SIRT6 and the disease of aging

Mark Devries

Outline

• Background– Sirtuin biology– SIRT6 role in aging

• Results – Phylogeny– Protein domains– Phenotype– DNA motifs– Possible protein modifications– Chemical activators– Protein interactions

• Future directions

FunctionHistone Deacetylases (HDAC)• Class I and II

– Zinc dependant deacetylase

• Class III

– NAD+ dependant deacetylase

– SIRT6 has deacetylase activity (Du et al., 2009)

Sirtuin Family

SIRT6 Protein

• 355 AA protein

• localizes to nucleus

• Interacts NF-kB (Kawahara et al., 2008) and deacetylates H3K9 (Michishita et al., 2008)

SIRT 6 phenotype

Mostoslavsky et al 2006

Phenotype

• Shorter lifespan

• Genomic instability

What are the signs SIRT6 leads to aging phenotype?

• Increase expression of aging genes

• Decreased IGF-1 levels

• Increased genomic instability

• Other signs of aging related disease

My findings on SIRT6

Phylogeny

T-Coffee

Protein domain

• Sirtuin domain– Rossman fold– Cystine residues

Picture retrieved from www.topsan.org

Phenotype

DNA motifs

Possible protein modifications

Protein modifications

Chemical

• No inhibitors or activators

• Resveratrol an activator?

• Room for discovery

How much resveratrol does it take to activate Sirtuins?

•200uM concentration usually for activation •Which equal 1.824g of resveratrol• 12,160 glasses of wine

Protein interaction

Summary

• Numerous DNA motifs ( Myc, Rel, MZF1)

• Many sites of phosphorlation/ Sumoylation

• No known activators or inhibitors

• Possible interaction with ELF5

Future directions• Co-immunoprecipitation for interaction with

ELF5

• MS to see if SIRT6 is modified

• Western blots to determine if sumolated

• Chemical library screens to determine new inhibitors and activators

References Michishita, E., McCord, R.A., Berber, E., Kioi, M., Padilla-Nash, H., Damian, M., Cheung, P.,

Kusumoto, R., Kawahara, T.L., Barrett, J.C., et al. (2008). SIRT6 is a histone h3 lysine9 deacetylase that modulates telomeric chromatin. Nature 452, 492-496. doi:10.1038/nature06736

Mostoslavsky, R., Chua, K.F., Lombard, D.B., Pang, W.W., Fischer, M.R., Gellon, L., Liu, P., Mostoslavsky, G., Franco, S., Murphy, M.M., et al. (2006). Genomic instability and aging like phenotype in the absence of mammalian SIRT6. Cell 124, 315-329. doi:10.1016/j.cell.2005.11.044

Kawahara, T.L., Michishita, E., Adler, A.S., Damian, Mara., Berber, E., Lin, Meihong., McCord, R.A., Ongaigui, K.C., Boxer, L.D., Chang, H.Y., Chua, K.F. (2008). SIRT6 links histone H3 lysine 9 deacetylation to NF-kB-dependent gene expression and organismal life span. Cell 136, 62-74. doi: 10.1016/j.cell.2008.10.052

Sauve A.A., Celic I., Avalos J., Deng H., Boeke J.D., Schramm V.L. (2001). Chemistry of gene silencing: the

mechanism of NAD+-dependent deacetylation reactions. Biochemistry 40:15456-15463 doi: 10.1021/bi011858j

Dutnail, R.N., Pillus, L. (2001). Deciphering NAD-Dependent Deacetylases. Cell 105, 161-164. doi:10.1016/S0092-8674(01)00305-1