Impact of actin glutathionylation on the actomyosin-S1 ATPase

Gresin O. Pizarro, Ozgur Ogut

Research output: Contribution to journalArticle

19 Scopus citations

Abstract

Glutathionylation of intracellular proteins is an established physiological regulator of protein function. In multiple models, including ischemia-reperfusion of the heart, increased oxidative stress results in the glutathionylation of sarcomeric actin. We hypothesized that actin glutathionylation may play a role in the multifactorial change in cardiac muscle contractility observed during this pathophysiological state. Therefore, the functional impact of glutathionylated actin on the interaction with myosin-S1 was examined. Substituting glutathionylated F-actin for unmodified F-actin reduced the maximum actomyosin-S1 ATPase, and this was accompanied by an increase in the activation energy of the steady state ATPase. Measurement of steady state binding did not suggest a large impact of actin glutathionylation on the binding to myosin-S1. However, transient binding and dissociation kinetics determined by stopped-flow methods demonstrated that although actin glutathionylation did not significantly alter the rate constant of myosin-S1 binding, there was a significant decrease in the rate of ATP-induced myosin-S1 detachment in the presence of ADP. These results suggest that actin glutathionylation may play a limited but defined role in the alteration of contractility following oxidative stress to the myocardium, particularly through a decrease in the actomyosin ATPase activity.

Original languageEnglish (US)
Pages (from-to)7533-7538
Number of pages6
JournalBiochemistry
Volume48
Issue number31
DOIs
StatePublished - Aug 11 2009

ASJC Scopus subject areas

  • Biochemistry

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