title: The epidermal growth factor receptor tyrosine kinase phosphorylates connexin32.
abstract: The epidermal growth factor (EGF) receptor purified by calmodulin-affinity chromatography from solubilized rat liver plasma membranes phosphorylates connexin32 in gap junction plaques isolated from the same origin. Phosphorylation of connexin32 was stimulated by EGF and mainly occurs at tyrosine residue(s), although phosphorylation of serine and threonine residues was also detected. The kinetics parameters for the phosphorylation of connexin32 parallel those for the transphosphorylation of the EGF receptor. m-Calpain proteolyzes phosphoconnexin32, and its major 26 kDa proteolytic fragment only contains phosphotyrosine residue(s). Calmodulin binds to connexin32 in the absence of calcium and prevents in great extent its phosphorylation by the EGF receptor tyrosine kinase.
authors.affiliation: Instituto de Investigaciones Biomédicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain.
authors.forename: J A
authors.initials: JA
authors.lastname: Díez
authors.forename: M
authors.initials: M
authors.lastname: Elvira
authors.forename: A
authors.initials: A
authors.lastname: Villalobo
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002147:Calmodulin / Q000378:metabolism / Q000494:pharmacology; D002154:Calpain / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D002846:Chromatography, Affinity; D017630:Connexins / Q000378:metabolism*; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D066246:ErbB Receptors / Q000378:metabolism*; D017629:Gap Junctions / Q000187:drug effects / Q000378:metabolism*; D007700:Kinetics; D008099:Liver; D008297:Male; D051379:Mice; D019606:Phosphoamino Acids / Q000032:analysis; D010766:Phosphorylation / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D014443:Tyrosine / Q000378:metabolism; D000097002:Gap Junction beta-1 Protein
chemical_list: D002147:Calmodulin; D002154:Calpain; D017630:Connexins; D004815:Epidermal Growth Factor; D066246:ErbB Receptors; D019606:Phosphoamino Acids; D014443:Tyrosine; D000097002:Gap Junction beta-1 Protein