Regulation of band 3 rotational mobility by ankyrin in intact human red cells
Regulation of band 3 rotational mobility by ankyrin in intact human red cells
复制标题
DOI：
10.1021/bi981825c
复制
发表时间：
1998-12-22
期刊：
影响因子：
2.9
通讯作者：
Golan, DE
中科院分区：
文献类型：
--
作者：
Cho, MR;Eber, SW;Golan, DE
锚蛋白突变以及血影蛋白和锚蛋白的联合缺乏是遗传性球形红细胞增多症（HS）患者红细胞（RBC）的突出特征。带3是人类RBC膜中最丰富的整合蛋白。先前的研究表明，在患有严重常染色体隐性遗传性HS和选择性血影蛋白缺乏症的患者的RBC中，带3的横向移动性而不是旋转移动性增加。这些观察结果与侧向流动性限制的空间位阻模型一致。在这里，我们使用荧光光漂白恢复和偏振荧光耗尽技术来测量来自六名患有HS、锚蛋白突变和血影蛋白和锚蛋白联合缺陷的患者的完整RBC中带3的侧向和旋转流动性。正如空间位阻模型所预测的，谱带3的横向扩散速率在血影蛋白和血管紧张素缺乏的红细胞中比在对照细胞中更大，并且增加的幅度与血影蛋白缺乏的程度相关。然而，与HS和选择性血影蛋白缺乏症患者的RBC不同，具有锚蛋白突变的HS RBC表现出带3旋转扩散的显著增加。增加的幅度与锚蛋白/带3的比例和去污剂提取后保留在膜骨架中的带3的分数成反比。这些数据表明，锚蛋白缺乏放松旋转约束的主要（缓慢旋转）人口的带3分子，带3旋转的增加可能是由于带3从锚蛋白上的低亲和力结合位点的释放。
Ankyrin mutations and combined spectrin and ankyrin deficiency are prominent features of red blood cells (RBCs) in patients with hereditary spherocytosis (HS), Band 3 is the most abundant integral protein in the human RBC membrane. Previous studies have shown that the lateral mobility, but not the rotational mobility, of band 3 is increased in RBCs from patients with severe autosomal recessive HS and selective spectrin deficiency. These observations are consistent with the steric hindrance model of lateral mobility restriction, Here we use the fluorescence photobleaching recovery and polarized fluorescence depletion techniques to measure the lateral and rotational mobility of band 3 in intact RBCs from six patients with HS, ankyrin mutations, and combined spectrin and ankyrin deficiency. As predicted by the steric hindrance model, the lateral diffusion rate of band 3 is greater in spectrin- and ankyrin-deficient RBCs than in control cells, and the magnitude of the increase correlates with the degree of spectrin deficiency. Unlike RBCs from patients with HS and selective spectrin deficiency, however, HS RBCs with ankyrin mutations exhibit a marked increase in band 3 rotational diffusion. The magnitude of the increase correlates inversely with the ankyrin/band 3 ratio and with the fraction of band 3 retained in the membrane skeleton following detergent extraction. These data suggest that ankyrin deficiency relaxes rotational constraints on the major (slowly rotating) population of band 3 molecules, Increases in band 3 rotation could be due to release of band 3 from low-affinity binding sites on ankyrin.