Required in all receptor tyrosine kinase signaling pathways. Functions downstream of the receptor tyrosine kinase torso, acting in concert with D-Raf via tailless. Also functions downstream of Egfr (epidermal growth factor receptor) and btl (fibroblast growth factor receptor). The SH2 domain suggests that csw effects its role by mediating heteromeric protein interactions. Maternally required for normal determination of cell fates at the termini of the embryo. Required for cell fate specification of the ventral ectoderm, in the developing embryonic CNS and for embryonic tracheal cell migration. Functions during imaginal development for proper formation of adult structures such as eyes, aristae, L5 wing vein and the tarsal claw. Dephosphorylates drpr isoform A which is required for the inhibition by drpr isoform A of glial cell engulfment of axonal debris produced following axonal injury (PubMed:22426252). H2O + O-phospho-L-tyrosyl-[protein] = L-tyrosyl-[protein] + phosphate Interacts with drpr isoform A. Experimental confirmation may be lacking for some isoforms. Expressed uniformly throughout all tissues during embryogenesis. Expressed throughout development. RNAi-mediated knockdown in glia results in significantly reduced inhibitory activity of drpr isoform A on glial cell engulfment of axonal debris. The PTPase domain is interrupted by a PTPase insert which shares no homologies with other PTPase proteins. This PTPase insert is reminiscent of the kinase insert within the kinase catalytic domains of several receptor tyrosine kinases. Belongs to the protein-tyrosine phosphatase family. Non-receptor class subfamily.