Mitochondria do not contain lipid rafts, and lipid rafts do not contain mitochondrial proteins.
Lipid rafts are membrane microdomains involved in many cellular functions, including transduction of cellular signals and cell entry by pathogens. Lipid rafts can be enriched biochemically by extraction in a nonionic detergent at low temperature, followed by floatation on a sucrose density gradient. Previous proteomic studies of such detergent-resistant membranes (DRMs) are in disagreement about the presence of mitochondrial proteins in raft components. Here, we approach the status of mitochondrial proteins in DRM preparations by employing stable isotope labeling by amino acids in cell culture to evaluate the composition of differentially purified subcellular fractions as well as high-resolution linear density gradients. Our data demonstrate that F(1)/F(0) ATPase subunits, voltage-dependent anion selective channels, and other mitochondrial proteins are at best partially copurifying contaminants of raft preparations.
Zheng
Yu Zi
YZ
Department of Biochemistry and Molecular Biology, Centre for High-Throughput Biology, University of British Columbia, Vancouver, BC, Canada.
Berg
Kyra B
KB
Foster
Leonard J
LJ
D000818:Animals; D002460:Cell Line; D002784:Cholesterol / Q000378:metabolism; D003902:Detergents / Q000737:chemistry; D020869:Gene Expression Profiling; D006801:Humans; D007425:Intracellular Membranes / Q000737:chemistry*; D021962:Membrane Microdomains / Q000737:chemistry*; D051379:Mice; D008928:Mitochondria / Q000737:chemistry*; D024101:Mitochondrial Proteins / Q000032:analysis*; D020543:Proteome
D003902:Detergents; D024101:Mitochondrial Proteins; D020543:Proteome; D002784:Cholesterol