Non-receptor protein tyrosine phosphatase required for maintaining Dock in its non-phosphorylated state. H2O + O-phospho-L-tyrosyl-[protein] = L-tyrosyl-[protein] + phosphate Associates with the membranes of the reticular network and the mitochondria. Expressed during oogenesis and embryogenesis. Isoform A and isoform B are expressed in distinct patterns. Isoform B is expressed in the mesoderm and neuroblast layer during germband extension and later in the gut epithelia. Isoform A accumulates in 16 segmentally repeated stripes in the ectoderm during germband extension. These stripes are flanked by, and adjacent to, the domains of engrailed and wingless gene expression in the anterior/posterior axis. In stage 10 embryos, isoform A colocalizes with the area lateral to the denticle belts that will give rise to naked cuticle. Isoform A is also expressed later in embryogenesis in the central nervous system. Belongs to the protein-tyrosine phosphatase family. Non-receptor class 1 subfamily.