Enables phosphatidylinositol 3-kinase regulator activity. Involved in early endosome to late endosome transport; regulation of cellular protein catabolic process; and regulation of phosphatidylinositol 3-kinase activity. Located in cytosol; early endosome membrane; and late endosome membrane. Is extrinsic component of endosome membrane. [provided by Alliance of Genome Resources, Apr 2022]