Plays a role in phosphate homeostasis. Mediates phosphate export from the cell. Binds inositol hexakisphosphate (Ins6P) and similar inositol polyphosphates, such as 5-diphospho-inositol pentakisphosphate (5-InsP7); these are important intracellular signaling molecules (By similarity). Potential receptor for xenotropic and polytropic murine leukemia retroviruses.