Facilitator Questions

1. Why would an experimentalist bother to reconstruct vesicle budding in vitro (in a test tube) when vesicle budding can be readily observed in live cells? What are some of the advantages of using biochemical techniques to study the secretory pathway?

 

2. What types of proteins would you expect to be transported in COPII-coated vesicles? COPI-coated vesicles? Are any proteins transported regularly by both COPI- and COPII-coated vesicles?

 

3. Although various coat complexes exist, they tend to share basic functional characteristics. What would you expect some of these to be? (Hint: think about the roles of the various COPII components discussed in the lecture.)
4. Why might it be beneficial to the cell to have a variety of different coat complexes that each associate with a particular type of membrane?

 

5. What would you expect to happen if an in vitro COPII vesicle budding reaction was carried out in the presence of a nonhydrolyzable analog of GTP?