Probable tyrosine protein kinase which plays a role in vulva development, probably by acting as a negative regulator of the let-23/EGFR and let-60/ras pathway. Involved in the negative regulation of germline development (PubMed:14657502). ATP + L-tyrosyl-[protein] = ADP + H(+) + O-phospho-L-tyrosyl-[protein] ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] RNAi-mediated knockdown in a gap-1 mutant background causes a hyperinduction of the vulva in 60 percent of animals (PubMed:10949028). In addition, suppresses the slow germline development of clk-1 mutants (PubMed:14657502). Belongs to the protein kinase superfamily. Tyr protein kinase family.