| Here we show that CEACAM 1 is a substrate of the EGFR and that upon being phosphorylated , CEACAM 1 reduces EGFR mediated growth of transfected Cos 7 and MCF 7 cells in response to EGF . ^^^ Using transgenic mice overexpressing a phosphorylation defective CEACAM 1 mutant in liver ( L SACC 1 ) , we show that the effect of CEACAM 1 on EGF dependent cell proliferation is mediated by its ability to bind to and sequester Shc , thus uncoupling EGFR signaling from the ras / MAPK pathway . ^^^ In L SACC 1 mice , we also show that impaired CEACAM 1 phosphorylation leads to ligand independent increase of EGFR mediated cell proliferation . ^^^ CEACAM 1 modulates epidermal growth factor receptor mediated cell proliferation . ^^^ |