Regulation of cytoplasmic dynein in vivo

项目概要/摘要 我们研究了一种叫做细胞质动力蛋白-1（或简称为“动力蛋白”）的微管马达。在 在真核细胞中，微管充当马达蛋白如动力蛋白和驱动蛋白的轨道， 这些马达蛋白运送货物，包括细胞器，囊泡，蛋白质， mRNA，到不同的细胞位置的功能。微管有两个不同的末端： 端部朝向电池周边，负端靠近电池中心。动力蛋白是一个负端- 定向马达，并且它将货物从单元外围运输到单元中心。除了 包括早期内体和其他细胞器/囊泡在内的生理货物，动力蛋白也 在病毒感染后向内运输病毒颗粒。我们的实验室使用一种丝状真菌， 构巢曲霉作为一个遗传系统，研究如何在活细胞动力蛋白活动， 由其他蛋白质控制。我们和其他科学家发现动力蛋白通过 将驱动蛋白连接到微管正末端，在那里它通过接头与早期内体相互作用 蛋白质如HookA复合物和dynactin复合物。在活细胞中，这些适配器 激活动力蛋白向微管负端移动需要蛋白质。然而，在这方面， 该过程还需要其它蛋白质，例如LIS 1（无脑畸形-1）和VezA（一种vezatin， 如蛋白质）。LIS 1促进动力蛋白的“开放”构象以促进其激活，但是， VezA的作用机制尚不清楚。我们的初步数据还表明，负调节因子是 需要防止动力蛋白过早地离开正端而不携带其 货物，但负面监管机构仍有待确定。此外，还不清楚哪些因素 调节微管负端的货物释放。未来五年，我们将联合收割机 经典遗传学，活细胞成像与全基因组测序，以确定阳性和 动力蛋白活性的负调节剂。我们还将使用活细胞成像，蛋白质组学和 结构分析，以解决VezA和新确定的监管机构的机制。的 曲霉属遗传系统最适合于这些研究。虽然体外实验是 我们的遗传系统非常适合研究已知的蛋白质， 未知的监管机构发现这些调节器将为新的领域铺平道路， 该领域的研究，这将促进进一步的合作， 对动力蛋白发动机复杂调节的机械见解。 .

Project Summary/Abstract We study a microtubule motor called cytoplasmic dynein-1 (or “dynein” for simplicity). In eukaryotic cells, microtubules serve as tracks for motor proteins such as dynein and kinesins to move on. These motor proteins deliver cargoes, including organelles, vesicles, proteins, and mRNAs, to different cellular locations for function. A microtubule has two different ends: the plus end facing cell periphery and the minus end close to the cell center. Dynein is a minus-end- directed motor, and it transports cargoes from the cell periphery toward the cell center. Besides the physiological cargoes including early endosomes and other organelles/vesicles, dynein also transports virus particles inward after viral infection. Our lab uses a filamentous fungus called Aspergillus nidulans as a genetic system to study how dynein activities in live cells are controlled by other proteins. We and other scientists have found that dynein gets transported by a kinesin to the microtubule plus end where it interacts with early endosome via adapter proteins such as the HookA complex and the dynactin complex. In live cells, these adapter proteins are required for activating dynein to move toward the microtubule minus end. However, this process also requires other proteins such as LIS1 (Lissencephaly-1) and VezA (a vezatin- like protein). LIS1 promotes an “open” conformation of dynein to facilitate its activation, but the mechanism of VezA is unclear. Our preliminary data also suggest that negative regulators are needed to prevent dynein from moving away from the plus end prematurely without carrying its cargo, but the negative regulators remain to be identified. Moreover, it is unclear what factors regulate cargo release at the microtubule minus end. In the next five years, we will combine classical genetics, live cell imaging with whole genome sequencing to identify both positive and negative regulators of dynein activities. We will also use live cell imaging, proteomics and structural analysis to solve the mechanisms of VezA and newly identified regulators. The Aspergillus genetic system is best suited for these studies. While in vitro experiments are excellent for studying known proteins, our genetic system has the power for discovering unknown regulators. Discovering these regulators will pave the ways leading to new areas of research in the field, which will stimulate further work involving collaborations to gain mechanistic insights into the intricate regulation of the dynein motor. .