Final answer:
The dynamin protein helps detach a vesicle from the plasma membrane through a process called membrane scission.
Step-by-step explanation:
The dynamin protein plays a crucial role in detaching a vesicle from the plasma membrane through a process called membrane scission. When a vesicle is ready for detachment, dynamin assembles into a helical collar around the neck of the vesicle. Using the energy from GTP hydrolysis, dynamin constricts and pinches off the neck, releasing the vesicle into the cytoplasm.
For example, in clathrin-mediated endocytosis, the dynamin protein binds to the neck of the coated pit, where clathrin has assembled. As dynamin constricts, it facilitates the invagination of the coated pit, leading to the formation of a coated vesicle. Once the vesicle is fully formed, dynamin completes the scission by severing the neck, allowing the vesicle to detach from the plasma membrane.