Enables phosphatidylinositol phosphate binding activity; phosphatidylinositol-3,4-bisphosphate binding activity; and retromer complex binding activity. Involved in several processes, including endosomal transport; negative regulation of barbed-end actin filament capping; and regulation of substrate adhesion-dependent cell spreading. Located in cytosol; early endosome; and nucleolus. Part of WASH complex. [provided by Alliance of Genome Resources, Apr 2022]