Presentation By

Kate, Wisdom Deebekeon

Vesicle Tethering

ObjectiveTo understand the mechanism of Vesicle

Tethering.

Vesicle Tethering, what is it?

• Formation of physical links between v- and t-SNARES

• Formed before TRANS SNARE complex formation

• Aimed at promoting specificity between two membranes

• Growing number of factors involved now identified, all

recruited by Rab GTPase.

Tethering factors

Two broad classes of molecules identified:

a) Long coiled-coil proteins• Form homodimeric coiled-coils

• E.g. Uso1p (in yeast) and P115 (in mammals)

• Essential for tethering ER-derived vesicles

b) Multisubunit tethering complexes• 7 large conserved complexes proposed

• Initially identified in yeasts

• E.g. include exocyst, COG complex, TRAPP, etc.

– TRAPP-1 involved in ER-Golgi anterograde transport

Image from: Whyte, J. R. C. and S. Munro (2002). "Vesicle tethering complexes in membrane traffic." Journal of Cell Science 115(13): 2627-2637.

Summary• Vesicle tethering important for specific localisation of

transport vesicles on membranes

• Many factors involved have been identified and characterised

• Rab GTPase plays important role in Tethering factor recruitment

References:1. Whyte, J. R. C. and S. Munro (2002). "Vesicle tethering complexes in

membrane traffic." Journal of Cell Science 115(13): 2627-2637

2. Olkkonen, V. M. and E. Ikonen (2006). "When intracellular logistics fails -genetic defects in membrane trafficking." Journal of Cell Science 119(24): 5031-5045.

THANK YOU

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