alpha(1B)- and alpha(1D)-Adrenergic receptors exhibit different requirements for agonist and mitogen-activated protein kinase activation to regulate growth responses in rat 1 fibroblasts.
We compared DNA replication, protein biosynthesis, and mitogen-activated protein kinase (MAPK) activity in Rat 1 fibroblasts stably expressing either the alpha(1B)-adrenergic receptor (AR) or alpha(1D)-AR subtypes. Activation of both the alpha(1B)-AR and alpha(1D)-AR inhibited DNA synthesis (as assessed by [(3)H]thymidine incorporation). In contrast, both receptors stimulated protein biosynthesis (as measured by [(35)S]methionine incorporation) and activated extracellular signal-regulated kinase (ERK)1/2. Importantly, these responses were agonist-dependent for the alpha(1B)-AR, but were agonist-independent for the alpha(1D)-AR. Agonist activation of the alpha(1B)-AR resulted in increased p38 kinase activity, but not c-Jun NH(2)-terminal kinase (JNK) activity, whereas the alpha(1D)-AR activated JNK but not p38 kinase. Unlike ERK1/2, JNK activity was increased by agonist treatment in the alpha(1D)-AR cells. An ERK1/2-pathway inhibitor PD98059 had no effect on phenylephrine-mediated inhibition of DNA synthesis in either cell line but blocked protein biosynthesis mediated by both receptors. The p38 kinase inhibitor SB203580 blocked alpha(1B)-AR effects on [(3)H]thymidine and [(35)S]methionine incorporation in alpha(1B)-AR-expressing cells, but had no effect on alpha(1D)-AR-mediated growth responses, consistent with the inability of the alpha(1D)-AR to activate p38 kinase. Therefore, alpha(1B)- and alpha(1D)-ARs mediated similar growth responses but differ with respect to the MAPK family member involved and the requirement for agonist.
Waldrop
Bruce A
BA
Division of Pharmaceutical Sciences, College of Medicine, University of Kentucky, Lexington, Kentucky 40536-0082, USA.
Mastalerz
Diana
D
Piascik
Michael T
MT
Post
Ginell R
GR
D058646:Adrenergic alpha-1 Receptor Agonists; D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000818:Animals; D015153:Blotting, Western; D002352:Carrier Proteins / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D004247:DNA / Q000096:biosynthesis; D004789:Enzyme Activation / Q000187:drug effects; D020536:Enzyme Activators / Q000494:pharmacology*; D005347:Fibroblasts / Q000187:drug effects; D007093:Imidazoles / Q000494:pharmacology; D007527:Isoenzymes / Q000378:metabolism; D048031:JNK Mitogen-Activated Protein Kinases; D048670:MAP Kinase Kinase 4; D008715:Methionine / Q000378:metabolism; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D011725:Pyridines / Q000494:pharmacology; D051381:Rats; D018340:Receptors, Adrenergic, alpha-1 / Q000187:drug effects*; D013936:Thymidine / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases
C547718:Adra1b protein, rat; C547721:Adra1d protein, rat; D058646:Adrenergic alpha-1 Receptor Agonists; D000316:Adrenergic alpha-Agonists; D002352:Carrier Proteins; D020536:Enzyme Activators; D007093:Imidazoles; D007527:Isoenzymes; D011725:Pyridines; D018340:Receptors, Adrenergic, alpha-1; D004247:DNA; D008715:Methionine; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D048670:MAP Kinase Kinase 4; D020929:Mitogen-Activated Protein Kinase Kinases; C093642:SB 203580; D013936:Thymidine