of Alberta 7-10A Medical Sciences Building Edmonton, Alberta Canada T6G 2S2 jrzhou@ualberta.ca

Zimmermann, Richard Department of Medical Biochemistry & Molecular Biology Faculty of Medicine Saarland University University Hospital, Building 44 66424 Homburg Germany richard.zimmermann@uks.eu

Zöller, Eva Department of Cellular Biology Faculty of Biology University of Kaiserslautern Erwin-Schrödinger-Straße 13 67663 Kaiserslautern Germany zoeller@rhrk.uni-kl.de

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Hints

Location

Parkhotel Weiskirchen

Kurparkstraße 4

66709 Weiskirchen

Phone: +49 (0)6876-919-0

Fax: +49 (0)6876-919-519

E-Mail: info@parkhotel-weiskirchen.de

WWW: http://www.parkhotel-weiskirchen.de/

Conference phone

0151 18234824 (Gabi)

Taxi-Service

1. Taxi Martin (Wadern), 06871-2284

2. Taxi Martin (Weiskirchen), 06876-700750 (info@taximartin.de)

3. Taxi Fries, 06874-1392

4. Taxi Göbel, 06876-500 Airport-Shuttle Fahrservice Rosenberger (Lauterecken), 0170-8934702 Airport-Runner (Höringen), 0173-9112423

Venue

1. By train

From Homburg, Kaiserslautern or Saarbrücken by train to Merzig and then by bus

(Regionalbus R1, direction: Wadern) from Merzig to Weiskirchen (Kirche); total travel time

1.40 h to 2.10 h; for suitable train connections, please use the homepage of the “Deutsche

Bahn” (https://www.bahn.de/p/view/index.shtml)

2. By car

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