Differential localization of aquaporin-2 and glucose transporter 4 in polarized MDCK cells
Differential localization of aquaporin-2 and glucose transporter 4 in polarized MDCK cells
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DOI：
10.1007/s00418-006-0264-4
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发表时间：
2007-03-01
影响因子：
2.3
通讯作者：
Takata, Kuniaki
中科院分区：
文献类型：
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作者：
Hasegawa, Takahiro;Matsuzaki, Toshiyuki;Takata, Kuniaki
膜水通道水通道蛋白 2 (AQP2) 和葡萄糖转运蛋白 4 (GLUT4) 表现出一个共同特征，即它们储存在细胞内储存室中，并在激素刺激下易位至质膜。我们通过免疫荧光显微镜比较了稳定转染人 AQP2 (MDCK-hAQP2) 的极化 Madin-Darby 犬肾细胞中 AQP2 和 GLUT4 的细胞内定位和运输。当在 MDCK-hAQP2 细胞中表达时，GLUT4 和 GLUT4-EGFP 主要位于靠近高尔基体及其内部的核周区域，类似于脂肪细胞和肌细胞中的内源性 GLUT4。此外，GLUT4偶尔出现在EEA1阳性的早期内体中。另一方面，AQP2 被隔离在顶端下 Rab11 阳性囊泡中。在基础状态下，GLUT4的细胞内储存位点与AQP2不同。 Forskolin 诱导 AQP2 从顶端下储存囊泡易位至顶端质膜，这并不影响 GLUT4 定位。当毛喉素被洗掉时，AQP2 首先从顶端质膜被回收到早期内体，在那里它与 GLUT4 部分共定位。然后将 AQP2 转移至 Rab11 阳性储存囊泡中。这些结果表明，AQP2 和 GLUT4 从质膜回收后共享一个公共区室，但在极化 MDCK-hAQP2 细胞中，它们的储存区室彼此不同。
Membrane water channel aquaporin-2 (AQP2) and glucose transporter 4 (GLUT4) exhibit a common feature in that they are stored in intracellular storage compartments and undergo translocation to the plasma membrane upon hormonal stimulation. We compared the intracellular localization and trafficking of AQP2 and GLUT4 in polarized Madin-Darby canine kidney cells stably transfected with human AQP2 (MDCK-hAQP2) by immunofluorescence microscopy. When expressed in MDCK-hAQP2 cells, GLUT4 and GLUT4-EGFP were predominantly localized in the perinuclear region close to and within the Golgi apparatus, similar to endogenous GLUT4 in adipocytes and myocytes. In addition, GLUT4 was occasionally seen in EEA1-positive early endosomes. AQP2, on the other hand, was sequestered in subapical Rab11-positive vesicles. In the basal state, the intracellular storage site of GLUT4 was distinct from that of AQP2. Forskolin induced translocation of AQP2 from the subapical storage vesicles to the apical plasma membrane, which did not affect GLUT4 localization. When forskolin was washed out, AQP2 was first retrieved to early endosomes from the apical plasma membrane, where it was partly colocalized with GLUT4. AQP2 was then transferred to Rab11-positive storage vesicles. These results show that AQP2 and GLUT4 share a common compartment after retrieval from the plasma membrane, but their storage compartments are distinct from each other in polarized MDCK-hAQP2 cells.