MOLECULAR ANALYSIS OF THE YEAST ACTIN CYTOSKELETON

描述：在酵母细胞周期中，肌动蛋白的分布发生变化。 以一种非常具体的方式反映了增长本地化的变化 在这段时间内发生的事情。然而，鲜为人知的是， 肌动蛋白定位和生长的改变是受调节或调节的。 肌动蛋白结合蛋白可能是重要的，因为缺乏这些的突变体 蛋白质在这些过程中是有缺陷的。然而，尽管事实是 这些蛋白质中的许多都有很好的生化特征，但很少有 已知各种肌动蛋白结合蛋白的活性是如何在 体外影响肌动蛋白在体内的组织和生长。私家侦探正专注于 肌动蛋白-细丝交联蛋白Fimbrin(Sac6)，这是唯一的 肌动蛋白--酵母中已知的细丝交联蛋白。肌动蛋白的交联 细丝可能对肌动蛋白的许多功能是必不可少的，如 单个细丝不能承受很强的压缩力。 然而，人们对交联剂的调节作用知之甚少。 在酵母或其他细胞中。在这笔拨款中，私家侦探建议确定 Sac6对肌动蛋白-细丝交叉连接的作用和可能的调节。 特别是，私家侦探将首先检查分子结构 肌动蛋白-细丝交联剂。私家侦探会问这两个肌动蛋白 Sac6的结合域与肌动蛋白上相同或不同的位点结合。 其次，私家侦探将确定Sac6是否受到监管或在 细胞周期的特定阶段。第三，私家侦探将使用基因筛查 确定揭示Sac6调控或作用的蛋白质。 手机。这些筛选将涉及到寻找对杀伤力的抑制 由Sac6的过度表达或Sac6-19突变体的表达引起， 使肌动蛋白格外紧密地结合在一起。

DESCRIPTION: During the yeast cell cycle, the distribution of actin changes in a highly specific way that reflects the changes in localization of growth that occur during this time. However, little is known of how the alterations in actin localization and growth are mediated or regulated. Actin-binding proteins are likely important, as mutants lacking these proteins are defective in these processes. However, despite the fact that many of these proteins have been well characterized biochemically, little is known of how the the activities of the various actin-biinding proteins in vitro affect actin organization and growth in vivo. The P.I. is focusing on the actin-filament cross-linking protein fimbrin (Sac6), which is the only actin-filament cross-linking protein known in yeast. Cross-linking of actin filaments is likely essential for many of the functions of actin, as individual filaments are unable to withstand strong compressional forces. However, little is known of either the roles of regulation of cross-linking in yeast or in other cells. In this grant, the P.I. proposes to identify the roles and possible regulation of actin-filament corss-linking by Sac6. In particular, the P.I. will first examine the molecular architecture of actin-filament cross-linking. The P.I. will ask whether the two actin binding domains of Sac6 bind to the same or different sites on actin. Second, the P.I. will determine whether Sac6 is regulated or has roles at specific stages of the cell cycle. Third, the P.I. will use genetic screens to identify proteins that reveal the regulation or roles of Sac6 in the cell. These screen will involve looking for suppression of the lethality caused by over-expression of Sac6, or expression of the Sac6-19 mutant, which binds actin extra-tightly.