Clathrin is the major protein of the polyhedral coat of coated pits and vesicles. Clathrin coats are formed from molecules containing 3 heavy chains and 3 light chains. Cytoplasmic face of coated pits and vesicles. Localized to punctae scattered within the cytoplasm, along the plasma membrane and concentrated in the perinuclear region. Localizes to the posterior plasma membrane in cells which retract their tails when moving forward or changing direction. Recruited to the plasma membrane under the tight cap of cross-linked receptors prior to internalization of the capped ligand. Does not localize to the plasma membrane during phagocytosis. Expressed at highest levels in vegetatively growing cells. Expression declines during development. 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). Cells display lacks of coated pits, lacks of coated vesicles and large translucent vesicles that serve as endosomes and contractile vacuoles, and displays impaired macropinocytosis and osmoregulation defects. Phagocytosis is normal in loss-of-function mutant. Mutants lacking chcA show defects in the regulation of pseudopod formation, uropod stability, cell polarity and chemotaxis, and stream and aggregate more slowly than wild-type cells in response to starvation. Late development is impaired in mutants lacking chcA which show defects in prestalk and prespore cell patterning, and spore cells fail to differentiate. Mutants lacking chcA display defects in the sorting of precursor hydrolases from the constitutive secretory pathway to the lysosomal pathway, and reduced secretion of mature alpha-mannosidase from the lysosome to the extracellular space. Mutants lacking chcA fail to undergo cytokinesis in suspension culture due to the failure to assemble a functional contractile ring. Belongs to the clathrin heavy chain family.