Extracellular ATP is generated by ATP synthase complex in adipocyte lipid rafts
Extracellular ATP is generated by ATP synthase complex in adipocyte lipid rafts
复制标题
DOI：
10.1038/emm.2004.60
复制
发表时间：
2004-10-31
影响因子：
12.8
通讯作者：
Ko, YG
中科院分区：
文献类型：
--
作者：
Kim, BW;Choo, HJ;Ko, YG
已知线粒体生物合成伴随脂肪生成，以补充脂肪生成所需的ATP和乙酰辅酶A。在这里，我们证明了线粒体蛋白，如ATP合成酶α和β，细胞色素c在3 T3-L1分化成脂肪细胞的过程中高度表达。电子显微镜下完全分化的脂肪细胞线粒体明显增加。通过免疫荧光、细胞分级分离和表面生物素化的分析表明，不仅在线粒体中，而且在脂肪细胞的细胞表面（特别是脂筏）上发现ATP合酶复合物的水平升高。在脂肪细胞培养基中加入的ADP和Pi的ATP合成速率高（超过30 μ M），表明表面ATP合酶复合物参与了细胞外ATP合成。此外，这种ATP合成显着抑制寡霉素，ATP合成酶抑制剂，和羰基氰间氯苯腙（CCCP），ATP合成酶解偶联剂的存在下。细胞外ATP合成在酸性介质中减少而在碱性介质中不减少进一步表明表面ATP合酶也可能受到通过质膜的质子梯度的调节。
Mitochondrial biogenesis is known to accompany adipogenesis to complement ATP and acetyl-CoA required for lipogenesis. Here, we demonstrated that mitochondrial proteins such as ATP synthase alpha and beta, and cytochrome c were highly expressed during the 3T3-L1 differentiation into adipocytes. Fully-differentiated adipocytes showed a significant increase of mitochondria under electron microscopy. Analysis by immunofluorescence, cellular fractionation, and surface biotinylation demonstrated the elevated levels of ATP synthase complex found not only in the mitochondria but also on the cell surface (particularly lipid rafts) of adipocytes. High rate of ATP (more than 30 muM) synthesis from the added ADP and Pi in the adipocyte media suggests the involvement of the surface ATP synthase complex for the exracellular ATP synthesis. In addition, this ATP synthesis was significantly inhibited in the presence of oligomycin, an ATP synthase inhibitor, and carbonyl cyanide m-chlorophenylhydrazone (CCCP), an ATP synthase uncoupler. Decrease of extracellular ATP synthesis in acidic but not in basic media further indicates that the surface ATP synthase may also be regulated by proton gradient through the plasma membrane.