Regulation of cell migration by nucleotide coding sequence and arginylation

通过核苷酸编码序列和精氨酸化调节细胞迁移

基本信息

批准号：
10552132
负责人：
Anna S Kashina
金额：
$ 68.7万
依托单位：
UNIVERSITY OF PENNSYLVANIA
依托单位国家：
美国
项目类别：
财政年份：
2017
资助国家：
美国
起止时间：
2017-09-15 至 2028-02-29
项目状态：
未结题

项目摘要

Cell migration is a critically important process in key biological events such as tissue morphogenesis, immune response, and cancer metastasis. Directional migration of multiple cell types depends on the dense actin network that rapidly forms at the cell leading edge and facilitates its protrusion via polarized elongation of the actin filaments. Our published studies revealed two novel interconnected determinants of the function of actin at the cell leading edge: actin's nucleotide coding sequence and actin arginylation. Using integrated approaches that combine protein biochemistry, cell biology, and mouse transgenesis, work from my lab demonstrated that arginyltransferase (ATE1), the enzyme that arginylates proteins, specifically regulates the function of actin during cell migration and contributes to virtually every physiologic process involving long-range migration and tissue remodeling in mice. These studies drive my research program, which aims to characterize the novel mechanisms of actin regulation by nucleotide coding sequence and arginylation. Our recent data show that N-terminal arginylation of the leading edge actin is a dynamic event that exhibits a rapid response to extracellular stimuli and is essential for maintaining cell migration speed. Moreover, arginylation is highly specific to the ubiquitous and essential β-actin isoform but not to the closely homologous γ-actin in the same cell types. Remarkably, this specificity is determined at the nucleotide level by the mRNA coding sequence, which is responsible for the differential translation rates of different actin isoforms, exerting downstream effects on their folding rates and co-translational ubiquitination. This novel actin regulatory mechanism targets incorrectly arginylated actin isoforms for degradation and ensures that only the fast accumulating β-actin becomes arginylated in cells. Thus, actin arginylation at the cell leading edge is a tightly regulated process that is genetically encoded in its nucleotide sequence, suggesting that arginylation is the primary level of actin regulation that occurs prior to any other actin-dependent event. Uncovering the essential steps of this regulation in actin function and coordination of cell migration in vivo constitutes my long-term research goal.

细胞迁移是组织形态发生、免疫反应和癌症转移等关键生物事件中至关重要的过程，多种细胞类型的定向迁移取决于在细胞前缘快速形成并通过极化伸长促进其突出的致密肌动蛋白网络。我们发表的研究揭示了细胞前缘肌动蛋白功能的两个新的相互关联的决定因素：肌动蛋白的核苷酸编码序列和肌动蛋白精氨酸化使用结合蛋白质的综合方法。在生物化学、细胞生物学和小鼠转基因方面，我的实验室的工作表明，精氨酰转移酶 (ATE1)（一种精氨酸化蛋白质的酶）在细胞迁移过程中特异性调节肌动蛋白的功能，并有助于几乎所有涉及长程迁移和组织重塑的生理过程这些研究推动了我的研究计划，该计划旨在通过核苷酸编码序列和精氨酰化来表征肌动蛋白调节的新机制。前沿肌动蛋白是一种动态事件，对细胞外刺激表现出快速反应，对于维持细胞迁移速度至关重要。此外，精氨酸化对普遍存在且必需的 β-肌动蛋白异构体具有高度特异性，但对密切同源的 γ-肌动蛋白不具有特异性。值得注意的是，这种特异性是在核苷酸水平上由 mRNA 编码序列决定的，该序列导致不同肌动蛋白亚型的翻译率存在差异，并对其折叠产生下游影响。这种新颖的肌动蛋白调节机制针对错误精氨酸化的肌动蛋白异构体进行降解，并确保只有快速积累的β-肌动蛋白在细胞中被精氨酸化。因此，细胞前缘的肌动蛋白精氨酸化是一个严格调控的过程。在其核苷酸序列中进行基因编码，表明精氨酰化是肌动蛋白调节的主要水平，发生在任何其他肌动蛋白依赖性事件之前。揭示肌动蛋白功能调节和体内细胞迁移协调的基本步骤是我的长期研究目标。