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标题：Sphingolipids and cholesterol modulate membrane susceptibility to cytosolic phospholipase A2
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作者：Elsa Klapisz ; Joëlle Masliah ; Gilbert Béréziat 等
期刊名称：JLR Papers In Press
印刷版ISSN：0022-2275
电子版ISSN：1539-7262
出版年度：2000
卷号：41
期号：10
页码：1680-1688
语种：English
出版社：American Society for Biochemistry and Molecular Biology
摘要：Modulation of cytosolic phospholipase A₂ (cPLA₂) activity by sphingomyelin (SPH), ceramide (Cer), and cholesterol (Chol) was investigated in CHO-2B cells activated by the calcium ionophore A23187 and epinephrine. Chol depletion of CHO-2B cells by treatment with methyl-β-cyclodextrin (5 m m ) resulted in the inhibition of the release of arachidonic acid whereas the restoration of the level by Chol-loaded cyclodextrin relieved inhibition. Conversion of CHO-2B cellular SPH to Cer by Staphylococcus aureus sphingomyelinase enhanced endogenous cPLA₂ activation as well as uptake by cells of C2- and C6-ceramide analogs. These results were confirmed in vitro with purified human recombinant cPLA₂ acting on a model phospholipid substrate. The enzyme activity was inhibited by SPH but reactivated by Cer as well as by Chol added to glycerophospholipid liposomal substrates containing SPH. The results of this study, which combine in situ and in vitro experimental approaches, indicate that membrane microdomains enriched in SPH and Chol play a role in the modulation of the activity of cPLA₂ and in arachidonic acid-derived mediator production. —Klapisz, E., J. Masliah, G. Béréziat, C. Wolf, and K. S. Koumanov. Sphingolipids and cholesterol modulate membrane susceptibility to cytosolic phospholipase A₂. J. Lipid Res. 2000. 41: 1680–1688.
关键词：arachidonic acid ; ceramide ; CHO cells ; cholesterol ; phospholipase A₂ ; sphingomyelin