Regulation of actin during cell migration

细胞迁移过程中肌动蛋白的调节

基本信息

批准号：
8611459
负责人：
Anna S Kashina
金额：
$ 30.4万
依托单位：
UNIVERSITY OF PENNSYLVANIA
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-04-01 至 2018-02-28
项目状态：
已结题

项目摘要

Project Summary Cell migration drives such key biological events as tissue morphogenesis, immune response, and cancer metastases. Our recent data surprisingly show that the formation and function of the cell leading edge during migration critically depends on arginylation, a relatively unexplored posttranslational modification. Moreover, in cell-based phenotype rescue experiments, we have shown that experimentally arginylated beta actin can largely restore cell leading edge function in mouse embryonic fibroblasts lacking the arginylation enzyme ATE1. In our ongoing studies to determine how N-terminal arginylation of beta actin contributes to lamellipodia formation and directed cell migration, we have made the novel observations that a prominent subset of arginylated beta actin is targeted to the cell leading edge during migration. Moreover, our data demonstrate that beta actin arginylation is selectively regulated by its mRNA sequence rather than its protein structure. In support, gamma actin, which is 99% identical to beta actin at the amino acid level, differs by 13% in its mRNA sequence. We have shown that this difference is directly responsible for faster translation rate of beta actin and leads to its selective arginylation through a novel mechanism coupled to protein ubiquitination. It is also known that zipcode-mediated beta actin mRNA targeting regulates its leading edge localization and, like arginylation, is essential for directional cell migration. We hypothesize that mRNA-mediated regulation of N-terminal arginylation of beta actin uniquely regulates actin function during cell migration by facilitating actin polymerization at the cell leading edge. In this proposal, we will test this hypothesis through three specific aims that will: (1) test the hypothesis that beta actin arginylation facilitates actin polymerization at the cell leading egde; (2) test the hypothesis that beta actin function is uniquely regulated by coding and noncoding regions of its mRNA; and (3) test the hypothesis that this regulation is coupled to modulation of intracellular arginylation activity during cell migration. These experiments will address a novel regulatory mechanism controlling cell polarization and motility through modulating actin's properties and mRNA structure and will ultimately enable a new level of targeted functional studies of cell migration during essential physiological events.

项目概要细胞迁移驱动组织形态发生、免疫反应和癌症等关键生物事件转移。我们最近的数据令人惊讶地表明，细胞前沿的形成和功能迁移主要取决于精氨酰化，这是一种相对未经探索的翻译后修饰。此外，在基于细胞的表型拯救实验，我们已经证明实验精氨酸化的β肌动蛋白可以很大程度上恢复缺乏精氨酸化酶的小鼠胚胎成纤维细胞的细胞前缘功能 ATE1。我们正在进行的研究旨在确定 β 肌动蛋白的 N 末端精氨酸化如何促进片状伪足形成和定向细胞迁移，我们进行了新的观察，即一个突出的子集精酰化 β 肌动蛋白在迁移过程中靶向细胞前缘。此外，我们的数据表明 β 肌动蛋白精氨酸化是由其 mRNA 序列而不是其蛋白质结构选择性调节的。在支持，γ 肌动蛋白，在氨基酸水平上与 β 肌动蛋白有 99% 的相同性，但其 mRNA 存在 13% 的差异顺序。我们已经表明，这种差异直接导致β肌动蛋白和通过与蛋白质泛素化耦合的新机制导致其选择性精氨酸化。据了解，还邮政编码介导的 β 肌动蛋白 mRNA 靶向调节其前沿定位，并且与精氨酸化一样，对于定向细胞迁移至关重要。我们假设 mRNA 介导的 N 末端调控 β 肌动蛋白的精氨酸化通过促进肌动蛋白独特地调节细胞迁移过程中的肌动蛋白功能聚合发生在细胞前缘。在这个提案中，我们将通过三个具体目标来检验这个假设这将：（1）检验β肌动蛋白精氨酸化促进细胞前导肌动蛋白聚合的假设埃格德； (2)检验β肌动蛋白功能唯一受编码区和非编码区调节的假设它的mRNA； (3) 检验这一调节与细胞内精氨酸化调节相关的假设细胞迁移过程中的活性。这些实验将解决控制细胞的新调控机制通过调节肌动蛋白的特性和 mRNA 结构来实现极化和运动，最终使重要生理事件期间细胞迁移的靶向功能研究达到新水平。