Mechanism of centrosome regulation from the Golgi

描述（由申请人提供）：该项目的目的是了解哺乳动物细胞中邻近高尔基体调节中心体的控制机制。虽然高尔基体和中心体的接近性是哺乳动物细胞所特有的，并且在酵母，植物或苍蝇细胞中没有观察到，但其功能意义一直难以捉摸。我们实验室的工作已经确定了一个中心体调节途径，其中高尔基体蛋白GM130引起鸟嘌呤核苷酸交换因子Tuba激活高尔基体上的Cdc42。该项目旨在确定高尔基体中的这些事件如何控制中心体的组织和功能，以及它们是否依赖于高尔基-中心体的接近程度。

DESCRIPTION (provided by applicant): The objective of this project is to understand a control mechanism that regulates the centrosome from the adjacent Golgi apparatus in mammalian cells. While the proximity of the Golgi and centrosome is unique to mammalian cells, and not observed in yeast, plant or fly cells, its functional significance has been elusive. Work in our laboratory has identified a centrosome regulatory pathway in which a Golgi protein, GM130, causes a guanine nucleotide exchange factor called Tuba to activate Cdc42 at the Golgi. This project seeks to determine how these events at the Golgi control centrosome organization and function and whether they depend on Golgi-centrosome proximity. Aim 1 will determine whether GM130 activates Cdc42 at the Golgi by increasing the binding affinity of Tuba for Cdc42 or by recruiting Cdc42 to the Golgi. This aim will also examine if GM130 is the major regulator of Cdc42 at the Golgi by assaying whether GM130 controls additional cellular processes at the Golgi that are known to be regulated by Cdc42, such as Golgi to ER transport and local actin assembly at the Golgi. A potential negative regulator of Golgi-associated Cdc42 will also be studied. Aim 2 will examine how the GM130-Cdc42 pathway exerts its effect on the centrosome. A Cdc42 effector, Par6?, will be studied to determine if it is a downstream component of this regulatory pathway and if it is transported to the centrosome by the motor protein, dynein, through interactions with the dynactin subunit, p150Glued. PCM-1, a protein that recruits additional proteins to the centrosome, will be studied to determine if it acts downstream of Par6? to mediate the control of centrosome organization by the GM130-Cdc42 pathway. Aim 3 will study the functional significance of Golgi-centrosome proximity by examining if Cdc42 can be mobilized from the Golgi to the centrosome so that it can regulate centrosome organization. The pericentriolar location of the Golgi will be disrupted as another means of testing whether Golgi centrosome proximity is necessary for regulation of centrosome organization by the GM130-Cdc42 pathway.