H(+)V-ATPase-dependent luminal acidification in the kidney collecting duct and the epididymis/vas deferens: vesicle recycling and transcytotic pathways.
H(+)V-ATPase-dependent luminal acidification in the kidney collecting duct and the epididymis/vas deferens: vesicle recycling and transcytotic pathways.
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发表时间：
2000
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通讯作者：
D. Brown;S. Breton
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作者：
D. Brown;S. Breton
许多脊椎动物的转运上皮细胞含有特征性的“富含线粒体”细胞，这些细胞在质膜和细胞内囊泡上表达高水平的液泡质子泵ATP酶（H(+)V-ATP酶）。在肾皮质中，A 细胞和 B 细胞分别参与远端肾单位和集合管中的质子分泌和碳酸氢盐分泌。 A 细胞的顶端质膜和细胞内囊泡上有 H(+)V-ATP 酶，而 B 细胞中 H(+)V-ATP 酶的细胞位置可以是顶端、基底外侧、双极或弥漫性。大鼠附睾和输精管还含有一群独特的富含H(+)V-ATP酶的上皮细胞。这些细胞参与产生低腔内 pH 值，这参与精子成熟并在精子通过附睾和输精管期间维持精子处于不动状态。在肾脏和生殖道中，富含 H(+)V-ATPase 的细胞具有很高的顶膜回收率。 H(+)V-ATP酶分子在囊泡中的细胞表面和细胞质之间转运，囊泡具有由H(+)V-ATP酶的外周V(1)亚基形成的明确“外壳”结构。此外，我们提出 B 型嵌入细胞具有转胞吞途径，使它们能够将 H(+)V-ATPase 分子从顶端质膜域运送到基底外侧质膜域。这一假设得到了数据的支持，数据显示 A 细胞和 B 细胞对于 LGP120（一种溶酶体糖蛋白）具有不同的细胞内运输途径。 LGP120 在 B 细胞的基底外侧质膜和溶酶体中均被发现，而在 A 细胞的质膜中未检测到 LGP120。我们认为 B 嵌入细胞中 H(+)V-ATP 酶的“极性反转”是由生理调节的转胞吞途径介导的，该途径可能与某些其他细胞类型中存在的途径相似。
Many vertebrate transporting epithelia contain characteristic 'mitochondria-rich' cells that express high levels of a vacuolar proton-pumping ATPase (H(+)V-ATPase) on their plasma membrane and on intracellular vesicles. In the kidney cortex, A-cells and B-cells are involved in proton secretion and bicarbonate secretion, respectively, in the distal nephron and collecting duct. A-cells have an H(+)V-ATPase on their apical plasma membrane and on intracellular vesicles, whereas the cellular location of the H(+)V-ATPase can be apical, basolateral, bipolar or diffuse in B-cells. The rat epididymis and vas deferens also contain a distinct population of H(+)V-ATPase-rich epithelial cells. These cells are involved in generating a low luminal pH, which is involved in sperm maturation and in maintaining sperm in an immotile state during their passage through the epididymis and vas deferens. In both kidney and reproductive tract, H(+)V-ATPase-rich cells have a high rate of apical membrane recycling. H(+)V-ATPase molecules are transported between the cell surface and the cytoplasm in vesicles that have a well-defined 'coat' structure formed of the peripheral V(1) subunits of the H(+)V-ATPase. In addition, we propose that B-type intercalated cells have a transcytotic pathway that enables them to shuttle H(+)V-ATPase molecules from apical to basolateral plasma membrane domains. This hypothesis is supported by data showing that A-cells and B-cells have different intracellular trafficking pathways for LGP120, a lysosomal glycoprotein. LGP120 was found both on the basolateral plasma membrane and in lysosomes in B-cells, whereas no LGP120 was detectable in the plasma membrane of A-cells. We propose that the 'polarity reversal' of the H(+)V-ATPase in B-intercalated cells is mediated by a physiologically regulated transcytotic pathway that may be similar to that existing in some other cell types.