Age-associated oxidative modifications of mitochondrial α-subunit of F1 ATP synthase from mouse skeletal muscles

Abstract

The objective of this study was to investigate the pattern of age-associated oxidative post-translational modifications in the skeletal muscles of a mammalian species and to address whether the modifications result in the loss of function of the oxidatively modified protein(s). Accordingly, proteins in the mitochondrial matrix of the hind limb of C57BL/6Nnia mice were examined for modifications by carbonylation—an established marker of oxidative post-translational modifications—by Western blotting using anti-2,4-dinitrophenyl antibodies and tritiated sodium borohydride methods. An age-associated increase in carbonylation of mitochondrial matrix proteins was observed, but not all proteins were equally susceptible. A 55 kDa protein, identified as the α-subunit of the F1 complex of ATP synthase (ATP phosphohydrolase [H⁺-transporting]), had approximately 17% and 27% higher levels of protein carbonyls in adult and old animals, respectively, in comparison to the young controls as estimated using tritiated sodium borohydride. In addition, an age-associated decline in its activity was observed, with approximately 9% and 28% decrease in the activity in the adult and old animals, respectively, in comparison to young controls. It may be concluded that such oxidative post-translational modifications and the resultant attenuation of the protein activity may contribute to the age-related energy loss and muscular degeneracy.

Keywords::

• skeletal muscle
• carbonylation
• ATPase
• aging
• mitochondrial matrix
• oxidative post-translational modifications

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Acknowledgement

The authors would like to thank Prof Rajindar S. Sohal, Timothy M. Chan Professor, Department of Pharmacology and Pharmaceutical Sciences, University of Southern California, Los Angeles, CA 90089-9121, U.S.A. for laboratory facilities and funds during the course of this work; Dr. Robin J. Mockett, Department of Biomedical Sciences, University of South Alabama for critical reading of the manuscript; and Dr Surjya K Saikia, Department of Zoology and Dr Samiran Saha, Department of Biotechnology, Visva-Bharati University for help with statistical analysis and Photoshop software, respectively. The authors, N. Das and C.K. Jana, acknowledge Visva-Bharati University and Panchmura Mahavidyalaya, respectively, for necessary facilities.

Declaration of interest

The authors report no declarations of interest. The authors alone are responsible for the content and writing of the paper.