Phosphatase that acts on lipids with a phosphoinositol headgroup (PubMed:11676921). Has phosphatase activity towards phosphatidylinositol 3-phosphate and phosphatidylinositol 3,5-bisphosphate (PubMed:11676921). May also dephosphorylate proteins phosphorylated on Ser, Thr, and Tyr residues (PubMed:10733931).