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Lipid raft proteome reveals ATP synthase complex in the cell surface
Author(s) -
Bae TaeJung,
Kim MinSik,
Kim JunWoo,
Kim BongWoo,
Choo HyoJung,
Lee JoongWon,
Kim KiBum,
Lee Chang Seok,
Kim JiHyun,
Chang Sun Young,
Kang ChangYuil,
Lee SangWon,
Ko YoungGyu
Publication year - 2004
Publication title -
proteomics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.26
H-Index - 167
eISSN - 1615-9861
pISSN - 1615-9853
DOI - 10.1002/pmic.200400952
Subject(s) - lipid raft , raft , microbiology and biotechnology , membrane protein , biology , atp synthase , cell fractionation , biotinylation , biochemistry , mitochondrion , proteome , proteomics , inner mitochondrial membrane , chemistry , signal transduction , membrane , organic chemistry , gene , copolymer , enzyme , polymer
Since detergent‐resistant lipid rafts are involved in pathogen invasion, cholesterol homeostasis, angiogenesis, neurodegenerative diseases and signal transduction, protein identification in the rafts could provide important information to study their function. Here, we analyzed detergent‐resistant raft proteins isolated from rat liver by capillary liquid chromatography‐tandem mass spectrometry. Out of 196 proteins identified, 32% belonged to the raft or plasma membrane, 24% to mitochondrial, 20% to microsomal, 7% to miscellaneous, and 17% are unknown proteins. For example, membrane‐bound receptors, trimeric GTP‐binding proteins, ATP‐binding cassette transporters, and glycosylphosphatidylinositol‐anchored proteins were identified in this analysis. Unexpectedly, there were many mitochondrial proteins, raising a new issue for the presence of mitochondrial rafts or the localization of mitochondrial proteins into plasma membrane rafts. We confirmed that ATP synthase α and β were expressed on the surface of the plasma membrane in HepG2 hepatocytes by immunofluorescence, cell surface biotinylation, and cellular fractionation. They had two distinct biochemical properties, detergent insolubility and low density, suggesting that the ATP synthase complex might be located in plasma membrane rafts as well as in the mitochondria.