RGD Reference Report - Phenylephrine promotes phosphorylation of Bad in cardiac myocytes through the extracellular signal-regulated kinases 1/2 and protein kinase A. - Rat Genome Database

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Phenylephrine promotes phosphorylation of Bad in cardiac myocytes through the extracellular signal-regulated kinases 1/2 and protein kinase A.

Authors: Valks, DM  Cook, SA  Pham, FH  Morrison, PR  Clerk, A  Sugden, PH 
Citation: Valks DM, etal., J Mol Cell Cardiol. 2002 Jul;34(7):749-63.
RGD ID: 2292701
Pubmed: PMID:12099715   (View Abstract at PubMed)

Studies in non-cardiomyocytic cells have shown that phosphorylation of the Bcl-2 family protein Bad on Ser-112, Ser-136 and Ser-155 decreases its pro-apoptotic activity. Both phenylephrine (100 microM) and the cell membrane-permeating cAMP analog, 8-(4-chlorophenylthio)-cAMP (100 microM), protected against 2-deoxy-D-glucose-induced apoptosis in neonatal rat cardiac myocytes as assessed by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL). In cardiac myocytes, phenylephrine primarily stimulates the alpha-adrenoceptor, but, at high concentrations (100 microM), it also increases the activity of the cAMP-dependent protein kinase, protein kinase A (PKA) through the beta-adrenoceptor. Phenylephrine (100 microM) promoted rapid phosphorylation of Bad(Ser-112) and Bad(Ser-155), though we were unable to detect phosphorylation of Bad(Ser-136). Phosphorylation of Bad(Ser-112) was antagonized by either prazosin or propranolol, indicating that this phosphorylation required stimulation of both alpha(1)- and beta-adrenoceptors. Phosphorylation of Bad(Ser-155) was antagonized only by propranolol and was thus mediated through the beta-adrenoceptor. Inhibitor studies and partial purification of candidate kinases by fast protein liquid chromatography showed that the p90 ribosomal S6 kinases, p90RSK2/3 [which are activated by the extracellular signal-regulated kinases 1 and 2 (ERK1/2)] directly phosphorylated Bad(Ser-112), whereas the PKA catalytic subunit directly phosphorylated Bad(Ser-155). However, efficient phosphorylation of Bad(Ser-112) also required PKA activity. These data suggest that, although p90RSK2/3 phosphorylate Bad(Ser-112) directly, phosphorylation of this site is enhanced by phosphorylation of Bad(Ser-155). These phosphorylations potentially diminish the pro-apoptotic activity of Bad and contribute to the cytoprotective effects of phenylephrine and 8-(4-chlorophenylthio)-cAMP.

Gene Ontology Annotations    Click to see Annotation Detail View

Biological Process
TermQualifierEvidenceWithReferenceNotesSourceOriginal Reference(s)
response to xenobiotic stimulus  IEP 2292701 RGD 

Objects Annotated

Genes (Rattus norvegicus)
Bad  (BCL2-associated agonist of cell death)


Additional Information