Clathrin, Light Polypeptide A (CLTA)

Clathrin is the main structural component of the lattice covering the cytoplasmic face of the coated pits and coated vesicles in which specific macromolecules are entrapped in the process of receptor-mediated endocytosis. Clathrin is a large, soluble protein composed of heavy chains (molecular size, about 192 kD) and light chains (molecular size, about 32 to 38 kD). Two major classes of clathrin light chains, referred to as LCA (encoded by the CLTA gene) and LCB (encoded by CTLB), have been identified. The clathrin unit that assembles into coats has 3 extended legs, 500 angstroms in length, splayed out in a pinwheel-like structure (triskelion). Each of the legs is built from a single heavy chain, with a light chain bound to each proximal segment. At least 4 distinct forms of clathrin light chains are found in mammalian cells.