Tethering Docking and Fusion Flashcards
What kind are the 2 kinds of tether factors?
- Long coiled-coil
- Multi-subunit proteins
What is the function of tether proteins?
- Co-operate with Rab GTPases to mediate specific targeting of vesicles
- Can bridge between 2 organelles
Where do multi-subunit tether operate?
Throughout the endcytic and secretory pathways
Give examples of tether factors
- TRAPPI
- TRAPPII
- HOPS
TRAPP1 complex is a GEF for what?
YptI/Rab1
What does RabI recruit?
p115 a coiled-coil tether which interacts with other tethers on the vesicle and helps initaite co-protein disassembly
What does p115 do in vesicle delivery?
- Brings vesicle closer and allows TRAPPI to bind to components of COPII coat
- 2 compartments are brought into close proximity
In vesicle delivery what does interaction between TRAPPI and sec23 lead to?
Leads to SNARE proteins pairing and membrane fusion
What are the 2 classes of SNARE proteins?
- v-SNAREs
- t-SNAREs
Where are v-SNAREs located?
On vesicle membrane
Where are t-SNAREs located?
On target membrane
What is the structure of v-SNAREs?
Usually single polypeptide
What is the structure of t-SNAREs?
Usually 3 polypeptides
What are the 2 means of selectivity in tethering, docking, and fusion of proteins?
- Tether proteins
- Highly specific pairing between v and t SNAREs
What structure does the interaction of v-SNAREs and t-SNAREs produce?
Coiled-coil structure
