Endocytic Proteins

Question 1

What is adaptor protein AP2?

Answer 1

An adaptor protein for clathrin coated vesicles
Has an alpha and beta subunit

Question 2

What are Rab GEFs?

Answer 2

Activate Rabs. (RabGDP ~> RabGTP)

Question 3

What are Rab GAPs?

Answer 3

Deactivate Rabs. (RabGTP ~> RabGDP)

Question 4

What do Rabs help to do?

Answer 4

• Recycle vesicles back to membrane
• Transport cargo
• Aid fusion of vesicles

Question 5

How do Rabs work in vesicle fusion?

Answer 5

RabGTP fuses to vesicle.
Vesicle moves to target membrane, RabGTP binds to Rab effector, SNAREs bind, vesicle fuses to membrane.
Rab GAPs hydrolyse GTP and remove RAB from vesicle
GDI extracts Rab.

Question 6

What other than GTP can activate Rabs?

Answer 6

The effector of one Rab can activate the next.

Question 7

What does mutation of Sec23 cause?

Answer 7

CLSD, due to COPII coat not forming

Question 8

How is large cargo packaged into COPII vesicles?

Answer 8

Large cargo such as collagen cannot fit into COPII vesicles.
Accessory proteins rearrange COP II components and form a tunnel for collagen to move through.

Question 9

What does a mutation of REP1 cause?

Answer 9

Choroidermia (blindness in men)

Question 10

What does mutation in Rab27a cause?

Answer 10

Griscelli syndrome (albino)

Question 11

What does mutation in Rab7 cause?

Answer 11

CMT disease