Probable phosphatase with dual specificity toward Ser/Thr and Tyr-containing proteins (By similarity). Dephosphorylates pNPP, in vitro. Essential for proper regulation of erkB (erk2) and optimal motility during development. 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 Expressed (at protein levels). Up-regulated upon starvation, reaching a maximum around 10 hours. Expression subsequently declined but is present throughout development. Cells result in higher prestimulus and persistent stimulation erkB phosphorylation upon cAMP stimulation, display strong defects in motility, and more rapid cAMP production. Cells fail to display aggregates, fruiting bodies, fail to form territorial streams and are defective in cell migration (absence of random and directional migration) and in chemotaxis. Belongs to the protein-tyrosine phosphatase family. Non-receptor class dual specificity subfamily.