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Inactivation of mitochondrial respiratory chain complex I leads mitochondrial nitric oxide synthase to become

Mordhwaj S Parihar1, Arti Parihar, Frederick A Villamena

  • 1Department of Surgery, Davis Heart and Lung Research Institute, and Institute of Mitochondrial Biology, The Ohio State University, Columbus, OH 43210, USA.

Biochemical and Biophysical Research Communications
|January 15, 2008
PubMed

Insights

Inactivating mitochondrial complex I causes mitochondrial nitric oxide synthase (mtNOS) to become pro-oxidative. This suggests mtNOS plays a key role in oxidative stress linked to complex I dysfunction.

Area of Science:

  • Mitochondrial biology
  • Biochemistry
  • Cellular oxidative stress

Background:

  • Mitochondrial nitric oxide synthase (mtNOS) was previously shown to couple with respiratory chain complex I.
  • The functional consequences of this interaction under conditions of complex I dysfunction were not fully understood.

Purpose of the Study:

  • To investigate the behavior of mtNOS when mitochondrial complex I is inactivated.
  • To determine the role of mtNOS in oxidative stress resulting from complex I inactivation.

Main Methods:

  • Mitochondrial complex I inactivation was induced.
  • The activity and oxidative state of mtNOS were assessed under these conditions.

Main Results:

  • Inactivation of complex I resulted in mtNOS adopting a pro-oxidative function.
  • This shift in mtNOS activity was observed in conjunction with complex I dysfunction.

Conclusions:

  • mtNOS activity is significantly altered by the functional state of mitochondrial complex I.
  • mtNOS is implicated as a critical factor contributing to oxidative stress when complex I is inactivated.

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