What GTP-binding protein plays a regulatory role by initiating vesicle formation and by regulating the assembly of the vesicle's COPII coat?
A)Sar1
B)Gar1
C)ARF1 (adenosylation ribose factor)
D)Ras
E)Src

Question

Quizplus · Accepted Answer

Sar1 is a small GTP-binding protein that plays a regulatory role in intracellular vesicle trafficking. It initiates the formation of vesicles by binding to the ER membrane and recruiting COPII coat proteins. Sar1 also regulates the assembly of the COPII coat by undergoing a conformational change upon GTP hydrolysis, which triggers the recruitment of additional coat proteins. Thus, Sar1 is essential for the formation of COPII-coated vesicles that transport secretory cargo from the ER to the Golgi apparatus.

What GTP-Binding Protein Plays a Regulatory Role by Initiating Vesicle