Signaling Pathways and Microtubule Function

描述(申请人提供)：我们的长期目标是了解细胞中的信号通路如何控制微管的属性。具体地说，我们将集中在蛋白激酶C(PKC)介导的丝裂原活化蛋白激酶(MAPK)和CDC42pICdc24P通路在控制微管稳定性方面可能发挥的作用。我们的工作假设建立在初步研究的基础上，在这些研究中，我们确定了参与这些途径的两个基因是后期马达蛋白Cin8和Dy1突变的多拷贝抑制基因。这些基因分别是KRE6，据报道抑制pkc1的裂解表型，酵母PKC同源物，以及GIC1，CDC42p的效应者。在其他初步实验中，我们发现这些抑制物可能通过稳定微管发挥作用。我们的具体目标将是(1)寻找与这些通路相关的其他抑制因子，(2)表征抑制因子对微管功能的影响，以及(3)研究微管功能与上述通路的关系。对于目标1，我们将继续研究我们之前分离的抑制子克隆。在目标2中，我们将研究在抑制因子的作用下细胞质和核微管的组织和功能。在目标3中，我们将使用遗传学方法来研究与上述途径相关的基因突变和过度表达对微管特性的影响。该项目取得的成果将在两个方面提供新的重要信息。首先，他们将展示调节极化生长和各种皮质事件的保守信号机制如何影响微管依赖的过程。其次，他们将展示这些途径是如何相互作用的。

DESCRIPTION (provided by applicant): Our long-term goal is to understand how signaling pathways in the cell control properties of microtubules. Specifically, we will concentrate on possible roles of the protein kinase C (PKC)-mediated mitogen activated protein kinase (MAPK) and the Cdc42pICdc24p pathways in controlling microtubule stability. Our working hypothesis is based on preliminary studies in which we identified two genes involved in these pathways as multicopy suppressors of mutations in the anaphase motor proteins Cin8 and Dyn1. The genes are KRE6 that was reported to suppress the lysis phenotype of pkc1, the yeast PKC homolog, and GIC1, an effector of Cdc42p. In other preliminary experiments, we found that these suppressors may act by stabilizing microtubules. Our specific aims will be (1) to identify additional suppressors related to these pathways, (2) to characterize the effect of the suppressors on microtubule function, and (3) to study the relation between microtubule function and the above pathways. For aim 1 we will continue to investigate suppressor clones that we previously isolated. In aim 2 we will study organization and function of cytoplasmic and nuclear microtubules under the effect of the suppressors. In aim 3 we will use a genetic approach to investigate the effect of mutations in, and overexpression of, genes related to the above pathways on microtubule properties. Results obtained in this project will provide new and important information in two contexts. First, they will show how conserved signaling mechanisms that regulate polarized growth and a variety of cortical events affect microtubule--dependent processes. Second, they will show how these pathways interact.