Extracellular ATP is generated by ATP synthase complex in adipocyte lipid rafts.
- Author:
Bong Woo KIM
1
;
Hyo Jung CHOO
;
Joong Won LEE
;
Ji Hyun KIM
;
Young Gyu KO
Author Information
1. Graduate School of Life Sciences and Biotechnology, Korea University, Seoul 136-701, Korea. ygko@korea.ac.kr
- Publication Type:Original Article ; Research Support, Non-U.S. Gov't
- Keywords:
adipocytes;
ATP synthase complex;
membrane microdomains;
mitochondria
- MeSH:
Adenosine Triphosphate/analysis/*biosynthesis;
Adipocytes/*enzymology/ultrastructure;
Animals;
Cell Differentiation/physiology;
Cell Membrane/chemistry;
Cells, Cultured;
Humans;
Membrane Microdomains/chemistry/*enzymology;
Mice;
Mitochondria/metabolism/ultrastructure;
Mitochondrial Proton-Translocating ATPases/analysis/*physiology;
Research Support, Non-U.S. Gov't
- From:Experimental & Molecular Medicine
2004;36(5):476-485
- CountryRepublic of Korea
- Language:English
-
Abstract:
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 micrometer) 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.
