CELLULAR FUNCTION OF ACTIN HOMOLOGUES

Centractins代表高度保守的哺乳动物基因家族，其 序列表明与肌动蛋白有显著的相似性(&gt；70%)。 这个家族的成员已经定位于着丝粒和大的 泡状结构的形态分析。此外，生化方面 研究表明，中央肌动蛋白与20多岁的胞浆有关 蛋白质颗粒称为P150(胶状)，或动力蛋白复合体。这 复合体与细胞质动力蛋白的功能有关， 负责囊泡逆行运输的分子马达 沿着微管。因为至少有两种异构体的中央肌动蛋白 以及一种与酵母肌动蛋白相关的新基因 蛋白(ARP)，可能代表中央肌动蛋白的功能同源物。 这里描述的研究的目的是使用生化， 形态和遗传技术回答了最基本的问题 与中央肌动蛋白在细胞功能中的作用有关的问题。这些 包括：由于中央肌动蛋白异构体具有单独的亚细胞定位， 它们在功能上有何不同？中央肌动蛋白是否能够聚合 形成多聚体复合体或细丝，以与肌动蛋白同源的方式， 或者作为肌动蛋白结合蛋白？什么是“中枢肌动蛋白表型”？ 在其中央肌动蛋白表达或完整性已经被 妥协？酵母菌ARP，Act3，是 中央肌动蛋白，如果是这样的话，它在这个有机体中扮演什么角色？

Centractins represent a family of highly-conserved mammalian genes whose sequences indicate a significant degree of similarity (>70%) to actin. Members of this family have been localized to centrosomes and large vesicular structures by morphological analyses. In addition, biochemical studies have shown that centractins are associated with a 20S cytosolic proteinaceous particle known as the p150(Glued), or dynactin complex. This complex has been implicated in the function of cytoplasmic dynein, a molecular motor which is responsible for retrograde vesicular transport along microtubules. As at least two isoforms of centractin have been characterized in our laboratory, as well as a novel yeast actin-related protein (ARP) which may represent a functional homologue of centractin. It is the aim of the research described here to use biochemical, morphological and genetic techniques to answer the most fundamental questions pertinent to the role of centractins in cellular function. These include: As centractin isoforms have individual subcellular localizations, how do they differ functionally? Are centractins capable of polymerizing into multimeric complexes or filaments, in a fashion homologous to actin, or to serve as actin-binding proteins? What is the "centractin phenotype" in mammalian cells whose centractin expression or integrity has been compromised? Is the yeast ARP, ACT3, the functional homologue of centractin, and if so what is its role in this organism?