Bidirectional transbilayer movement of phospholipid analogs in human red blood cells. Evidence for an ATP-dependent and protein-mediated process.
Bidirectional transbilayer movement of phospholipid analogs in human red blood cells. Evidence for an ATP-dependent and protein-mediated process.
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DOI：
10.1016/s0021-9258(18)41791-7
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发表时间：
1992-09
期刊：
影响因子：
--
通讯作者：
J. Connor;C. Pak;R. Zwaal;A. Schroit
中科院分区：
文献类型：
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作者：
J. Connor;C. Pak;R. Zwaal;A. Schroit
本文研究了荧光和同位素标记的磷脂酰丝氨酸（PS）、磷脂酰乙醇胺（PE）和磷脂酰胆碱（PC）类似物从人红细胞（RBC）的外叶到内叶（flip）和从内叶到外叶（flop）的跨双层运动。1-油酰基-2-（N-4-硝基苯并-2-氧杂-1，3-重氮-氨基己酰基）-（C6-NBD-），1-油酰基-2-（N-（3-（3-[125 I]碘-4-羟基苯基）丙酰基）氨基己酰基）-（C6- 125 I-N3-）或1-油酰基-2-（N-（3-[125 I]碘-4-叠氮基-苯基）丙酰基）氨基己酰基-（C6- 125 I-N3-）类似物。与此相反，所有类似物的PS和PE类似物含有氨基十二烷酸（C12脂质）迅速运输到细胞的内小叶。125 I-N3脂质交联膜蛋白的分析显示，标记的32-kDa的Rh多肽，这是依赖于脂质的能力被运送到内小叶，但独立的脂质种类。为了研究脂质是否也可以从内瓣叶转运到外瓣叶，监测仅存在于内瓣叶中的脂质探针在外瓣叶中的外观。在0 ℃下不能检测到脂质运动。然而，在37 ℃时，大约70%的PC、40%的PE和15%的PS重新分布到细胞外小叶，从而获得它们的正常不对称分布。在牛血清白蛋白存在下连续孵育以独立于脂质种类的方式耗尽类似物的细胞（t1/2约1.5 h）。与氨基磷脂的内向运动相似，PC、PE和PS的外向运动是ATP依赖性的，并且可以通过膜巯基的氧化和组氨酸试剂溴苯甲酰甲基溴来阻断。证据表明，向外运动的脂质是一个内在的属性无关的补偿机制，由于脂质分布的不平衡的细胞。
The transbilayer movement of fluorescent and isotopically labeled analogs of phosphatidylserine (PS), phosphatidylethanolamine (PE), and phosphatidylcholine (PC) from the outer to the inner leaflet (flip) and from the inner to the outer leaflet (flop) of human red blood cells (RBC) was examined. The inward movement of 1-oleoyl-2-(N-4-nitrobenzo-2-oxa-1,3-diazole-aminocaproyl)- (C6-NBD-), 1-oleoyl-2-(N-(3-(3-[125I]iodo-4-hydroxyphenyl)propionyl)aminocaproyl)- (C6-125I-), or 1-oleoyl-2-(N-(3-3-[125I]iodo-4-azido-phenyl)propionyl)aminocaproyl- (C6-125I-N3-) analogs of PC and PE were relatively slow. In contrast, all analogs of PS and PE analogs containing aminododecanoic acid (C12 lipids) were rapidly transported to the cell's inner leaflet. Analysis of 125I-N3 lipids cross-linked to membrane proteins revealed labeling of 32-kDa Rh polypeptides that was dependent on the lipid's capacity to be transported to the inner leaflet but was independent of lipid species. To investigate whether lipids could also be transported from the inner to the outer leaflet, lipid probes residing exclusively in the inner leaflet were monitored for their appearance in the outer leaflet. Lipid movement could not be detected at 0 degrees C. At 37 degrees C, however, approximately 70% of the PC, 40% of the PE, and 15% of the PS redistributed to the cells outer leaflet, thereby attaining their normal asymmetric distribution. Continuous incubation in the presence of bovine serum albumin depleted the cells of the analogs (t1/2 approximately 1.5 h) in a manner that was independent of lipid species. Similar to the inward movement of aminophospholipids, the outward movement of PC, PE, and PS was ATP-dependent and could be blocked by oxidation of membrane sulfhydryls and by the histidine reagent bromophenacyl bromide. Evidence is presented which suggests that the outward movement of lipids is an intrinsic property of the cells unrelated to compensatory mechanisms due to an imbalance in lipid distribution.