week 6 - Principles of vesicle transport

Question 1

What are the essential components for all transport vesicle formation?

Answer 1

Coat, adaptor proteins, and GTPase.

• the adaptor protein is to recognise cargo

Question 2

What is the role of GEFs? (guanine nucleotide exchange factors)

Answer 2

GEFs turn of sigalling by allowing the exchange of GDP to GTP.

Question 3

What is the role of GAPs? (GTPase Activating Proteins)

Answer 3

GAPs terminate signalling by introducing GTP hydrolysis.

Question 4

What are the components of COPII?
- name the GTPase, adaptor protein and the coat.

Answer 4

GTPase: Sar 1

Adaptor protein: Sec23/24

Coat: Sec13:31

–> the GEF is sec12
–> needed presence of ATP and GTP.

Question 5

What are adaptor proteins important?

Answer 5

They are needed to recognise the cargo and needed for the coat to be recruited.

Question 6

What are the steps involved in forming a COPII vesicle?

Answer 6

1. GEF for Sar1 exchanges GDP to GTP.
2. Adaptor complex can then be recruited.
3. in the adaptor: The Sec23 binds to Sar1 and Sec24 binds to cargo
4. The adaptor complex allows the outer protein coat to be recruited.

Question 7

what needs to happen to the coat before fusion?

Answer 7

The coat needs to be removed for fusion to occur?

If the coat is not removed, secretion is blocked, vesicles cant fuse with the target and deliver the cargo.

Question 8

What is the role of the coat?

Answer 8

It provides a structural scaffold and rigidity.