Microtubule dynamics and cellular pattern formation

描述（由申请人提供）：微管细胞骨架对细胞过程至关重要，如有丝分裂、细胞器运输和细胞极性。微管的关键组织者是微管组织中心（MTOC）。所有MTOCs都由多蛋白复合物组成，并具有三个一般特性：a)它们具有微管核。b)它们将微管排列成功能模式。c)它们将微管附着在合适的细胞器目标上。近年来，人们对动物细胞中主要的MTOC——中心体上的分子进行了分类，并在理解位于中心体核微管的g-微管蛋白环复合物（g-TuRC）的机制方面取得了很大进展。然而，大多数细胞质g- turc并不位于中心体，其细胞功能尚不清楚。此外，虽然典型中心体排列的微管呈放射状排列并附着在细胞核上，但许多高度分化的细胞类型——神经元、肌管和极化上皮细胞——具有不附着在细胞核上的微管线性排列。产生微管线性阵列的机制是未知的，是本研究计划的主题。我的实验室最近发现了ase1+和mto2+，它们的基因产物定位于三种不同的MTOCs。Ase1p在微管的线性排列中起关键作用；mto2p在微管成核中起关键作用。现在我们将重点剖析ase1p和mto2p在组织微管线性阵列中的作用。本课题将结合酵母遗传学、生物化学和分子生物学，结合FRAP和光镊等定量光学显微镜方法，研究ase1p和mto2p在线性微管阵列组织中的作用。我们的研究将为线性微管阵列生物发生的分子机制提供新的见解。此外，进化保守性将使我们在裂变酵母中的发现与我们对人类细胞中类似保守结构的理解高度相关，并可能有助于我们对MTOC形成和功能病理引起的疾病的理解。

DESCRIPTION (provided by applicant): The microtubule cytoskeleton is essential for cellular processes such as mitosis, organelle transport, and cell polarity. The key organizer of microtubules is the microtubule organizing center (MTOC). All MTOCs are composed of multi-protein complexes and share three general properties: a) They nucleate microtubules. b) They arrange the microtubules into functional patterns. And c) They attach the microtubules to their proper organelle targets. In recent years the molecules that are localized to the centrosome, the primary MTOC in animal cells, have been catalogued and much progress has been made in understanding the mechanism by which the g-tubulin ring complex (g-TuRC) located at the centrosome nucleate microtubules. However, most cytoplasmic g-TuRCs are not located at the centrosome, and their cellular functions are unknown. Furthermore, while the canonical centrosome arranges radial arrays of microtubules which are attached to the nucleus, many highly differentiated cell types - neurons, myotubes, and polarized epithelial cells - have linear arrays of microtubules which are not attached to the nucleus. The mechanisms which generate linear arrays of microtubules are unknown and is the subject of this research proposal. My lab recently identified ase1+ and mto2+, whose gene products localize to the three different MTOCs. Ase1p plays key roles in linear arrangement of microtubules; and mto2p plays key roles in microtubule nucleation. And we will now focus on dissecting the roles of ase1p and mto2p in organizing linear arrays of microtubules. This proposal will combine yeast genetics, biochemistry, and molecular biology with quantitative optical microscopy methods such as FRAP and optical tweezers to study the role of ase1p and mto2p in organizing linear microtubule arrays. Our studies will provide new insights into the molecular mechanism which underlie the biogenesis of linear microtubule arrays. Furthermore, evolutionary conservation will make our findings in fission yeast highly relevant to our understanding of similar conserved structures in human cells, and may contribute to our understanding of disease arising from the pathology of MTOC formation and function.