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 actin and this stimulates phosphatase activity. Also interacts with LIMK1 and 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. Also recruited to actin rich membrane protrusions such as lamellipodia, which may allow local control of actin dynamics at sites of cell locomotion. Also localized to the cleavage furrow and the midbody during cytokinesis. Phosphorylated. Inhibitory phosphorylation by PAK4 promotes binding to YWHAZ. Phosphorylation at Ser-978 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. Tyrosine phosphatase activity has not been demonstrated for this protein to date. May be produced at very low levels due to a premature stop codon in the mRNA, leading to nonsense-mediated mRNA decay. Due to intron retention. Belongs to the protein-tyrosine phosphatase family. Extended N-terminus.