Has a role in early neural and epidermal development; neuroblast movements during closure of the gastrulation cleft and epidermal morphogenesis. Vab-1 and ptp-3 may function redundantly within the same sets of neuronal precursors. H2O + O-phospho-L-tyrosyl-[protein] = L-tyrosyl-[protein] + phosphate Both isoforms are ubiquitously expressed in early embryos. In later embryos, larvae and adults expression is highest in the nerve ring, dorsal cord, ventral cord and epithelial tissues. Belongs to the protein-tyrosine phosphatase family. Receptor class 2A subfamily.