Clathrin is the major protein of the polyhedral coat of coated pits and vesicles. Clathrin triskelions, composed of 3 heavy chains and 3 light chains, are the basic subunits of the clathrin coat (By similarity). Interacts with sau (PubMed:24786584). Cytoplasmic face of coated pits and vesicles. The C-terminal third of the heavy chains forms the hub of the triskelion. This region contains the trimerization domain and the light-chain binding domain involved in the assembly of the clathrin lattice. The N-terminal seven-bladed beta-propeller is formed by WD40-like repeats, and projects inward from the polyhedral outer clathrin coat. It constitutes a major protein-protein interaction node (By similarity). Belongs to the clathrin heavy chain family.