An εPKC-selective inhibitor attenuates back phosphorylation of a low molecular weight protein in cardiac myocytes

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

We have studied εPKC-mediated phosphorylation events in neonatal cardiac myocytes using back phosphorylation. 3 nM 4-β 12-myristate-13-acetate (PMA)-intact cell treatment preferentially activates εPKC in these cells (Circ. Res. 76 (1995) 654) and caused decreased 32P incorporation (back phosphorylation) into an ∼18-kDa protein. This response required physiological levels of free Mg2+ and short (3-5 min) incubation periods in back phosphorylation assays. Introduction of a selective εPKC translocation inhibitor (εV1) into these cells attenuated the 3 nM PMA-induced back phosphorylation response while translocation inhibitors to the classical PKC or δPKC isozymes were without effect. Pretreatment of our cells with endothelin-1 (ET1) had similar effects to 3 nM PMA albeit the magnitude of the ET1 back phosphorylation response was about one-half that of 3 nM PMA. Our results suggest that εPKC phosphorylates an ∼18-kDa protein found in the particulate cell fraction of neonatal cardiac myocytes. εPKC modulates diverse cardiac responses including contraction, ion channel functions, hypertrophy, and ischemic preconditioning. Characterization of εPKC-selective phosphotransferase events may reveal novel regulatory mechanisms for this enzyme in neonatal cardiac myocytes.

Original languageEnglish (US)
Pages (from-to)123-130
Number of pages8
JournalCellular Signalling
Volume15
Issue number1
DOIs
StatePublished - Jan 1 2003

Fingerprint

Cardiac Myocytes
Molecular Weight
Phosphorylation
Proteins
Endothelin-1
Ischemic Preconditioning
Myristic Acid
Ion Channels
Hypertrophy
Isoenzymes
Acetates
Phosphotransferases
Enzymes

Keywords

  • Back phosphorylation
  • Cardiac myocyte
  • Magnesium
  • PKC isozymes
  • Phorbol
  • Translocation inhibitors

ASJC Scopus subject areas

  • Cell Biology

Cite this

An εPKC-selective inhibitor attenuates back phosphorylation of a low molecular weight protein in cardiac myocytes. / Johnson, John A.

In: Cellular Signalling, Vol. 15, No. 1, 01.01.2003, p. 123-130.

Research output: Contribution to journalArticle

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