title: Calcium-dependent epidermal growth factor receptor transactivation mediates the angiotensin II-induced mitogen-activated protein kinase activation in vascular smooth muscle cells.
abstract: We have recently reported that angiotensin II (Ang II)-induced mitogen-activated protein kinase (MAPK) activation is mainly mediated by Ca2+-dependent activation of a protein tyrosine kinase through Gq-coupled Ang II type 1 receptor in cultured rat vascular smooth muscle cells (VSMC). In the present study, we found Ang II rapidly induced the tyrosine phosphorylation of the epidermal growth factor (EGF) receptor and its association with Shc and Grb2. These reactions were inhibited by the EGF receptor kinase inhibitor, AG1478. The Ang II-induced phosphorylation of the EGF receptor was mimicked by a Ca2+ ionophore and completely inhibited by an intracellular Ca2+ chelator. Thus, AG1478 abolished the MAPK activation induced by Ang II, a Ca2+ ionophore as well as EGF but not by a phorbol ester or platelet-derived growth factor-BB in the VSMC. Moreover, Ang II induced association of EGF receptor with catalytically active c-Src. This reaction was not affected by AG1478. These data indicate that Ang II induces Ca2+-dependent transactivation of the EGF receptor which serves as a scaffold for pre-activated c-Src and for downstream adaptors, leading to MAPK activation in VSMC.
authors.affiliation: Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA.
authors.forename: S
authors.initials: S
authors.lastname: Eguchi
authors.forename: K
authors.initials: K
authors.lastname: Numaguchi
authors.forename: H
authors.initials: H
authors.lastname: Iwasaki
authors.forename: T
authors.initials: T
authors.lastname: Matsumoto
authors.forename: T
authors.initials: T
authors.lastname: Yamakawa
authors.forename: H
authors.initials: H
authors.lastname: Utsunomiya
authors.forename: E D
authors.initials: ED
authors.lastname: Motley
authors.forename: H
authors.initials: H
authors.lastname: Kawakatsu
authors.forename: K M
authors.initials: KM
authors.lastname: Owada
authors.forename: Y
authors.initials: Y
authors.lastname: Hirata
authors.forename: F
authors.initials: F
authors.lastname: Marumo
authors.forename: T
authors.initials: T
authors.lastname: Inagami
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D001013:Aorta, Thoracic / Q000166:cytology / Q000187:drug effects / Q000201:enzymology; D002118:Calcium / Q000378:metabolism*; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D002478:Cells, Cultured; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D066246:ErbB Receptors / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051380:GRB2 Adaptor Protein; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D009570:Nitriles / Q000494:pharmacology; D010766:Phosphorylation; D019000:Phosphotyrosine / Q000378:metabolism; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D017027:Protein Tyrosine Phosphatases / Q000037:antagonists & inhibitors; D011506:Proteins / Q000378:metabolism*; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000378:metabolism*; D011799:Quinazolines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D020032:Tyrphostins; D018909:src Homology Domains
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D004791:Enzyme Inhibitors; D051380:GRB2 Adaptor Protein; C495950:Grb2 protein, rat; D009570:Nitriles; D011506:Proteins; D011799:Quinazolines; D020032:Tyrphostins; D000804:Angiotensin II; C101044:RTKI cpd; D019000:Phosphotyrosine; D066246:ErbB Receptors; D016392:Proto-Oncogene Proteins pp60(c-src); D017871:Calcium-Calmodulin-Dependent Protein Kinases; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D017027:Protein Tyrosine Phosphatases; D002118:Calcium