Abnormal transbilayer mobility of phosphatidylcholine in hereditary pyropoikilocytosis reflects the increased heat sensitivity of the membrane skeleton.
Abnormal transbilayer mobility of phosphatidylcholine in hereditary pyropoikilocytosis reflects the increased heat sensitivity of the membrane skeleton.
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遗传性焦磷酸细胞增多症中磷脂酰胆碱的异常跨双层流动性反映了膜骨架的热敏感性增加。
DOI：
10.1016/0005-2736(85)90296-2
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发表时间：
1985
期刊：
影响因子：
--
通讯作者：
Roelofsen,B
中科院分区：
文献类型：
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作者：
Franck,PF;OpdenKamp,JA;Lubin,B;Berendsen,W;Joosten,P;Briët,E;vanDeenen,LL;Roelofsen,B
我们确定遗传性焦斑细胞增多症（HPP）的膜缺陷是否与脂双层的热诱导变化有关，其稳定性通过两个小叶上的磷脂酰胆碱（PC）的移位率来探测。使用PC特异性磷脂交换蛋白将[14 C]PC掺入完整红细胞脂质双层的外叶中。通过测量其对外源性磷脂酶A2的可及性的时间依赖性变化来确定该PC的跨双层平衡。与正常红细胞相比，37°C下HPP细胞中PC的跨双层平衡速率增加（速率常数分别为0.07 ± 0.02和0.03 ± 0.01 h−1）。在44°C孵育的HPP细胞中，PC跨双层平衡进一步显著增加（速率常数为0.15 ± 0.02 h-1）。当在46°C下孵育时，在正常红细胞中也观察到PC跨双层运动的类似显著加速（速率常数为0.13 ± 0.03 h−1）。尽管增强transbilayer移动性的PC在HPP细胞相比，正常红细胞，没有重大的改变，可以观察到的不对称分布时，用磷脂酶A2探测。由于PC和细胞形态的transbilayer迁移率的变化发生在HPP细胞在较低的温度比在正常红细胞，它可以得出结论，增强的热敏感性血影蛋白是负责这些变化的主要因素。因此，我们的研究结果支持这样的观点，即骨架网络的结构完整性是必不可少的红细胞膜的脂质双层的稳定。
We determined whether the membrane defect in hereditary pyropoikilocytosis (HPP) is associated with thermally induced changes in the lipid bilayer, the stability of which was probed by the rate of translocation of phosphatidylcholine (PC) over the two leaflets. [14C]PC was incorporated into the outer leaflet of the lipid bilayer of the intact erythrocytes using a PC-specific phospholipid exchange protein. The transbilayer equilibration of this PC was determined by measuring the time-dependent changes in its accessibility to exogenous phospholipase A2. The rate of transbilayer equilibration of PC was increased in HPP cells at 37°C when compared to normal erythrocytes (rate constants, 0.07 ± 0.02 and 0.03 ± 0.01 h−1, respectively). A further dramatic increase in PC transbilayer equilibration was noted in HPP cells incubated at 44°C (rate constant, 0.15 ± 0.02 h−1). A similar marked acceleration in transbilayer movement of PC was also seen in normal erythrocytes when incubated at 46°C (rate constant, 0.13 ± 0.03 h−1). Despite the enhanced transbilayer mobility of PC in HPP cells when compared to normal erythrocytes, no major alteration in the asymmetric distribution could be observed when probed with phospholipase A2. Since changes in transbilayer mobility of PC and cell morphology occur in HPP cells at lower temperature than in normal red cells, it may be concluded that the enhanced themal sensitivity of spectrin is the major factor responsible for these changes. Our results therefore support the view that the structural integrity of the skeletal network is essential for stabilization of the lipid bilayer of the red cell membrane.