c-Src (proto-oncogene tyrosine-protein kinase Src) is a 60 kD tyrosine protein kinase family containing both SH2 and SH3 domains. c-Src is expressed at high levels in differentiated cells including neurons, platelets, macrophages, many tumors. c-Src is a lipid-modified signaling molecule (myristolyated) involved in cell-cell interactions, cell migration, and proliferation through the phosphorylation of many substrates including beta-catenin, paxillin, and vinculin. Phosphorylation of c-Src on Tyr-526 by Csk (c-Src kinase) represses activity; c-Src is activated by phospholipase D, insulin-like growth factor receptor, EGF-receptor, fibroblast growth factor receptor, and prolactin receptor binding. c-Src has been shown to be phosphorylated on multiple sites and to interact with polyoma virus middle T antigen, PYK2, HSP72, and caveolin. The Poly6054 antibody recognizes the N-terminal region of human and mouse c-Src and has been shown to be useful for Western blotting.