Regulation of Myosin Function by Protein Kinases and Light Chains

蛋白激酶和轻链对肌球蛋白功能的调节

• 批准号: RGPIN-2016-04666
• 负责人: Cote, Graham
• 金额: $ 2.26万
• 依托单位: Queen's University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=615224
• 关键词: Regulation; Myosin; Function; Protein; Kinases

Cells crawl over surfaces, extend and retract surface protrusions, change shape, engulf other organisms, take up liquid nutrients and divide by splitting into two. These varied forms of cell movement are driven by myosin, a remarkable molecular motor that converts chemical energy into a force that is used to travel along, or pull on, actin filaments. Our research focuses on two ubiquitous classes of myosin: myosin-I and myosin-II. Myosin-I links cell membranes to actin filaments and is involved driving membrane shape changes. Myosin-II, also called muscle myosin, assembles into bipolar filaments that contract networks of actin filaments. We are investigating three mechanisms that regulate myosin-I and myosin-II activity. These regulatory processes are critical to ensure that movement or force generation occurs in the cell only where and when it is required. Our first research project involves a protein kinase, termed MHCK-A, that blocks the assembly of myosin-II into filaments. Interestingly, MHCK-A has a novel type of protein kinase domain and is the founding member of a family of atypical protein kinases termed the alpha-kinases. We have shown that the structure and catalytic properties of MHCK-A differ considerably from those of conventional protein kinase. We will further study the structure, catalytic and regulatory properties of MHCK-A in order to shed new light on this poorly understood but important kinase family. Our second project concerns two novel light chains, MlcB and MlcC, that we discovered as components of myosin-I. Myosin light chains, which stabilize and regulate the myosin motor domain, are normally 16 kDa in size, but MlcB and MlcC are only 8-kDa in size. We will examine how MlcB and MlcC bind to, stabilize and regulate myosin-I activity, and will also investigate the possibility that they bind to other proteins. Our third project involves a protein kinase, PakB, that activates myosin-I. We will pursue an intriguing observation that we have made which indicates that PakB plays a critical role in regulating the ability of myosin-I to link the plasma membrane to the underlying actin filament network. Our findings will advance the basic knowledge of how myosin-dependent cell motility is regulated. It will provide valuable information that can be employed to generate specific inhibitors to block motile processes, which could be useful for diseases such as cancer metastases or inflammation in which cell migration plays a central role. HQP will develop a diverse and comprehensive research skill set with expertise in molecular biology, structural biology, enzymology and cell biology.

细胞在表面爬行，伸展和缩回表面突起，改变形状，吞噬其他生物体，吸收液体营养物质并分裂成两部分。这些不同形式的细胞运动由肌球蛋白驱动，肌球蛋白是一种非凡的分子马达，可将化学能转化为沿着肌动蛋白丝移动或拉动的力。我们的研究重点是两类普遍存在的肌球蛋白：肌球蛋白-I 和肌球蛋白-II。肌球蛋白-I 将细胞膜与肌动蛋白丝连接起来，并参与驱动膜形状的变化。肌球蛋白-II，也称为肌肉肌球蛋白，组装成双极丝，收缩肌动蛋白丝网络。我们正在研究调节肌球蛋白-I 和肌球蛋白-II 活性的三种机制。这些调节过程对于确保细胞中仅在需要的地方和时间发生运动或力的产生至关重要。我们的第一个研究项目涉及一种名为 MHCK-A 的蛋白激酶，它可以阻止肌球蛋白-II 组装成细丝。有趣的是，MHCK-A 具有一种新型蛋白激酶结构域，并且是称为 α 激酶的非典型蛋白激酶家族的创始成员。我们已经证明 MHCK-A 的结构和催化特性与传统蛋白激酶有很大不同。我们将进一步研究 MHCK-A 的结构、催化和调节特性，以便为这个人们知之甚少但重要的激酶家族提供新的线索。我们的第二个项目涉及两种新型轻链 MlcB 和 MlcC，我们发现它们是肌球蛋白-I 的组成部分。肌球蛋白轻链负责稳定和调节肌球蛋白运动结构域，其大小通常为 16 kDa，但 MlcB 和 MlcC 的大小仅为 8 kDa。我们将研究 MlcB 和 MlcC 如何结合、稳定和调节肌球蛋白-I 活性，还将研究它们与其他蛋白质结合的可能性。我们的第三个项目涉及一种蛋白激酶 PakB，它可以激活肌球蛋白-I。我们将继续进行一项有趣的观察，该观察表明 PakB 在调节肌球蛋白-I 连接质膜与​​底层肌动蛋白丝网络的能力方面发挥着关键作用。我们的研究结果将增进有关肌球蛋白依赖性细胞运动如何调节的基础知识。它将提供有价值的信息，可用于生成特定的抑制剂来阻断运动过程，这可能对癌症转移或炎症等细胞迁移起核心作用的疾病有用。 HQP 将开发多样化、全面的研究技能，涵盖分子生物学、结构生物学、酶学和细胞生物学方面的专业知识。