Integral protein linkage and the bilayer-skeletal separation energy in red blood cells
Integral protein linkage and the bilayer-skeletal separation energy in red blood cells
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DOI：
10.1529/biophysj.108.129163
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发表时间：
2008-08-15
影响因子：
3.4
通讯作者：
Waugh, Richard E.
中科院分区：
文献类型：
--
作者：
Butler, James;Mohandas, Narla;Waugh, Richard E.
红细胞中脂质双层膜通过其与下层膜相关细胞骨架的结合而稳定，长期以来被认为是红细胞正常功能的关键。骨架和双分子层之间的主要连接之一是通过带3（将阴离子转运穿过细胞表面的完整膜蛋白）和膜骨架元件（包括锚蛋白、内收蛋白、血影蛋白和骨架的连接复合物）之间的连接。在这里，我们使用膜系链的形成加上荧光标记的膜组件，以检查在稳定的双层骨骼协会带3的重要性。在来自带3缺陷的患者的膜中，与双层骨架相关的能量约为零，而当带3通过与单克隆抗体R10连接而固定时，缔合能量约加倍。系链的荧光图像显示，正常细胞表面上的条带3的大约40%可以被拉入系链中，证实了系链形成期间膜组分的侧向分离。这些结果证实了带3在稳定红细胞中的双层-骨骼缔合中的关键作用。
Stabilization of the lipid bilayer membrane in red blood cells by its association with an underlying membrane-associated cytoskeleton has long been recognized as critical for proper red blood cell function. One of the principal connections between skeleton and bilayer is via linkages between band 3, the integral membrane protein that transports anions across the cell surface, and membrane skeletal elements including ankyrin, adducin, spectrin, and the junctional complex of the skeleton. Here, we use membrane tether formation coupled with fluorescent labeling of membrane components to examine the importance of band 3 in stabilizing the bilayer-skeletal association. In membranes from a patient deficient in band 3, the energy associated with the bilayer skeleton is approximately zero, whereas when band 3 is immobilized by ligation with the monoclonal antibody R10, the energy of association approximately doubles. Fluorescence images of tethers reveal that similar to 40% of the band 3 on the normal cell surface can be pulled into the tether, confirming a lateral segregation of membrane components during tether formation. These results validate a critical role for band 3 in stabilizing the bilayer-skeletal association in red cells.