Involvement of aquaporin-5 water channel in osmoregulation in parotid secretory granules
Involvement of aquaporin-5 water channel in osmoregulation in parotid secretory granules
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DOI：
10.1007/s00232-005-0736-9
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发表时间：
2005-02-01
影响因子：
2.4
通讯作者：
Sugiya, H
中科院分区：
文献类型：
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作者：
Matsuki, N;Hashimoto, S;Sugiya, H
水通道蛋白（Aquaporins，AQP）是一类允许水或非常小的溶质通过的通道蛋白，在需要快速和调节的液体运输的组织中起作用，如肾、肺。和唾液腺。水通道蛋白5（Aquaporin-5，AQP 5）定位于唾液腺腺泡细胞的腔面。本研究探讨了水通道蛋白5在大鼠腮腺分泌颗粒中的表达及其功能。免疫印迹法检测到AQP 5存在于分泌型小管膜上。免疫电镜实验证实AQP 5定位于分泌颗粒膜上。抗AQP 5抗体引起分泌颗粒溶解，但抗水通道蛋白1抗体没有，AQP 1在分泌颗粒膜上未被检测到。当从制备用于悬浮分泌颗粒的溶液中去除氯离子时，抗AQP 5抗体诱导的颗粒溶解被抑制。此外，阴离子通道阻断剂4，4 '-二异硫氰酸二苯乙烯-2，2'-二磺酸可阻断抗AQP 5抗体诱导的分泌颗粒溶解。提示AQP 5在腮腺分泌颗粒膜上表达，并参与腮腺分泌颗粒膜的通透性调节。
Aquaporins (AQPs) are a family of channel proteins that allow water or very small Solutes to pass, functioning in tissues where the rapid and regulated transport of fluid is necessary, Such as the kidney, lung. and salivary glands. Aquaporin-5 (AQP5) has been demonstrated to localize on the luminal Surface of the acinar cells of the salivary glands. In this paper, we investigated the expression and function of AQP5 in the secretory granules of the rat parotid gland. AQP5 was detected in the secretory uranule Membranes by immunoblot analysis. The ummunoelectron microscopy experiments confirmed that AQP5 was to be found in the secretory granule membrane. Anti-AQP5 antibody evoked lysis of the secretory granules but anti-aquaporin-1 antibody did not and AQP1 was not detected in the secretory granule membranes by immunoblot analysis. When chloride ions were removed from the solution prepared for suspending secretory (granules, the granule lysis induced by anti-AQP5 antibody was inhibited. Furthermore, 4,4'-dii'sothiocyanatostilbene-2,2'-di-sulfonic acid, an anion channel blocker, blocked the anti-AQP5 antibody-induced secretory granule lysis. These results suggest that AQP5 is, expressed in the parotid gland secretory granule membrane and is involved in osmoregulation in the secretory granules.