Localization of MIWC and GLIP water channel homologs in neuromuscular, epithelial and glandular tissues.
Localization of MIWC and GLIP water channel homologs in neuromuscular, epithelial and glandular tissues.
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发表时间：
1995-09
影响因子：
4
通讯作者：
A. Frigeri;M. Gropper;F. Umenishi;M. Kawashima;Dennis Brown;A. Verkman
中科院分区：
文献类型：
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作者：
A. Frigeri;M. Gropper;F. Umenishi;M. Kawashima;Dennis Brown;A. Verkman
最近研究表明，水通道同源物MIWC（mercurial insensitive water channel）和GLIP（glycerol intrinsic protein）共定位于肾集合管基底膜、气管和结肠上皮以及脑软脑膜中。我们在此报告了MIWC和GLIP在大鼠非上皮和腺上皮组织中的广泛免疫定位研究。免疫金电镜证实MIWC和GLIP共定位于肾集合管主细胞基底外侧膜。在其他上皮中，胃壁细胞的基底侧膜、唾液腺和泪腺的排泄小管表达MIWC，膀胱移行上皮和皮肤表皮表达GLIP，而不表达MIWC。在中枢神经系统中，MIWC在衬水管系统的室管膜层中以及在整个脊髓和脑的选定区域中的星形胶质细胞中强烈表达。MIWC在骨骼肌中也以质膜模式表达，但在平滑肌或心肌中不表达。在小肠、睾丸、肝脏、脾脏和神经中均不表达。MIWC的组织特异性表达表明在胃和腺上皮中的流体运输和/或细胞体积调节中起作用。MIWC表达在神经肌肉系统中以及GLIP表达在皮肤和膀胱中的功能作用尚不确定。MIWC表达的特定细胞位点（星形胶质细胞、气管、肌膜、胃壁细胞和肾主细胞）恰好对应于冷冻断裂电子显微镜观察到的正交颗粒阵列（OAP）位点，这表明MIWC可能是OAP蛋白。
It was shown recently that water channel homologs MIWC (mercurial insensitive water channel) and GLIP (glycerol intrinsic protein) colocalized in basolateral membranes of kidney collecting duct, tracheal and colonic epithelia, and in brain pia mater. We report here an extensive immunolocalization study of MIWC and GLIP in non-epithelial and glandular epithelial tissues in rat. Immunogold electron microscopy confirmed colocalization of MIWC and GLIP in basolateral membrane of principal cells in kidney collecting duct. However, in other epithelia, MIWC but not GLIP was expressed in basolateral membrane of parietal cells in stomach, and in excretory tubules of salivary and lacrimal glands; GLIP but not MIWC was expressed in transitional epithelium of urinary bladder and skin epidermis. In the central nervous system, MIWC was strongly expressed in the ependymal layer lining the aqueductal system, and in astrocytes throughout the spinal cord and in selected regions of brain. MIWC was also expressed in a plasma membrane pattern in skeletal, but not smooth or cardiac muscle. Neither protein was expressed in small intestine, testis, liver, spleen and nerve. The tissue-specific expression of MIWC suggests a role in fluid transport and/or cell volume regulation in stomach and glandular epithelia. The functional role of MIWC expression in the neuromuscular system and of GLIP expression in skin and urinary bladder is uncertain. The specific cellular sites of MIWC expression (astrocytes, trachea, sarcolemma, gastric parietal cells and kidney principal cells) correspond exactly to sites where orthogonal arrays of particles (OAPs) have been visualized by freeze-fracture electron microscopy, suggesting that MIWC may be the OAP protein.