title: Critical role of calcium- dependent epidermal growth factor receptor transactivation in PC12 cell membrane depolarization and bradykinin signaling.
abstract: PC12 cells respond to a variety of external stimuli such as growth factors, neurotransmitters, and membrane depolarization by activating the Ras/mitogen-activated protein kinase pathway. Here we demonstrate that both depolarization-induced calcium influx and treatment with bradykinin stimulate tyrosine phosphorylation of the epidermal growth factor receptor (EGFR). Using a tetracycline-controlled expression system in conjunction with a dominant-negative EGFR mutant, we demonstrate that depolarization and bradykinin triggered signals involve EGFR function upstream of SHC and MAP kinase. Furthermore, bradykinin-stimulated EGFR transactivation is critically dependent on the presence of extracellular calcium, and when triggered by ionophore treatment, calcium influx is already sufficient to induce EGFR tyrosine phosphorylation. Taken together, our results establish calcium-dependent EGFR transactivation as a signaling mechanism mediating activation of the Ras/mitogen-activated protein kinase pathway in neuronal cell types.
authors.affiliation: Department of Molecular Biology, Max-Planck-Institut für Biochemie, Am Klopferspitz 18A, 82152 Martinsried, Germany.
authors.forename: E
authors.initials: E
authors.lastname: Zwick
authors.forename: H
authors.initials: H
authors.lastname: Daub
authors.forename: N
authors.initials: N
authors.lastname: Aoki
authors.forename: Y
authors.initials: Y
authors.lastname: Yamaguchi-Aoki
authors.forename: I
authors.initials: I
authors.lastname: Tinhofer
authors.forename: K
authors.initials: K
authors.lastname: Maly
authors.forename: A
authors.initials: A
authors.lastname: Ullrich
mesh_terms: D000818:Animals; D001920:Bradykinin / Q000494:pharmacology*; D002118:Calcium / Q000494:pharmacology*; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D002462:Cell Membrane / Q000187:drug effects / Q000502:physiology; D003587:Cytomegalovirus / Q000235:genetics; D004789:Enzyme Activation; D004815:Epidermal Growth Factor / Q000494:pharmacology; D066246:ErbB Receptors / Q000096:biosynthesis / Q000502:physiology*; D006801:Humans; D007476:Ionophores / Q000494:pharmacology; D008564:Membrane Potentials; D009414:Nerve Growth Factors / Q000494:pharmacology; D009474:Neurons / Q000502:physiology; D016716:PC12 Cells; D019000:Phosphotyrosine / Q000378:metabolism; D011401:Promoter Regions, Genetic; D051381:Rats; D015398:Signal Transduction; D013752:Tetracycline / Q000494:pharmacology; D015533:Transcriptional Activation / Q000187:drug effects*
chemical_list: D007476:Ionophores; D009414:Nerve Growth Factors; D019000:Phosphotyrosine; D004815:Epidermal Growth Factor; D066246:ErbB Receptors; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D013752:Tetracycline; D001920:Bradykinin; D002118:Calcium