Myosin II Dynamics and Assembly in Mammalian Cells

描述(由申请人提供)：这项提案侧重于破译肌球蛋白II在胞质分裂、极化细胞迁移和趋化反应过程中的作用和调控。虽然肌球蛋白II是一种关键的和普遍存在的产酶力量，但它在细胞收缩事件中的确切机械作用尚不清楚，而且几乎没有对异构体特定作用的了解。关于肌球蛋白II细丝如何在体内组装和定位，存在多种相互矛盾的模型，并且没有一个流行的模型在体内进行过测试。我们将使用GFP-myosin II报告蛋白的体内成像、光漂白后荧光恢复(FRAP)技术以及siRNA和其他方法来产生对myosin II调节的基本机制的重要新理解，以及对myosin MA和MB在胞质分裂和极化细胞迁移等过程中的异构体特定作用的新理解。我们的研究还将确定在胞质分裂过程中负责激活肌球蛋白II组装和收缩能力的关键上游蛋白激酶和调节蛋白。

DESCRIPTION (provided by applicant): This proposal focuses on deciphering myosin II isoform roles and regulation during cytokinesis and during polarized cell migration and chemotactic responses. Although myosin II is a critical and ubiquitous force producing enzyme, its exact mechanical roles during cellular contractile events is poorly understood, and there is virtually no understanding of isoform specific roles. Multiple conflicting models exist regarding how myosin II filament assembly and localization is regulated in vivo, and none of the prevailing models have been tested in vivo. We will use in vivo imaging of GFP-myosin II reporter proteins, fluorescent recovery after photobleaching (FRAP) technology, as well as siRNA and other approaches to generate significant new understanding of fundamental mechanisms of myosin II regulation and new understanding of the isoform-specific roles of myosin MA and MB in processes such as cytokinesis and polarized cell migration. Our studies will also identify the key upstream protein kinases and regulatory proteins responsible for activation of myosin II assembly and contractility during cytokinesis.