title: Functional significance of protein kinase A activation by endothelin-1 and ATP: negative regulation of SRF-dependent gene expression by PKA.
abstract: Endothelin-1 (ET1) and ATP stimulate contraction and hypertrophy of vascular smooth muscle cells (VSMC) by activating diverse signalling pathways. In this study, we show that in VSMC, ET1 and ATP stimulate transient and sustained activation of protein kinase A (PKA), respectively. Using a dominant negative PKA mutant (PKA-DN), we examined the functional significance of PKA activation in the signalling of ET1 and ATP. Overexpression of PKA-DN did not alter the ET1- or ATP-induced phosphorylation of the extracellular signal-regulated protein kinase, Erk2. ATP stimulated a profound, PKA-dependent activation of cAMP-response element (CRE), whereas the effect of ET1 was negligible. Both ET1 and ATP stimulated serum response factor (SRF)-dependent gene expression. Overexpression of PKA-DN potentiated the effects of ET1 and ATP on SRF activity, whereas stimulation of PKA by isoproterenol, forskolin or by overexpression of the PKA catalytic subunit decreased SRF activity. These data demonstrate that (i) PKA negatively regulates SRF activity and (ii) ET1 and ATP stimulate opposing pathways, whose balance determines the net activity of SRF.
authors.affiliation: Section of Pulmonary and Critical Care Medicine, Department of Medicine, The University of Chicago, 5841 S. Maryland Avenue, MC 6076, Chicago, IL 60637, USA.
authors.forename: Amanda
authors.initials: A
authors.lastname: Davis
authors.forename: Kyle
authors.initials: K
authors.lastname: Hogarth
authors.forename: Darren
authors.initials: D
authors.lastname: Fernandes
authors.forename: Julian
authors.initials: J
authors.lastname: Solway
authors.forename: Jiaxin
authors.initials: J
authors.lastname: Niu
authors.forename: Vladimir
authors.initials: V
authors.lastname: Kolenko
authors.forename: Darren
authors.initials: D
authors.lastname: Browning
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Miano
authors.forename: Sergei N
authors.initials: SN
authors.lastname: Orlov
authors.forename: Nickolai O
authors.initials: NO
authors.lastname: Dulin
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D002460:Cell Line; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism* / Q000502:physiology; D015536:Down-Regulation; D019332:Endothelin-1 / Q000494:pharmacology*; D004789:Enzyme Activation; D005786:Gene Expression Regulation; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism; D010766:Phosphorylation; D051381:Rats; D011921:Rats, Inbred WKY; D020218:Response Elements; D026362:Serum Response Factor / Q000378:metabolism*; D015533:Transcriptional Activation
chemical_list: D019332:Endothelin-1; D026362:Serum Response Factor; D000255:Adenosine Triphosphate; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D020928:Mitogen-Activated Protein Kinases