Effects of charge on membrane processing in the proximal nephron.
Effects of charge on membrane processing in the proximal nephron.
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电荷对近端肾单位膜处理的影响。
DOI：
10.1152/ajpcell.1989.256.2.c304
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发表时间：
1989
期刊：
影响因子：
--
通讯作者：
Zikos,D
中科院分区：
文献类型：
--
作者：
Peterson,DR;Kubillus,S;Binstock,W;Zikos,D
为了研究分子电荷对肾小管细胞膜处理的影响，在微灌注的近端肾单位段中，阳离子和阴离子铁蛋白的分布是其特征。在近端小管灌注的前7分钟期间，观察到阳离子铁蛋白1）结合于刷状缘膜，2）在顶部定位的囊泡和空泡中，3）在溶酶体中，4）在基底外侧质膜附近的囊泡中，以及5）结合于基底外侧质膜。与阴离子铁蛋白相比，阳离子铁蛋白的分布特征为：1）溶酶体的相对颗粒密度较小，2）颗粒积聚在顶部细胞质囊泡和空泡的扩大池中，3）到达基底外侧质膜的颗粒数量较多。在孵育过程中，直接在分离的肾皮质微绒毛的存在下，阳离子铁蛋白的结合显着增加，pH值从8.0降低到4.5，并大于阴离子铁蛋白，这与pH值变化不大。数据表明，内吞物质的分子电荷影响路由和膜处理在近端肾小管细胞，这表明它们的膜结合特性可能影响运输模式。
To examine the effects of molecular charge on membrane processing in renal tubular cells, the distribution of cationic and anionic ferritin was characterized in microperfused proximal nephron segments. During the first 7 min of proximal tubule perfusion, cationic ferritin was observed 1) bound to the brush-border membrane, 2) in apically positioned vesicles and vacuoles, 3) in lysosomes, 4) in vesicles adjacent to the basolateral plasmalemma, and 5) bound to the basolateral plasmalemma. Compared with anionic ferritin, the distribution of cationic ferritin was characterized by 1) a smaller relative grain density for lysosomes, 2) an accumulation of granules in an enlarged pool of apical cytoplasmic vesicles and vacuoles, and 3) a greater number of granules reaching the basolateral plasmalemma. During incubation directly in the presence of isolated renal cortical microvilli, binding of cationic ferritin increased significantly as pH was lowered from 8.0 to 4.5 and was greater than that of anionic ferritin, which varied little with pH. The data indicate that the molecular charge of endocytosed substances affects routing and membrane processing in proximal tubular cells, suggesting that their membrane-binding characteristics may influence transport patterns.