Quantitative proteomic comparison of rat mitochondria from muscle, heart and liver.
Mol Cell Proteomics. 2006 Apr;5(4):608-19. Epub 2006 Jan 14.
Forner F, Foster LJ, Campanaro S, Valle G, Mann M.
Proteomics and Signal Transduction, Max-Planck Institute for Biochemistry, Martinsried 82152.
Mitochondria, through oxidative phosphorylation, are the primary source of energy production in all tissues under aerobic conditions. While critical to life, energy production is not the only function of mitochondria and the composition of this organelle is tailored to meet the specific needs of each cell type. As an organelle, the mitochondrion has been a popular subject for proteomic analysis but quantitative proteomic methods have yet to be applied to tease apart subtle differences among mitochondria from different tissues or muscle types. Here we use mass spectrometry-based quantitative proteomics to analyze mitochondrial proteins extracted from rat skeletal muscle, heart and liver tissues. Based on 689 proteins identified with high confidence, mitochondria from the different tissues are qualitatively quite similar. However, striking differences emerged from the quantitative comparison of protein abundance between the tissues. Furthermore, we have applied similar methods to analyze mitochondrial matrix and intermembrane space proteins extracted from the same mitochondrial source, providing evidences for the sub-mitochondrial localization of a number of proteins in skeletal muscle and liver. Several proteins not previously thought to reside in mitochondria were identified, and their presence in this organelle was confirmed by protein correlation profiling. Hierarchical clustering of microarray expression data provided further evidence that some of the novel mitochondrial candidates identified in the proteomics survey might be associated with mitochondria. These data reveal several important distinctions between mitochondrial and sub-mitochondrial proteomes from different tissue sources. Indeed, approximately one third of the proteins identified in the soluble fractions are associated predominatly to one of the three tissues, indicating a tissue-dependent regulation of mitochondrial proteins. Furthermore, a small percentage of the mitochondrial proteome is unique to each tissue.
http://www.mcponline.org/cgi/reprint/M500298-MCP200v1
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