Presence and localization of aquaporin-6 in rat parotid acinar cells
Presence and localization of aquaporin-6 in rat parotid acinar cells
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DOI：
10.1007/s00441-007-0558-4
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发表时间：
2008-04-01
影响因子：
3.6
通讯作者：
Sugiya, Hiroshi
中科院分区：
文献类型：
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作者：
Matsuki-Fukushima, Miwako;Hashimoto, Sadamitsu;Sugiya, Hiroshi
水通道蛋白（AQP）是一种膜蛋白，作为水和小分子溶质跨膜转运的通道。在哺乳动物细胞中，已经鉴定了13种亚型（AQP 0 -12），这些亚型在各种细胞类型和组织中表现出独特的表达模式。在这些亚型中，AQP 6被认为不是作为水通道，而是作为阴离子通道。我们研究了大鼠腮腺腺泡细胞中AQP 6的存在和定位。AQP 6 mRNA在这些细胞中检测到通过使用逆转录/聚合酶链反应，和Western印迹分析确定了一个蛋白带，与抗AQP 6抗体在膜部分和分泌颗粒膜反应。为了定位AQP 6，我们使用抗AQP 6抗体进行组织学免疫检测。在共聚焦显微镜下，我们观察到腮腺腺泡细胞紧密连接附近的阳性免疫反应。免疫标记法检测到AQP 6的紧密连接附近和周围的分泌颗粒膜。免疫电子显微镜证实了AQP 6的存在下，分离的分泌颗粒的膜。这些结果表明，AQP 6参与了水和阴离子的运输附近的紧密连接和分泌颗粒膜在大鼠腮腺腺泡细胞的质膜。
Aquaporins (AQPs) are integral membrane proteins that function as channels for the transfer of water and small solutes across membranes. In mammalian cells, 13 isoforms (AQP0-12) have been identified, and these exhibit unique patterns of expression in various cell types and tissues. Among these isoforms, AQP6 is considered to function not as water channel, but as an anion channel. We investigated the presence and localization of AQP6 in rat parotid acinar cells. AQP6 mRNA was detected in these cells by using reverse transcription/polymerase chain reaction, and Western blotting analysis identified a protein band that reacted with an anti-AQP6 antibody in the membrane fraction and secretory granule membrane. In order to localize AQP6, we used the anti-AQP6 antibody for histological immunodetection. Under confocal microscopy, we observed positive immunoreactions near the tight junctions of parotid acinar cells. Immunolabeling of ultrathin cryosections detected AQP6 near tight junctions and around secretory granule membranes. Immunoelectron microscopy confirmed the presence of AQP6 in the membranes of isolated secretory granules. These results suggest that AQP6 participates in water and anion transport in plasma membranes near tight junctions and secretory granule membranes in rat parotid acinar cells.