Binds specifically to phosphatidylinositol 3,4-diphosphate (PtdIns3,4P2), but not to other phosphoinositides. May recruit other proteins to the plasma membrane (By similarity). Interacts with MPDZ and PTPN13. Locates to the plasma membrane after treatments that stimulate the production of PtdIns3,4P2. Binds to membranes enriched in PtdIns3,4P2 via the C-terminal PH domain.