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：
8827384
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

DESCRIPTION (provided by applicant): 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 edge; (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.

描述（由申请人提供）：细胞迁移驱动组织形态发生、免疫反应和癌症转移等关键生物事件。我们最近的数据令人惊讶地表明，迁移过程中细胞前缘的形成和功能关键取决于精氨酸化，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中，我们已经证明，实验性精氨酸化β肌动蛋白可以在很大程度上恢复缺乏精氨酸化酶ATE1的小鼠胚胎成纤维细胞的细胞前缘功能。在我们正在进行的研究中，以确定β肌动蛋白的N端精氨酰化如何促进板状伪足的形成和定向细胞迁移，我们进行了新的观察，即精氨酰化β肌动蛋白的一个重要子集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。 γ 肌动蛋白在氨基酸水平上与 β 肌动蛋白有 99% 的同一性，但其 mRNA 序列却有 13% 的差异。我们已经表明，这种差异直接导致更快的翻译速度 β 肌动蛋白，并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。还已知，邮政编码介导的 β 肌动蛋白 mRNA 靶向调节其前沿定位，并且与精氨酰化一样，对于定向细胞迁移至关重要。我们假设 mRNA 介导的 β 肌动蛋白 N 末端精氨酸化调节通过促进细胞前缘的肌动蛋白聚合来独特地调节细胞迁移过程中的肌动蛋白功能。在本提案中，我们将通过三个具体目标来检验这一假设： (1) 检验β肌动蛋白精氨酸化促进细胞前缘肌动蛋白聚合的假设； (2) 检验β肌动蛋白功能仅受其mRNA编码区和非编码区调节的假设； (3)检验这种调节与细胞迁移过程中细胞内精氨酰化活性的调节相结合的假设。这些实验将解决通过调节肌动蛋白的特性和 mRNA 结构来控制细胞极化和运动的新调节机制，并最终将在重要生理事件期间细胞迁移的靶向功能研究提高到一个新的水平。