Protein phosphatase which regulates actin filament dynamics. Dephosphorylates and activates the actin binding/depolymerizing factor cofilin, which subsequently binds to actin filaments and stimulates their disassembly. Inhibitory phosphorylation of cofilin is mediated by LIMK1, which may also be dephosphorylated and inactivated by this protein. H2O + O-phospho-L-tyrosyl-[protein] = L-tyrosyl-[protein] + phosphate H2O + O-phospho-L-seryl-[protein] = L-seryl-[protein] + phosphate H2O + O-phospho-L-threonyl-[protein] = L-threonyl-[protein] + phosphate Interacts with the 14-3-3 proteins YWHAB, YWHAG, YWHAQ, and YWHAZ. Interaction with 14-3-3 proteins inhibits phosphatase activity and also blocks recruitment to lamellipodia and stimulation by actin (By similarity). Interacts with actin and this stimulates phosphatase activity. Interacts with LIMK1. Localized to the cleavage furrow and the midbody during cytokinesis (By similarity). Also colocalizes with F-actin in the cytoplasm and the cell periphery, which may allow local control of actin dynamics at sites of cell locomotion. Expressed in brain, heart, kidney and thymus. Also expressed at lower levels in liver, skeletal muscle, small intestine and spleen. Ubiquitously expressed in the embryo at 14.5 dpc. Phosphorylated. Inhibitory phosphorylation by PAK4 promotes binding to YWHAZ. Phosphorylation at Ser-970 is decreased by stimuli which promote actin reorganization and lamellipodia formation. Can be dephosphorylated and activated by PPP3CA/calcineurin A. Phosphorylation decreases immediately prior to telophase (By similarity). Tyrosine phosphatase activity has not been demonstrated for this protein to date. Belongs to the protein-tyrosine phosphatase family.