Na+/H+ exchange regulatory factor 1 is required for ROMK1 K+ channel expression in the surface membrane of cultured M-1 cortical collecting duct cells.
Na+/H+ exchange regulatory factor 1 is required for ROMK1 K+ channel expression in the surface membrane of cultured M-1 cortical collecting duct cells.
复制标题
Na /H 交换调节因子 1 是培养的 M-1 皮质集合管细胞表面膜中 ROMK1 K 通道表达所必需的。
DOI：
10.1016/j.bbrc.2017.05.104
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发表时间：
2017
影响因子：
3.1
通讯作者：
Manabu Kubokawa.
中科院分区：
文献类型：
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作者：
Takashi Suzuki;Kazuyoshi Nakamura;Taira Mayanagi;Kenji Sobue;Manabu Kubokawa.
ROMK 1 K+通道是ROMK通道家族的成员，是肾皮质集合管（CCD）中K+分泌途径的主要候选者。ROMK 1在其C-末端具有PDZ结构域结合基序，其被认为是通过与Na+/H+交换调节因子（NHERF）1和NHERF 2支架蛋白相互作用的ROMK 1表达的调节剂。虽然NHERF 1是ROMK 1 K+通道的潜在结合伴侣，但NHERF 1与K+通道活性之间的相互作用仍不清楚。因此，在这项研究中，我们敲低培养的M-1细胞来自小鼠CCD和调查的表面表达和K+通道电流在这些细胞与EGFP-ROMK 1外源转染后。如细胞生物素化测定所示，NHERF 1敲低导致ROMK 1的表面表达减少。利用膜片钳技术，我们进一步发现，在敲低的细胞中，每个补丁膜的活性通道的数量和Ba 2+敏感的全细胞K+电流减少，这表明在NHERF 1敲低的细胞中，K+电流减少伴随着ROMK 1的表面表达减少。我们的研究结果提供了证据表明，NHERF 1介导的K+电流活性，通过加速表面表达的ROMK 1 K+通道在M-1细胞。
The ROMK1 K+channel, a member of the ROMK channel family, is the major candidate for the K+secretion pathway in the renal cortical collecting duct (CCD). ROMK1 possesses a PDZ domain-binding motif at its C-terminus that is considered a modulator of ROMK1 expression via interaction with Na+/H+exchange regulatory factor (NHERF) 1 and NHERF2 scaffold protein. Although NHERF1 is a potential binding partner of the ROMK1 K+channel, the interaction between NHERF1 and K+channel activity remains unclear. Therefore, in this study, we knocked down NHERF1 in cultured M-1 cells derived from mouse CCD and investigated the surface expression and K+channel current in these cells after exogenous transfection with EGFP-ROMK1. NHERF1 knockdown resulted in reduced surface expression of ROMK1 as indicated by a cell biotinylation assay. Using the patch-clamp technique, we further found that the number of active channels per patched membrane and the Ba2+-sensitive whole-cell K+current were decreased in the knockdown cells, suggesting that reduced K+current was accompanied by decreased surface expression of ROMK1 in the NHERF1 knockdown cells. Our results provide evidence that NHERF1 mediates K+current activity through acceleration of the surface expression of ROMK1 K+channels in M-1 cells.