Dephosphorylates proteins phosphorylated on Ser, Thr, and Tyr residues and low molecular weight phosphatase substrate para-nitrophenylphosphate. Phosphorylates phosphatidylinositol 3,4,5-trisphosphate (PIP3) (By similarity). H2O + O-phospho-L-tyrosyl-[protein] = L-tyrosyl-[protein] + phosphate Localized to perinuclear region. Belongs to the protein-tyrosine phosphatase family. Non-receptor class myotubularin subfamily.