title: Epidermal-growth-factor receptor and metalloproteinases mediate thromboxane A2-dependent extracellular-signal-regulated kinase activation.
abstract: The signalling pathways that link G-protein-coupled receptors to mitogen-activated protein kinases involve receptor and non-receptor tyrosine kinases and protein kinase C (PKC). We explored the pathways that are implicated in the thromboxane (TX) A(2)-dependent activation of extracellular-signal-regulated protein kinase (ERK) and the role of the two TX receptor (TP) isoforms, TP alpha and TP beta. ERK activation by IBOP, a TX analogue, was dependent on epidermal-growth-factor receptor (EGFR) in TP alpha- or TP beta-transfected cells and in human aortic smooth muscle cells (hASMCs), since AG1478, a selective inhibitor of tyrosine phosphorylation of the EGFR, strongly blocked ERK and EGFR phosphorylation. In addition, EGFR transactivation leading to ERK activation involved matrix metalloproteinases (MMPs), since BB2516, an inhibitor of MMP, decreased ERK and EGFR phosphorylation in TP alpha- or TP beta-transfected cells. Moreover, we showed that both isoforms activate ERK phosphorylation in an Src-kinase-dependent manner, whereas PKC was mainly implicated in ERK activation and EGFR phosphorylation by TP beta. In hASMCs, we showed that ERK activation depended on both pertussis-sensitive and -insensitive G alpha-proteins. We demonstrated further that EGFRs, PKC, Src kinase and MMPs are involved in ERK activation by TX. The results of the present study highlight a role for MMPs and PKC in EGFR transactivation triggered by the TPs and demonstrate this mechanism for the first time in primary cells, i.e. hASMCs.
authors.affiliation: INSERM U348, Institut Fédératif 6-Circulation-Paris 7,8 rue Guy Patin, Hôpital Lariboisière, 75010 Paris Cedex, France.
authors.forename: Carole
authors.initials: C
authors.lastname: Gallet
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Blaie
authors.forename: Sylviane
authors.initials: S
authors.lastname: Lévy-Toledano
authors.forename: Aïda
authors.initials: A
authors.lastname: Habib
mesh_terms: D015153:Blotting, Western; D019086:Bridged Bicyclo Compounds, Heterocyclic; D002460:Cell Line; D004789:Enzyme Activation; D066246:ErbB Receptors / Q000378:metabolism*; D005231:Fatty Acids, Unsaturated; D005419:Flavonoids / Q000494:pharmacology; D006801:Humans; D006834:Hydrazines / Q000494:pharmacology; D008666:Metalloendopeptidases / Q000378:metabolism*; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism; D013928:Thromboxane A2 / Q000378:metabolism*
chemical_list: D019086:Bridged Bicyclo Compounds, Heterocyclic; D005231:Fatty Acids, Unsaturated; D005419:Flavonoids; D006834:Hydrazines; D013928:Thromboxane A2; C045749:SQ 29548; D066246:ErbB Receptors; D011493:Protein Kinase C; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D008666:Metalloendopeptidases; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one