Open AccesshCEACAM1‐4L downregulates hDAF‐associated signalling after being recognized by the Dr adhesin of diffusely adhering Escherichia coli
Author(s) -
Rougeaux Clémence,
Berger Cédric N.,
Servin Alain L.
Publication year - 2008
Publication title -
cellular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.542
H-Index - 138
eISSN - 1462-5822
pISSN - 1462-5814
DOI - 10.1111/j.1462-5822.2007.01072.x
Subject(s) - biology , dephosphorylation , bacterial adhesin , phosphatase , phosphorylation , proto oncogene tyrosine protein kinase src , downregulation and upregulation , microbiology and biotechnology , protein phosphatase 1 , protein tyrosine phosphatase , kinase , tyrosine phosphorylation , escherichia coli , biochemistry , gene
Summary Human decay accelerating factor (hDAF, CD55) and members of the c arcino e mbryonic‐ a ntigen‐related c ell‐ a dhesion m olecules (hCEACAMs) family are recognized as receptors by Gram‐negative, diffusely adhering Escherichia coli (DAEC) strains expressing Afa/Dr adhesins. We report here that hCEACAM1‐4L has a key function in downregulating the protein tyrosine Src kinase associated with hDAF signalling. After infecting HeLa epithelial cells stably transfected with hCEACAM1‐4L cDNA with Dr adhesin‐positive E. coli , the amount of the pTyr 416 ‐active form of the Src protein decreased, whereas that of the pTyr 527 ‐inactive form of Src protein did not increase. This downregulation of the Src protein implies that part of the hCEACAM1‐4L protein had been translocated into lipid rafts, the protein was phosphorylated at Tyr residues in the cytoplasmic domain, and it was physically associated with the protein tyrosine phosphatase, SHP‐2. Finally, we found that the hCEACAM1‐4L‐associated SHP‐2 was not phosphorylated and lacked phosphatase activity, suggesting that the downregulation of Src protein associated with hDAF signalling results from the absence of dephosphorylation of the pTyr 527 ‐inactive form necessary for Src kinase activation.