Mechanisms for the Termination of Myosin V-Mediated Transport

项目摘要/摘要： 细胞内细胞器的组织是正常细胞功能和动物功能的关键因素。 生理学。许多途径有助于细胞器的本地化；分子马达就是一个例子 将货物运送到指定的位置以确定细胞的极性。本提案重点关注肌球蛋白V 摩托公司。肌球蛋白V发动机的缺陷导致货物定位错误，这是几种疾病的基础 包括皮肤色素障碍、肠道疾病和神经疾病。肌球蛋白V的调节作用 货物运输在一定程度上是通过调节货物特有的适配蛋白发生的。这项提案的重点是 酵母液泡/溶酶体，与细胞周期协调遗传。在细胞周期的早期， 肌球蛋白V马达Myo2通过液泡特有的适配器Vac17与液泡相连。此附件是 部分受细胞周期蛋白依赖性激酶CDK1的调节。值得注意的是，脱离Myo2也是高度 控制，表明复杂的机械装置发出信号，货物已到达正确的位置。 从液泡中释放MyO2需要E3泛素连接酶Dma1，该酶被招募到害虫中 Vac17上的序列。此外，Dma1对过氧化物体的释放也是必不可少的，这表明 Dma1在终止Myo2介导的货物运输中的保守作用。我们的初步研究表明 需要一个额外的步骤来促进依赖Dma1的Vac17的泛素化。我们直接发现了Cla4 磷酸化Vac17-S222，并且这种磷酸化事件对于液泡的释放是重要的 芽尖，Vac17的泛素化，最终Vac17的周转。此外，抑制对Cla4的依赖 Va17的磷酸化导致Vac17在芽尖积累，表明Cla4作为一种 时空调节，启动液泡运输的终止。我的中心假设是 是发出肌球蛋白V到达目的地的信号的机制，这反过来又调节 它的货物。在这项提案中，我的目标是确定依赖Cla4的下游后果 Vac17的磷酸化。这些研究将阐明以汽车为基础的货物运输的监管机制。 并对肌球蛋白V介导的货物运输受损引起的疾病提供更深入的了解。

Project Summary/Abstract: The organization of organelles within cells is a critical factor in normal cellular function as well as animal physiology. Many pathways contribute to the localization of organelles; one example is molecular motors that transport cargoes to a designated location to establish cellular polarity. This proposal focuses on myosin V motors. Defects in myosin V motors cause mislocalization of cargoes, which underlies several diseases including skin pigment disorders, gut diseases, and neurological disorders. The regulation of myosin V based cargo transport occurs in part via the regulation of cargo-specific adaptor proteins. This proposal focuses on the yeast vacuole/lysosome, which is inherited in coordination with the cell cycle. Early in the cell cycle, the myosin V motor, Myo2, attaches to the vacuole via the vacuole specific adaptor, Vac17. This attachment is regulated in part by the cyclin dependent kinase Cdk1. Notably, detachment from Myo2 is also highly controlled, indicating that complex mechanisms signal that the cargo has arrived at the correct location. Release of Myo2 from the vacuole requires an E3 ubiquitin ligase, Dma1, which is recruited to the PEST sequence on Vac17. Moreover, Dma1 is also essential for the release of peroxisomes, suggesting a conserved role for Dma1 in terminating Myo2 mediated cargo transport. Our preliminary studies suggest that an additional step is required to facilitate Dma1 dependent ubiquitylation of Vac17. We found that Cla4 directly phosphorylates Vac17-S222, and that this phosphorylation event is important for release of the vacuole from the bud tip, ubiquitylation of Vac17, and ultimately Vac17 turnover. Additionally, inhibiting Cla4-dependent phosphorylation of Va17 results in the accumulation of Vac17 at the bud tip, suggesting that Cla4 acts as a spatiotemporal regulator and initiates the termination of vacuole transport. My central hypothesis is that there are mechanisms that signal that myosin V has arrived at its destination, which in turn regulates the release of its cargoes. In this proposal, I aim to determine the downstream consequences of Cla4-dependent phosphorylation of Vac17. These studies will elucidate mechanisms that regulate motor-based cargo delivery and provide greater insight into diseases caused by impaired myosin V mediated cargo transport.