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Pull-down of Calmodulin-binding Proteins
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Pull-down of Calmodulin-binding Proteins

Published on: January 23, 2012

Nitric oxide-mediated modulation of calcium/calmodulin-dependent protein kinase II

Tao Song1, Naoya Hatano, Toshie Kambe

  • 1Department of Pharmacology, Showa Pharmaceutical University, Machida, Tokyo 194-8543, Japan.

The Biochemical Journal
|February 15, 2008
PubMed

Insights

Nitric oxide (NO) inhibits Ca(2+)/CaM-dependent protein kinase II (CaMKII) activity through S-nitrosylation at Cys(6). This mechanism, observed in rat pituitary and hippocampal cells, may play a role in NO-induced neurotoxicity.

Area of Science:

  • Neuroscience
  • Molecular Biology
  • Biochemistry

Background:

  • Calcium/calmodulin-dependent protein kinase II (CaMKII) is a crucial enzyme in neuronal signaling.
  • Nitric oxide (NO) is a signaling molecule implicated in various physiological and pathological processes, including neurotoxicity.
  • The interaction between NO and CaMKII activity is not fully understood.

Purpose of the Study:

  • To elucidate the mechanisms by which NO inhibits CaMKII activity.
  • To investigate the role of S-nitrosylation in NO-mediated CaMKII regulation.
  • To determine the potential contribution of this mechanism to NO-induced neurotoxicity.

Main Methods:

  • Experiments were conducted using rat pituitary GH3 cells and rat hippocampal slices.
  • Techniques included enzyme activity assays, Western blotting, site-directed mutagenesis (C6A CaMKII), mass spectrometry (MS), and treatment with NO donors and inhibitors.
  • Stimulation involved thyrotrophin-releasing hormone (TRH), calcium ionophore A23187, and glutamate.

Main Results:

  • NO donors and neuronal NO synthase (nNOS) inhibited CaMKII activity in vitro, with inhibition reversed by reducing agents.
  • CaMKII S-nitrosylation at Cys(6) was identified as the mechanism of inhibition, demonstrated by mutagenesis studies and MS.
  • Glutamate stimulation increased CaMKII S-nitrosylation in hippocampal slices, an effect blocked by nNOS inhibition.

Conclusions:

  • NO inhibits CaMKII activity via S-nitrosylation of cysteine 6.
  • This NO-mediated inactivation of CaMKII is a key molecular event.
  • CaMKII S-nitrosylation may contribute to NO-induced neurotoxicity in the brain.

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