...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Proceedings of the National Academy of Sciences of the United States of America >Structural Model And Functional Significance Of Ph-dependent Talin-actin Binding For Focal Adhesion Remodeling
【24h】

Structural Model And Functional Significance Of Ph-dependent Talin-actin Binding For Focal Adhesion Remodeling

机译：Ph依赖的塔林-肌动蛋白结合的局灶性黏附重塑的结构模型和功能意义。

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

Actin filament binding by the focal adhesion (FA)-associated protein talin stabilizes cell-substrate adhesions and is thought to be rate-limiting in cell migration. Although F-actin binding by talin is known to be pH-sensitive in vitro, with lower affinity at higher pH, the functional significance of this pH dependence is unknown. Because increased intracellular pH (pH_i) promotes cell migration and is a hallmark of metastatic carcinomas, we asked whether it increases FA remodeling through lower-affinity talin-actin binding. Talin contains several actin binding sites, but we found that only the COOH-terminal USH-I/LWEQ module showed pH-depen-dent actin binding, with lower affinity and decreased maximal binding at higher pH. Molecular dynamics simulations and NMR of this module revealed a structural mechanism for pH-dependent actin binding. A cluster of titratable amino acids with upshifted pK_a values, including His-2418, was identified at one end of the five-helix bundle distal from the actin binding site. Protonation of His-2418 induces changes in the conformation and dynamics of the remote actin binding site. Structural analyses of a mutant talin-H2418F at pH 6.0 and 8.0 suggested changes different from the WT protein, and we confirmed that actin binding by talin-H2418F was relatively pH-insensitive. In motile fibroblasts, increasing pH[ decreased FA lifetime and increased the migratory rate. However, expression of talin-H2418F increased lifetime 2-fold and decreased the migratory rate. These data identify a molecular mechanism for pH-sensitive actin binding by talin and suggest that FA turnover is pH-dependent and in part mediated by pH-dependent affinity of talin for binding actin.
机译：肌动蛋白丝通过粘着斑粘附（FA）相关蛋白talin的结合稳定了细胞-基质的粘附，并被认为是细胞迁移的速率限制。尽管已知talin与F-肌动蛋白的结合在体外对pH敏感，但在较高pH下亲和力较低，但这种pH依赖性的功能意义尚不清楚。因为增加的细胞内pH（pH_i）促进细胞迁移，并且是转移性癌的标志，所以我们询问它是否通过较低亲和力的塔林-肌动蛋白结合而增加FA重塑。塔林含有几个肌动蛋白结合位点，但我们发现只有COOH末端的USH-I / LWEQ模块显示出pH依赖性的肌动蛋白结合，亲和力较低，在较高的pH值下最大结合力降低。该模块的分子动力学模拟和NMR揭示了pH依赖性肌动蛋白结合的结构机理。在肌动蛋白结合位点远端的五螺旋束的一端鉴定出一组可滴定氨基酸，其pK_a值上移，包括His-2418。 His-2418的质子化诱导远程肌动蛋白结合位点的构象和动力学变化。结构突变的talin-H2418F在pH 6.0和8.0的结构分析表明，该变化不同于野生型蛋白，并且我们证实talin-H2418F与肌动蛋白的结合对pH值不敏感。在能动的成纤维细胞中，增加pH [会降低FA的寿命并增加迁移率。但是，talin-H2418F的表达使寿命延长了2倍，并降低了迁移率。这些数据确定了塔林与pH敏感肌动蛋白结合的分子机制，并表明FA周转是pH依赖性的，并且部分由塔林对结合肌动蛋白的pH依赖性亲和力介导。

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