Following protein biogenesis, proteins are trafficked to different cellular compartments within the cell from either the endoplamsic reticulum, or (mostly) the golgi apparatus. This assessed presentation was delivered to a group of fellow students during the stage 2 (in April 2013) of my studies.

1. Presentation
By
Kate, Wisdom Deebeke
on
Vesicle Tethering
Objective
To understand the mechanism of Vesicle
Tethering.

2. 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.

3. 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.

4. 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.

5. THANK YOU
FOR YOUR ATTENTION
ANY QUESTIONS...?