title: Differential pathways of angiotensin II-induced extracellularly regulated kinase 1/2 phosphorylation in specific cell types: role of heparin-binding epidermal growth factor.
abstract: Stimulation of the angiotensin II (Ang II) type 1 receptor (AT1-R) causes phosphorylation of extracellularly regulated kinases 1 and 2 (ERK1/2) via epidermal growth factor receptor (EGF-R) transactivation-dependent or -independent pathways in Ang II target cells. Here we examined the mechanisms involved in agonist-induced EGF-R transactivation and subsequent ERK1/2 phosphorylation in clone 9 (C9) hepatocytes, which express endogenous AT1-R, and COS-7 and human embryonic kidney (HEK) 293 cells transfected with the AT1-R. Ang II-induced ERK1/2 activation was attenuated by inhibition of Src kinase and of matrix metalloproteinases (MMPs) in C9 and COS-7 cells, but not in HEK 293 cells. Agonist-mediated MMP activation in C9 cells led to shedding of heparin-binding EGF (HB-EGF) and stimulation of ERK1/2 phosphorylation. Blockade of HB-EGF action by neutralizing antibody or its selective inhibitor, CRM197, attenuated ERK1/2 activation by Ang II. Consistent with its agonist action, HB-EGF stimulation of these cells caused marked phosphorylation of the EGF-R and its adapter molecule, Shc, as well as ERK1/2 and its dependent protein, p90 ribosomal S6 kinase, in a manner similar to that elicited by Ang II or EGF. Although the Tyr319 residue of the AT1-R has been proposed to be an essential regulator of EGF-R transactivation, stimulation of wild-type and mutant (Y319F) AT1-R expressed in COS-7 cells caused EGF-R transactivation and subsequent ERK1/2 phosphorylation through release of HB-EGF in a Src-dependent manner. In contrast, the noninvolvement of MMPs in HEK 293 cells, which may reflect the absence of Src activation by Ang II, was associated with lack of transactivation of the EGF-R. These data demonstrate that the individual actions of Ang II on EGF-R transactivation in specific cell types are related to differential involvement of MMP-dependent HB-EGF release.
authors.affiliation: Endocrinology and Reproduction Research Branch, National Institute of Child Health and Human Development, Building 49, Room 6A36, National Institutes of Health, Bethesda, Maryland 20892-4510, USA.
authors.forename: Bukhtiar H
authors.initials: BH
authors.lastname: Shah
authors.forename: Akin
authors.initials: A
authors.lastname: Yesilkaya
authors.forename: J Alberto
authors.initials: JA
authors.lastname: Olivares-Reyes
authors.forename: Hung-Dar
authors.initials: HD
authors.lastname: Chen
authors.forename: László
authors.initials: L
authors.lastname: Hunyady
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Catt
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D000081247:CSK Tyrosine-Protein Kinase; D002460:Cell Line; D002522:Chlorocebus aethiops; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D066246:ErbB Receptors / Q000378:metabolism; D066257:Heparin-binding EGF-like Growth Factor; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D007700:Kinetics; D045726:Metalloproteases / Q000037:antagonists & inhibitors / Q000378:metabolism; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism*; D009928:Organ Specificity; D010766:Phosphorylation / Q000187:drug effects; D011493:Protein Kinase C / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D051381:Rats; D044140:Receptor, Angiotensin, Type 1; D055765:Shc Signaling Adaptor Proteins; D015398:Signal Transduction / Q000187:drug effects*; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D015533:Transcriptional Activation / Q000187:drug effects; D019061:src-Family Kinases
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C587883:HBEGF protein, human; C587885:Hbegf protein, rat; D066257:Heparin-binding EGF-like Growth Factor; D036341:Intercellular Signaling Peptides and Proteins; D044140:Receptor, Angiotensin, Type 1; C528024:SHC1 protein, human; D055765:Shc Signaling Adaptor Proteins; C528035:Shc1 protein, rat; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D000804:Angiotensin II; D004815:Epidermal Growth Factor; D066246:ErbB Receptors; D011505:Protein-Tyrosine Kinases; D000081247:CSK Tyrosine-Protein Kinase; D019061:src-Family Kinases; C000631346:CSK protein, human; D011493:Protein Kinase C; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D045726:Metalloproteases