clathrin (triskelion)

Function

• endocytosis of receptor-ligand complexes involves invagination of coated pits into the cytoplasm & pinching off of these invaginations to form coated vesicles containing the receptor-ligands
• clathrin is the major protein of the polyhedral coat of coated pits & vesicles; the coated vesicle contains 70% clathrin
• immediately after clathrin-coated pits pinch off from the cell membrane to form clathrin-coated vesicles, clathrin dissociates from the vesicles & the vesicles fuse to form receptosomes
• two different adapter protein complexes link the clathrin lattice either to the plasma membrane or to the trans-Golgi network
• clathrin triskelions, composed of 3 heavy chains & 3 light chains, are the basic subunits of the clathrin coat
• in the presence of light chains, hub assembly is influenced by both the pH & the concentration of Ca+2

Compartment

• cytoplasmic vesicle membrane
• peripheral membrane protein; cytoplasmic side
• coated pit
• cytoplasmic face of coated pits & vesicles

More general terms

• membrane protein
• multisubunit protein

Additional terms

• clathrin adaptor (assembly) protein