• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>American Journal of Physiology >Membrane organization and function of M1 and M23 isoforms of aquaporin-4 in epithelial cells.
【24h】

Membrane organization and function of M1 and M23 isoforms of aquaporin-4 in epithelial cells.

机译：上皮细胞中aquaporin-4的M1和M23亚型的膜组织和功能。

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Aquaporin-4 (AQP4) water channels exist as heterotetramers of M1 and M23 splice variants and appear to be present in orthogonal arrays of intramembraneous particles (OAPs) visualized by freeze-fracture microscopy. We report that AQP4 forms OAPs in rat gastric parietal cells but not in parietal cells from the mouse or kangaroo rat. Furthermore, the organization of principal cell OAPs in Brattleboro rat kidney is perturbed by vasopressin (arginine vasopressin). Membranes of LLC-PK(1) cells expressing M23-AQP4 showed large, abundant OAPs, but none were detectable in cells expressing M1-AQP4. Measurements of osmotic swelling of transfected LLC-PK(1) cells using videomicroscopy, gave osmotic water permeability coefficient (P(f)) values (in cm/s) of 0.018 (M1-AQP4), 0.019 (M23-AQP4), and 0.003 (control). Quantitative immunoblot and immunofluorescence showed an eightfold greater expression of M1- over M23-AQP4 in the cell lines, suggesting that single-channel p(f) (cm(3)/s) is much greater for the M23 variant. Somatic fusion of M1- and M23-AQP4 cells (P(f) = 0.028 cm/s) yielded OAPs that were fewer and smaller than in M23 cells alone, and M1-to-M23 expression ratios ( approximately 1:4) normalized to AQP4 in M1 or M23 cells indicated a reduced single-channel p(f) for the M23 variant. Expression of an M23-AQP4-Ser(111E) mutant produced approximately 1.5-fold greater single-channel p(f) and OAPs that were up to 2.5-fold larger than wild-type M23-AQP4 OAPs, suggesting that a putative PKA phosphorylation site Ser(111) is involved in OAP formation. We conclude that the higher-order organization of AQP4 in OAPs increases single-channel osmotic water permeability by one order of magnitude and that differential cellular expression levels of the two isoforms could regulate this organization.
机译：Aquaporin-4（AQP4）水通道以M1和M23剪接变体的异四聚体形式存在，并且似乎存在于通过冷冻断裂显微镜观察的正交膜内颗粒（OAP）阵列中。我们报告说，AQP4在大鼠胃壁细胞中形成OAP，但不在小鼠或袋鼠大鼠的壁细胞中形成OAP。此外，血管加压素（精氨酸加压素）干扰了布拉特伯勒大鼠肾脏中主要细胞OAP的组织。表达M23-AQP4的LLC-PK（1）细胞膜显示大量的OAP，但在表达M1-AQP4的细胞中未检测到。使用视频显微镜测量转染的LLC-PK（1）细胞的渗透溶胀，得出渗透水渗透系数（P（f））值（cm / s）为0.018（M1-AQP4），0.019（M23-AQP4）和0.003（对照）。定量免疫印迹和免疫荧光显示细胞系中M1-的表达超过M23-AQP4的八倍，这表明M23变体的单通道p（f）（cm（3）/ s）更大。 M1和M23-AQP4细胞的体细胞融合（P（f）= 0.028 cm / s）产生的OAP比单独的M23细胞少且小，并且M1与M23的表达比（约1：4）标准化为M1或M23细胞中的AQP4表示M23变体的单通道p（f）降低。 M23-AQP4-Ser（111E）突变体的表达产生的单通道p（f）和OAP约比野生型M23-AQP4 OAP约高2.5倍，是后者的1.5倍，这表明推测的PKA磷酸化站点Ser（111）参与OAP的形成。我们得出的结论是，OAP中AQP4的高级组织将单通道渗透水渗透性提高了一个数量级，并且两种同工型的不同细胞表达水平可以调节该组织。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号