Cell Metabolism Resource Proteome Differences between Brown and White Fat Mitochondria Reveal Specialized Metabolic Functions Francesca Forner,1,3 Chanchal Kumar,1,3,4 Christian A. Luber,1 Tobias Fromme,2 Martin Klingenspor,2 and Matthias Mann1,* 1Department of Proteomics and Signal Transduction, Max Planck Institute for Biochemistry, 82152 Martinsried, Germany 2Molecular Nutritional Medicine, ZIEL Research Center for Nutrition and Food Sciences, Technische Universita¨ tMu¨ nchen, Am Forum 5, 85350 Freising, Germany 3These authors contributed equally to this work 4Present address: Lilly Singapore Centre for Drug Discovery, 8A Biomedical Grove #02-05, Immunos, Biopolis 138648, Singapore *Correspondence:
[email protected] DOI 10.1016/j.cmet.2009.08.014 SUMMARY 2009). UCP1 ablation induces obesity in mice kept at thermo- neutrality (Feldmann et al., 2009). Mitochondria are functionally specialized in different White adipocytes are the major cellular components of tissues, and a detailed understanding of this special- visceral and subcutaneous WAT depots in humans (Cinti, ization is important to elucidate mitochondrial 2005). However, in addition to being a fat reservoir, WAT is involvement in normal physiology and disease. In also an active endocrine organ that produces and secretes adaptive thermogenesis, brown fat converts mito- many signaling molecules, termed adipokines, which are chondrial energy to heat, whereas tissue-specific involved in the regulation of food intake and energy homeostasis, and in the inflammatory states associated with metabolic disor- functions of mitochondria in white fat are less char- ders (Rosen and Spiegelman, 2006; Waki and Tontonoz, 2007). acterized. Here we apply high-resolution quantitative Thus WAT is involved in more diverse physiological processes mass spectrometry to directly and accurately com- than previously recognized.