CDCP1 (CUB-domain-containing protein 1) contains three extracellular CUB domains, a transmembrane domain and two putative cytoplasmic tyrosine phosphorylation sites. Phosphorylation of the gp140 and p80 proteins is mediated by Src family kinases at various tyrosine residues, including Tyr 734. PTP family members mediate the desphosphorylation of CDCP1. The conversion of gp140 to p80 prolongs the phosphorylation state, which may affect signaling in epithelial wounds. CDCP1 acts as a marker for hematopoetic cells and also exhibits high expression in metastatic colon and breast tumors.