Final answer:
Active Rab proteins, or Rab-GTP, are involved in vesicle transport, while inactive Rab proteins, or Rab-GDP, are not able to interact with vesicles. Activation of Rab-GTP involves the exchange of GDP for GTP, allowing it to interact with vesicle coat proteins and other components of the transport machinery.
Step-by-step explanation:
Rab proteins are a family of small GTPases that play a crucial role in vesicle transport. The active form of Rab protein, Rab-GTP, is involved in the binding and transport of vesicles from one compartment to another within a cell. On the other hand, the inactive form of Rab protein, Rab-GDP, is not able to interact with vesicles and is not involved in vesicle transport. The activation of Rab protein involves the exchange of GDP for GTP, which is catalyzed by specific guanine nucleotide exchange factors (GEFs). The activation of Rab-GTP allows it to interact with vesicle coat proteins and other components of the transport machinery.