Final answer:
The GTP-binding protein responsible for the release of clathrin-coated vesicles during endocytosis is dynamin. Dynamin's role is to facilitate the pinching off of the vesicle from the plasma membrane via GTP hydrolysis.
Step-by-step explanation:
The GTP-binding protein responsible for the release of a clathrin-coated vesicle from the plasma membrane during endocytosis is dynamin.
Dynamin is necessary for the final scission of clathrin-coated vesicles from the plasma membrane. In the process of receptor-mediated endocytosis, clathrin plays an essential role in the formation of coated pits that invaginate to form clathrin-coated vesicles. Clathrin, along with adaptor proteins like AP1, facilitates the clustering of integral membrane proteins which bind to specific cargo molecules. Once the coated pits have gathered their cargo and are fully invaginated, dynamin is recruited to the neck of the budding vesicle where it facilitates the pinching off of the vesicle from the membrane by using the energy derived from GTP hydrolysis. The clathrin-coated vesicles then carry their contents to various cellular compartments.
It’s worth noting that other proteins such as COP, V-SNARE, and T-SNARE also play important roles in vesicle budding and fusion with target membranes, but dynamin is specifically required for clathrin-coated vesicle scission during endocytosis.