Clathrin
Clathrin is a protein heavily involved in the creation of coated vesicles, it also allows for the trafficking inside cell pathways, mechanisms and regulation. It forms a polyhedral (soccer-ball-shaped) lattice made up of many clathrin molecules that coats a new vesicle as it forms and also helps in protein sorting[1].
Vesicles do not form spontaneously, but rather, are facilitated by coat-proteins like clathrin. Clathrin doesn't bind directly to a membrane to form vesicles; instead, it binds to adaptor proteins that recognize molecules on a membrane surface. At least 20 different clathrin adaptors have been identified, each recognizing and binding to membrane proteins and phospholipids that are unique to a particular organelle[2].
During vesicle transport, cargo-loaded vesicles form at a donor compartment, with the help of the specialised clathrin coat. It is one of three types of coating.
Clathrin-dependent endocytosis is the process by which cells undergo endocytosis by the inward budding of plasma membrane[3].