Na+,K+-adenosine triphosphatase polarity in retinal photoreceptors: a role for cytoskeletal attachments.
Na+,K+-adenosine triphosphatase polarity in retinal photoreceptors: a role for cytoskeletal attachments.
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DOI：
10.1083/jcb.109.4.1483
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发表时间：
1989-10
期刊：
影响因子：
--
通讯作者：
Adler R
中科院分区：
文献类型：
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作者：
Madreperla SA;Edidin M;Adler R
我们使用分离的胚胎感光细胞作为模型系统来检查负责不对称 Na+,K+-ATPase (ATPase) 分布的发育和维持的机制。光感受器前体在培养开始时呈圆形且无加工，其结构和分子特性与体内光感受器细胞相似。被抗 ATP 酶抗体识别的 ATP 酶分布在圆形光感受器前体的整个表面上。随着细胞的发育，ATP 酶逐渐集中在内节（完整视网膜的细胞中）。这种现象发生在缺乏细胞间接触的情况下发育的细胞中。 ATP 酶极性的发展与膜中可移动的 ATP 酶分子分数的减少（通过荧光光漂白恢复确定）以及去垢剂提取后仍与细胞结合的 ATP 酶分数的增加相关。在未成熟和发育的光感受器中，移动 ATP 酶分数的大小与去污剂可提取分数的大小非常一致。 α 血影蛋白和 ATP 酶免疫反应材料的分布在质量上看起来相似，定量图像分析显示血影蛋白和 Na+,K+-ATP 酶免疫荧光沿着细长光感受器的长轴具有相似的梯度。此外，α 血影蛋白和 ATP 酶的洗涤剂可萃取性随着 pH 值或 KCl 浓度的变化而表现出类似的变化。在用细胞骨架抑制剂（例如诺考达唑）处理的培养物中，ATP酶去污剂可提取的和可移动的级分没有变化。这些数据与不对称分布的、含有血影蛋白的皮层下细胞骨架在光感受器内段中Na+,K+-ATP酶优先积累中的作用一致。
We have used isolated embryonic photoreceptor cells as a model system with which to examine the mechanisms responsible for the development and maintenance of asymmetric Na+,K+-ATPase (ATPase) distribution. Photoreceptor precursors, which appear round and process free at culture onset, develop structural and molecular properties similar to those of photoreceptor cells in vivo. ATPase, recognized by an anti- ATPase antibody, is distributed over the entire surface of round photoreceptor precursors. As the cells develop, ATPase becomes progressively concentrated in the inner segment (where it is found in cells of the intact retina). This phenomenon occurs in cells developing in the absence of intercellular contacts. The development of ATPase polarity correlates with a decrease in the fraction of ATPase molecules that are mobile in the membrane (as determined by fluorescence photobleaching recovery), as well as with an increase in the fraction of ATPase that remains associated with the cells after detergent extraction. The magnitudes of the mobile ATPase fractions agree well with those of the detergent-extractable fractions in both the immature and developed photoreceptors. The distribution of alpha spectrin and ATPase-immunoreactive materials appeared qualitatively similar, and quantitative image analysis showed similar gradients of spectrin and Na+,K+-ATPase immunofluorescence along the long axis of elongated photoreceptors. Moreover, detergent extractability of alpha spectrin and the ATPase showed similar modifications in response to changes in pH or KCl concentration. ATPase detergent-extractable and mobile fractions were not changed in cultures treated with cytoskeletal inhibitors such as nocodazole. These data are consistent with a role for an asymmetrically distributed, spectrin-containing subcortical cytoskeleton in the preferential accumulation of Na+,K+-ATPase in the photoreceptor inner segment.