The effect of α-adrenergic agents and protein kinase C activators on protein phosphorylation in isolated guinea pig hearts

I. Edes, L. Talosi, E. G. Kranias

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

The incorporation of [32P]Pi into sarcolemmal, sarcoplasmic reticular and myofibrillar proteins was studied in Langendorff-perfused guinea pig hearts treated with the α-agonist norepinephrine or with protein kinase C activators (phorbol 12-myristate 13-acetate (PMA) or 1,2-dioctanoylglycerol (D8G)). Norepinephrine was administered in the presence of propranolol and atropine, while the protein kinase C activators (PMA and D8G) were infused in the presence of propranolol, atropine and prazosin. Examination of 32P-incorporation into the various cardiac proteins revealed that there were no significant increases in the degree of phosphorylation of the: (1) 15 kDa sarcolemmal protein; (2) phospholamban in sarcoplasmic reticulum; and (3) troponin I and C protein in the myofibrils. In parallel control studies, stimulation of beating guinea pig hearts by isoproterenol was associated with a 4-5-fold increase in 32P-incorporation into phospholamban and troponin I and about a 2-fold increase in 32P-incorporation into C protein and the 15 kDA sarcolemmal protein. These findings indicate that the major cardiac regulatory phosphoproteins, which have been reported to serve as substrates for protein kinase C in vitro, are not phosphorylated by the same enzyme in perfused, beating guinea pig hearts.

Original languageEnglish
Pages (from-to)143-144
Number of pages2
JournalEuropean heart journal
Volume12
Issue numberSUPPL. F
Publication statusPublished - Dec 1 1991

Keywords

  • Adrenergic receptors
  • Protein kinase C
  • Protein phosphorylation

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

Fingerprint Dive into the research topics of 'The effect of α-adrenergic agents and protein kinase C activators on protein phosphorylation in isolated guinea pig hearts'. Together they form a unique fingerprint.

  • Cite this