Binds to membranes enriched in phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2). May have a role in transport via clathrin-coated vesicles from the trans-Golgi network to endosomes. Stimulates clathrin assembly (By similarity). Binds clathrin heavy chain and AP-2 (By similarity). Interacts with VTI1B (By similarity). Interacts with GGA2 (via GAE domain) (By similarity). Interacts with AP1G1 (via GAE domain) (By similarity). Interacts with AP1G2 (via GAE domain) (By similarity). Found throughout the cell, with the exception of the cell surface. Concentrated in the perinuclear region and associated with clathrin-coated vesicles close to the trans-Golgi network (By similarity). Belongs to the epsin family.