Cholesterol affects spectrin-phospholipid interactions in a manner different from changes resulting from alterations in membrane fluidity due to fatty acyl chain composition
Cholesterol affects spectrin-phospholipid interactions in a manner different from changes resulting from alterations in membrane fluidity due to fatty acyl chain composition
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DOI：
10.1016/j.bbamem.2005.11.009
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发表时间：
2006-01-01
影响因子：
3.4
通讯作者：
Sikorski, AF
中科院分区：
文献类型：
--
作者：
Diakowski, W;Ozimek, L;Sikorski, AF
我们先前表明，红细胞和脑血影蛋白结合磷脂囊泡和单层制备的磷脂酰乙醇胺和磷脂酰丝氨酸及其混合物与磷脂酰胆碱（审查：A.F.西科尔斯基，B。Hanus-Lorenz，A. Jezierski，A. R.张文，膜骨架蛋白与膜脂结构域的相互作用，生物化学学报。波兰人47（2000）565）。在这里，我们展示了磷脂单层流动性的变化如何影响血影蛋白-磷脂相互作用。在PE/PC单层中存在高达10%-20%的胆固醇有利于两种类型的血影蛋白渗透单层。对于由PI/PC和胆固醇的混合物构建的单层，血影蛋白的作用的特征在于存在两个最大值（在5%和30%胆固醇）的红细胞血影蛋白的表面压力，和一个单一的最大值（在20%胆固醇）的脑血影蛋白。结合试验结果表明，一个小的，但很容易检测到的减少红细胞血影蛋白的脂肪-脂质体制备的PE/PC混合物含有胆固醇的亲和力，最大结合能力（B-max）增加2至5倍，这取决于胆固醇含量。另一方面，用均质合成磷脂构建的单层的实验结果表明，随着用于制备单层的磷脂的脂肪酰基链长度的增加，Δ pi变化增加。这通过造粒实验的结果得到证实。将血影蛋白加入由DOPC、SM和胆固醇（1/1/1）构建的筏状单分子膜的亚相中，诱导表面压力增加。然而，Δ pi变化值远小于在天然PEW（6/4）单层的情况下观察到的值。从沉淀试验中也可以得出结论，从“筏状”脂质混合物制备的脂质体对血影蛋白的结合能力增加。总之，我们认为膜脂流动性对血影蛋白-磷脂相互作用的影响并不简单，而是取决于它是如何调节的，即，通过胆固醇含量或通过膜脂质的化学结构。(c)2005 Elsevier B. V.保留所有权利。
We previously showed that erythrocyte and brain spectrins bind phospholipid vesicles and monolayers prepared from phosphatidylethanolamine and phosphatidylserine and their mixtures with phosphatidylcholine (Review: A.F. Sikorski, B. Hanus-Lorenz, A. Jezierski, A. R. Dluzewski, Interaction of membrane skeletal proteins with membrane lipid domain, Acta Biochim. Polon. 47 (2000) 565). Here, we show how changes in the fluidity of the phospholipid monolayer affect spectrin-phospholipid interaction. The presence of up to 10%-20% cholesterol in the PE/PC monolayer facilitates the penetration of the monolayer by both types of spectrin. For monolayers constructed from mixtures of PI/PC and cholesterol, the effect of spectrins was characterised by the presence of two maxima (at 5 and 30% cholesterol) of surface pressure for erythroid spectrin, and a single maximum (at 20% cholesterol) for brain spectrin. The binding assay results indicated a small but easily detectable decrease in the affinity of erythrocyte spectrin for FAT-liposomes prepared from a PE/PC mixture containing cholesterol, and a 2- to 5-fold increase in maximal binding capacity (B-max) depending on the cholesterol content. On the other hand, the results from experiments with a monolayer constructed from homogenous synthetic phospholipids indicated an increase in Delta pi change with the increase in the fatty acyl chain length of the phospholipids used to prepare the monolayer. This was confirmed by the results of a pelleting experiment. Adding spectrins into the subphase of raft-like monolayers constructed from DOPC, SM and cholesterol (1/1/1) induced an increase in surface pressure. The Delta pi change values were, however, much smaller than those observed in the case of a natural PEW (6/4) monolayer. An increased binding capacity for spectrins of liposomes prepared from a "raft-like" mixture of lipids could also be concluded from the pelleting assay. In conclusion, we suggest that the effect of membrane lipid fluidity on spectrin-phospholipid interactions is not simple but depends on how it is regulated, i.e., by cholesterol content or by the chemical structure of the membrane lipids. (c) 2005 Elsevier B.V. All rights reserved.