Dephosphorylates proteins phosphorylated on Ser, Thr, and Tyr residues and low molecular weight phosphatase substrate para-nitrophenylphosphate. Phosphorylates phosphatidylinositol 3,4,5-trisphosphate (PIP3). H2O + O-phospho-L-tyrosyl-[protein] = L-tyrosyl-[protein] + phosphate Localized to perinuclear region. Expressed in brain, heart, kidney, spleen, liver, colon, testis, muscle, placenta, thyroid gland, pancreas, ovary, prostate, skin, peripheral blood, and bone marrow. Expressed in fetal brain and fetal liver. Belongs to the protein-tyrosine phosphatase family. Non-receptor class myotubularin subfamily.