C-src Tyrosine Kinase

C-src tyrosine kinase, is a cytoplasmic tyrosine kinase protein encoded by the CSK gene. It includes an SH2 domain, an SH3 domain, and a tyrosine kinase domain. This protein phosphorylates a carboxyl-terminus tyrosine residue on human Src, which acts as a negative regulatory site. It may be recruited to membrane complexes by interactions of Csk's SH2 domain with phosphotyrosyl sites in membrane proteins.