Phosphorylation of radixin regulates cell polarity and Mrp-2 distribution in hepatocytes
Phosphorylation of radixin regulates cell polarity and Mrp-2 distribution in hepatocytes
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DOI：
10.1152/ajpcell.00467.2010
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发表时间：
2011-03-01
影响因子：
5.5
通讯作者：
Karvar, Serhan
中科院分区：
文献类型：
--
作者：
Suda, Jo;Zhu, Lixin;Karvar, Serhan
Suda J，朱丽，Karvar S. radixin磷酸化对肝细胞极性和Mrp-2分布的影响。[J] .中国生物医学工程学报，2016,31(4):557 - 557。首次发表于2010年12月15日；doi: 10.1152 / ajpcell.00467.2010。-radixin是肝细胞中主要的ezrin-radixin- moesin （ERM）蛋白，有两个重要的结合域：一个与质膜结合的nh2末端区域和一个与F-actin结合的cooh末端区域，该区域在Thr564位点磷酸化后被构象激活。本研究旨在探讨wifi - b细胞中放射素表达的细胞变化，评估放射素的分布及其对细胞极性的影响。我们使用重组腺病毒表达系统编码radixin野生型和Thr564突变体融合到青色荧光蛋白（CFP），以及传统的免疫染色程序。功能分析进行了定量表征。与内源性根治素类似，腺病毒感染的根治素- cfp野生型和非磷酸化的根治素- cfp - t564a在管状膜液泡的腔室中大量表达，通常与多药耐药相关蛋白2 （Mrp-2）共定位。模拟恒定磷酸化的radixin-CFP-T564D的表达完全不同，很少与小管膜相关。wi - b细胞缺乏分泌反应，T567D放射素主要重新分布到基底外膜，通常以密集的长刺状突起和指状突起的形式出现，细胞极性的改变涉及顶膜标志物的改变。radixin极性分布的差异提示连接蛋白在促进膜表面突起的形成和可塑性方面的作用，也提示radixin可能是肝细胞Mrp-2和细胞极性的组织者和调节者。
Suda J, Zhu L, Karvar S. Phosphorylation of radixin regulates cell polarity and Mrp-2 distribution in hepatocytes. Am J Physiol Cell Physiol 300: C416-C424, 2011. First published December 15, 2010; doi:10.1152/ajpcell.00467.2010.-Radixin, the dominant ezrin-radixin- moesin (ERM) protein in hepatocytes, has two important binding domains: an NH2-terminal region that binds to plasma membrane and a COOH-terminal region that binds to F-actin after a conformational activation by phosphorylation at Thr564. The present studies were undertaken to investigate the cellular changes in expression of radixin in WIF-B cells and to assess radixin distribution and its influence on cell polarity. We used a recombinant adenoviral expression system encoding radixin wild-type and Thr564 mutants fused to cyan fluorescent protein (CFP), as well as conventional immunostaining procedures. Functional analyses were characterized quantitatively. Similar to endogenous radixin, adenovirus-infected radixin-CFP-wild type and nonphosphorylatable radixin-CFP-T564A were found to be expressed heavily in the compartment of canalicular membrane vacuoles, typically colocalizing with multidrug resistance-associated protein 2 (Mrp-2). Expression of radixin-CFP-T564D, which mimics constant phosphorylation, was quite different, being rarely associated with canalicular membranes. The WIF-B cells were devoid of a secretory response, T567D radixin became predominantly redistributed to the basolateral membrane, usually in the form of dense, long spikes and fingerlike projections, and the altered cell polarity involved changes in apical membrane markers. Differences in polar distribution of radixin suggest a role for the linker protein in promoting formation and plasticity of membrane surface projections and also suggest that radixin might be an organizer and regulator of Mrp-2 and cell polarity in hepatocytes.