en
Scientific article
English

Role of protein phosphatase 2A in the regulation of mitogen-activated protein kinase activity in ventricular cardiomyocytes

Published inBiochemical and biophysical research communications, vol. 221, no. 3, p. 539-547
Publication date1996
Abstract

Incubation of cultured, neonatal rat ventricular cardiomyocytes with 100 nM phorbol 12-myristate-13-acetate (PMA) induced a transient suppression of PP2A activity at 5 min, an effect that was reversed after 15 min of exposure to PMA. This inactivation was correlated with a transient increase in the phosphorylation level of the catalytic subunit of PP2A (193 +/- 38% of control levels at 5 min). Simultaneously to the transient inactivation of PP2A, we observed a rapid and reversible phosphorylation of 42-kDa MAP kinase (474 +/- 65% of control levels at 5 min, and 316 +/- 44% at 15 min) in cardiomyocytes treated with PMA. This transient phosphorylation was accompanied by a transient increase in cytosolic MAP kinase activity (209 +/- 17% of control values at 5 min and 125 +/- 7% at 15 min). Okadaic acid (1 microM ) completely blocked the decrease in the phosphorylation level and activity of MAP kinase occurring after 5 min of exposure to PMA. These data demonstrate that PP2A inactivation and MAP kinase activation are very strongly correlated in cardiomyocytes, indicating that PP2A plays a negative modulatory role in the regulation of MAP kinase activity.

Keywords
  • Animals
  • Calcium-Calmodulin-Dependent Protein Kinases/metabolism
  • Cells, Cultured
  • Enzyme Activation
  • Ethers, Cyclic/pharmacology
  • Heart Ventricles/cytology/enzymology
  • Mitogen-Activated Protein Kinase 1
  • Mitogen-Activated Protein Kinase 3
  • Mitogen-Activated Protein Kinases
  • Okadaic Acid
  • Phosphoprotein Phosphatases/antagonists & inhibitors/metabolism
  • Phosphorylation
  • Protein Kinase C/metabolism
  • Protein Phosphatase 2
  • Protein-Tyrosine Kinases/metabolism
  • Rats
  • Rats, Wistar
  • Tetradecanoylphorbol Acetate/pharmacology
Citation (ISO format)
BRACONI QUINTAJE, Silvia et al. Role of protein phosphatase 2A in the regulation of mitogen-activated protein kinase activity in ventricular cardiomyocytes. In: Biochemical and biophysical research communications, 1996, vol. 221, n° 3, p. 539–547. doi: 10.1006/bbrc.1996.0632
Main files (1)
Article (Accepted version)
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Identifiers
ISSN of the journal0006-291X
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