What is the role of clathrin in vesicle formation?

Clathrin plays a crucial role in the processes of endocytosis and vesicle trafficking within cells, particularly in the formation of transport vesicles that bud off from the membrane. Clathrin molecules assemble into a basket-like structure on the cytoplasmic side of the membrane, facilitating the invagination of the membrane. This invagination creates a budding structure that eventually pinches off to form a vesicle.

The formation of this clathrin-coated vesicle ensures that specific cargo, such as proteins and lipids, are encapsulated and transported to their appropriate destinations, such as the endosomes or lysosomes. The clathrin coat is ultimately shed after the vesicle is formed, allowing for the fusion of the vesicle with target membranes and the delivery of the cargo therein. This mechanism is vital for maintaining cellular homeostasis and facilitating communication between different cellular compartments.