Involved in endocytosis and intracellular vesicle trafficking, both during interphase and at the end of mitosis. Required for efficient progress through mitosis and cytokinesis. Required for normal formation of the cleavage furrow at the end of mitosis. Plays a role in endocytosis via clathrin-coated pits, but also clathrin-independent, actin-dependent fluid-phase endocytosis. Plays a role in macropinocytosis. Binds to membranes enriched in phosphatidylinositol 4,5-bisphosphate and promotes membrane tubulation. Stimulates the GTPase activity of DNM2. Promotes DNM2 location at the plasma membrane. Together with DNM2, involved in autophagosome assembly by regulating trafficking from recycling endosomes of phospholipid scramblase ATG9A. Heterodimer with SNX9. Interacts with ITCH. Interacts with dynamin-2 (DNM2), SYNJ1 and WASL. Interacts with the AP-1 complex (By similarity). Interacts with FCHSD1 (via the F-BAR domain) (PubMed:26567222). Localized at sites of endocytosis at the cell membrane. Detected on newly formed macropinosomes. Partially colocalized with clathrin and dynamin at the cell membrane. Transiently recruited to clathrin-coated pits at a late stage of clathrin-coated vesicle formation. The PX domain mediates interaction with membranes enriched in phosphatidylinositol 4,5-bisphosphate. Belongs to the sorting nexin family.