Myosin II Dynamics and Assembly in Mammalian Cells

描述（由申请方提供）：该提案重点在于解读胞质分裂期间以及极化细胞迁移和趋化反应期间肌球蛋白II亚型的作用和调控。虽然肌球蛋白II是一个关键的和普遍存在的力产生酶，其确切的机械作用在细胞收缩事件是知之甚少，几乎没有了解亚型的具体作用。关于肌球蛋白II细丝组装和定位如何在体内调节存在多种相互冲突的模型，并且没有一种流行的模型在体内进行了测试。我们将使用GFP-肌球蛋白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，以产生显着的肌球蛋白II调节的基本机制的新认识和肌球蛋白MA和MB在胞质分裂和极化细胞迁移等过程中的亚型特异性作用的新认识。我们的研究还将确定关键的上游蛋白激酶和调节蛋白，负责激活肌球蛋白II组装和细胞质分裂过程中的收缩。

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.