Involved in endocytosis and intracellular vesicle trafficking, both during interphase and at the end of mitosis (PubMed:20427313, PubMed:18411244, PubMed:21048941, PubMed:22718350). Required for efficient progress through mitosis and cytokinesis (PubMed:22718350). Required for normal formation of the cleavage furrow at the end of mitosis (PubMed:22718350). Plays a role in endocytosis via clathrin-coated pits, but also clathrin-independent, actin-dependent fluid-phase endocytosis (PubMed:20427313). Plays a role in macropinocytosis (PubMed:21048941). Binds to membranes enriched in phosphatidylinositol 4,5-bisphosphate and promotes membrane tubulation (PubMed:18411244). Stimulates the GTPase activity of DNM2 (PubMed:20427313). Promotes DNM2 location at the plasma membrane (PubMed:20427313). Together with DNM2, involved in autophagosome assembly by regulating trafficking from recycling endosomes of phospholipid scramblase ATG9A (PubMed:29437695). Heterodimer with SNX9 (PubMed:20427313). Interacts with ITCH (PubMed:20491914). Interacts with dynamin-2 (DNM2), SYNJ1 and WASL (PubMed:20427313, PubMed:29437695). Interacts with the AP-1 complex (PubMed:18411244). Interacts with FCHSD1 (via the F-BAR domain) (By similarity). Localized at sites of endocytosis at the cell membrane (PubMed:18411244). Detected on newly formed macropinosomes (PubMed:21048941). Partially colocalized with clathrin and dynamin at the cell membrane (PubMed:20427313). Transiently recruited to clathrin-coated pits at a late stage of clathrin-coated vesicle formation (PubMed:18411244). The PX domain mediates interaction with membranes enriched in phosphatidylinositol 4,5-bisphosphate. Belongs to the sorting nexin family.