Adapter protein that may provide indirect link between the endocytic membrane traffic and the actin assembly machinery. May regulate the formation of clathrin-coated vesicles (CCPs). Seems to be involved in CCPs maturation including invagination or budding. Involved in endocytosis of integrin beta-1 (ITGB1) and transferrin receptor (TFR). Plays a role in dendrite formation by melanocytes. Belongs to a complex that may contain multimers of ITSN1, ITSN2 and EPS15, and different partners according to the step in the endocytic process. Interacts with ADAM15. Interacts with FASLG (By similarity). Interacts with ANKRD54. Interacts with FCHO2. Widely expressed in adult tissues. Widely distributed throughout the adult forebrain. Prominent expression was observed in the neocortex, the piriform cortex, the pyramidal cell layers of hippocampus, the dentate gyrus, in several nuclei of the thalamus and hypothalamus and in the amygdala. It is uncertain whether Met-1 or Met-2 is the initiator. Truncated N-terminus.