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

General

membrane protein multisubunit protein

Properties

SIZE: MW = 180 kD COMPARTMENT: cellular membrane MOTIF: membrane region SUBUNITS: clathrin heavy chain (3) MOTIF: membrane region clathrin light chain (3) MOTIF: membrane region Ca+2-binding site

References

Textbook of Biochemistry with Clinical Correlations, 3rd ed., TM Devlin (ed), Wiley-Liss, NY 1992 pg 886

Components

clathrin heavy chain clathrin light chain