Detergent-resistant membranes in human erythrocytes and their connection to the membrane-skeleton
Detergent-resistant membranes in human erythrocytes and their connection to the membrane-skeleton
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DOI：
10.1007/bf02703669
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发表时间：
2005-06-01
影响因子：
2.9
通讯作者：
Minetti, G
中科院分区：
文献类型：
--
作者：
Ciana, A;Balduini, C;Minetti, G
在细胞膜中，脂质和蛋白质横向分布的局部不均匀性被认为以脂质“筏”的形式存在于体内，富含胆固醇和鞘脂的微结构域，以及特定类别的蛋白质，这些蛋白质似乎在信号转导，细胞-细胞识别，寄生虫或病毒感染和囊泡运输中发挥专门作用。这些结构在操作上被定义为在4 ° C下耐非离子洗涤剂溶解的膜（耐洗涤剂膜，DRM）。这一定义似乎是必要和充分的，尽管可能需要额外的操作（不总是以足够的细节描述）以确保DRM的分离，如机械均质化以及增溶介质的pH和/或离子强度的变化。我们在这里显示的人类红细胞，采用不同的条件可能会导致分离的定性和定量不同的DRM馏分，从而有助于复杂的概念本身的脂筏。富含已报道的脂筏标记物（如flotillin-1、flotillin-2和GM（1））的红细胞DRM的很大一部分通过静电相互作用锚定在血影蛋白膜骨架上，该静电相互作用可被增溶介质的pH值和离子强度的同时增加所破坏。
In cell membranes, local inhomogeneity in the lateral distribution of lipids and proteins is thought to exist in vivo in the form of lipid 'rafts', microdomains enriched in cholesterol and sphingolipids, and in specific classes of proteins, that appear to play specialized roles for signal transduction, cell-cell recognition, parasite or virus infection, and vesicular trafficking. These structures are operationally defined as membranes resistant to solubilization by nonionic detergents at 4 degrees C (detergent-resistant membranes, DRMs). This definition appears to be necessary and sufficient, although additional manoeuvres, not always described with sufficient detail, may be needed to ensure isolation of DRMs, like mechanical homogenization, and changes in the pH and/or ionic strength of the solubilization medium. We show here for the human erythrocyte that the different conditions adopted may lead to the isolation of qualitatively and quantitatively different DRM fractions, thus contributing to the complexity of the notion itself of lipid raft. A significant portion of erythrocyte DRMs enriched in reported lipid raft markers, such as flotillin-1, flotillin-2 and GM(1), is anchored to the spectrin membrane-skeleton via electrostatic interactions that can be disrupted by the simultaneous increase in pH and ionic strength of the solubilization medium.