Lecture 12

Question 1

Exocyst Tethers?

Answer 1

Traffic from the golgi to the PM

Question 2

CORVET/HOPS?

Answer 2

Important for endosomes

Question 3

What holds the two proteins at the PM for exocyst?

Answer 3

PIPs

Question 4

Lysosome?

Answer 4

macromolecules get broken down into their constitutive parts either for metabolism or just to be broken down

Question 5

Which Rabs do CORVET/HOPS bind?

Answer 5

CORVET: Rab5
HOPS: Rab7

Question 6

Two types of SNAREs?

Answer 6

V-type: SNAREs on vesicles
T-type: SNAREs on the target membrane

Question 7

V and T SNAREs?

Answer 7

After uncoating and once the vesicle is near the target a specific v-SNARE will interact with a t-SNARE on the target compartment and this will allow the fusion to occur. Form a stable tetramer

Question 8

V-SNAREs?

Answer 8

-Monomers
-Transmembrane proteins with a single pass transmembrane domain and a part that sticks out into the cytoplasm

Question 9

T-SNAREs?

Answer 9

-Trimers
-Combination of transmembrane subunits and peripheral subunits

Question 10

V-snare folding?

Answer 10

v-SNARE coming off of the vesicle is very unstructured and not folded
(unstable)

Question 11

T-SNARE folding?

Answer 11

t-SNARE is partially folded and partially stable

Question 12

V and T SNARE folding?

Answer 12

-Fold into a stable complex
-Energetically favourable 4-helix bundle to bring the vesicle and membrane close together
-No ATP/Energy

Question 13

Homotypic Fusion ?

Answer 13

Fusion events where the donor membrane is identical to the target membrane

Question 14

Homotypic Fusion example?

Answer 14

1. COP II vesicles to form the cis cisternae
2. Small endosomes can fuse during maturation
3. Cell division organelles are fragmented then put back together

Question 15

Homotypic fusion

Answer 15

V and T SNAREs are identical and must be pulled apart by NSF to allow for further fusion