If Sar1 is inserted into the membrane:

Question

Quizplus · Accepted Answer

Sar1 specifically binds to GTP when it is inserted into the membrane, which triggers the recruitment of COPII coat proteins. The COPII coat proteins then form a vesicle around the cargo proteins, allowing them to be transported to the Golgi apparatus. Therefore, option A is the correct choice as Sar1 binds to GTP and recruits COPII coat proteins. Option B and C are incorrect because they have incorrect binding states or functions for Sar1, while option D is incorrect because Sar1 does indeed bind to GTP when it is inserted into the membrane.

If Sar1 Is Inserted into the Membrane