title: PKC-delta and CaMKII-delta 2 mediate ATP-dependent activation of ERK1/2 in vascular smooth muscle.
abstract: ATP, a purinergic receptor agonist, has been shown to be involved in vascular smooth muscle (VSM) cell DNA synthesis and cell proliferation during embryonic and postnatal development, after injury, and in atherosclerosis. One mechanism that ATP utilizes to regulate cellular function is through activation of ERK1/2. In the present study, we provide evidence that ATP-dependent activation of ERK1/2 in VSM cells utilizes specific isoforms of the multifunctional serine/threonine kinases, PKC, and Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) as intermediates. Selective inhibition of PKC-delta activity with rottlerin, or adenoviral overexpression of kinase-negative PKC-delta, attenuated the ATP- and phorbol 12,13-dibutyrate (PDBu)-stimulated ERK1/2 activation. Inhibition of PKC-alpha activity with Gö-6976, or adenoviral overexpression of kinase-negative PKC-alpha, was ineffective. Alternatively, treatment with KN-93, a selective inhibitor of CaMKII activation, or adenoviral overexpression of kinase-negative CaMKII-delta(2), inhibited ATP-dependent activation of ERK1/2 but had no effect on PDBu- or PDGF-stimulated ERK1/2. In addition, adenoviral overexpression of dominant-negative ras (Ad.HA-Ras(N17)) partially inhibited the ATP- and PDBu-induced activation of ERK1/2 and blocked ionomycin- and EGF-stimulated ERK1/2, and inhibition of tyrosine kinases with AG-1478, an EGFR inhibitor, or the src family kinase inhibitor PP2 attenuated ATP-stimulated ERK1/2 activation. Taken together, these data indicate that PKC-delta and CaMKII-delta(2) coordinately mediate ATP-dependent transactivation of EGF receptor, resulting in increased ERK1/2 activity in VSM cells.
authors.affiliation: Center for Cardiovascular Sciences, Albany Medical College, New York 12208, USA.
authors.forename: Roman
authors.initials: R
authors.lastname: Ginnan
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Pfleiderer
authors.forename: Kevin
authors.initials: K
authors.lastname: Pumiglia
authors.forename: Harold A
authors.initials: HA
authors.lastname: Singer
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D004791:Enzyme Inhibitors / Q000494:pharmacology; D066246:ErbB Receptors / Q000187:drug effects / Q000378:metabolism; D005822:Genetic Vectors; D006133:Growth Substances / Q000378:metabolism / Q000494:pharmacology; D007527:Isoenzymes / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000187:drug effects / Q000378:metabolism*; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000201:enzymology*; D009154:Mutation / Q000235:genetics; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000201:enzymology*; D011493:Protein Kinase C / Q000378:metabolism*; D051745:Protein Kinase C-delta; D051381:Rats; D017207:Rats, Sprague-Dawley; D019061:src-Family Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: D004791:Enzyme Inhibitors; D006133:Growth Substances; D007527:Isoenzymes; D000255:Adenosine Triphosphate; C497260:Prkcd protein, rat; D066246:ErbB Receptors; D019061:src-Family Kinases; D011493:Protein Kinase C; D051745:Protein Kinase C-delta; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases