Final answer:
The GTPases involved in vesicle budding and uncoating include ARF and Sar1, making option d (a and c) the correct answer.
Step-by-step explanation:
The GTPases involved in vesicle budding and the uncoating of vesicles released from the donor membrane include ARF and Sar1. Therefore, the correct answer to which GTPases are involved would be d. a and c. ARF is a GTPase that is involved in the budding of vesicles from the Golgi apparatus, whereas Sar1 is involved in the budding of COPII-coated vesicles from the endoplasmic reticulum. Both of these proteins are crucial for vesicle formation, transport, and uncoating in the cellular vesicle traffic system.
These GTPases play key roles in the process of vesicle formation and fusion. ARF is involved in coat protein formation, Rab is involved in vesicle tethering and fusion, and Sar1 is involved in COPII coat formation. Each of these GTPases is essential for the efficient transport of cargo proteins from one cellular compartment to another.