Mechanisms controlling cell size and shape

项目摘要 在我的实验室，NIGMS资助的研究的总体目标是定义分子和细胞 控制细胞大小和形状的机制。细胞大小和形状的缺陷与 包括癌症在内的人类疾病，因此确定潜在的机制可以确定未来 治疗目标我们使用裂变酵母S。粟酒作为一个模型系统来研究这些 基本过程。这些杆状真核细胞通过线性延伸生长， 极化分泌在生长的细胞尖端，并进入有丝分裂在高度可重复的大小，由于 普遍存在的细胞周期蛋白依赖性激酶Cdk 1的调节激活。几十年的基因筛查 已经确定了用于调节细胞大小和形状的广泛的“部件列表”。我们当前的挑战 将这些部分组装成明确的信号网络，在空间上控制细胞生长， 以大小依赖的方式激活Cdk 1。对于这项工作，我们采取多学科方法 它结合了遗传学、定量活细胞显微镜、磷酸蛋白质组学和生物化学， 重组 在本提案中，我们将解决四个关键的未回答问题。首先，皮质多蛋白 被称为“节点”的簇控制分裂酵母细胞的大小？我们发现节点 含有保守的细胞周期调节因子，包括蛋白激酶Cdr 2、Cdr 1和Wee 1，但 我们不知道节点内的组装或信号转导机制。第二， 是多个细胞周期途径在监测细胞大小方面的作用，例如体积和 表面积？我们将重点关注有丝分裂诱导剂Cdc 25和Cdc 13/cyclin，目标是 生成由数学建模支持的系统级知识。三、如何做细胞 远离生长中的细胞尖端发挥作用的极性机制有助于细胞形状？我们 将利用我们最近的发现，涉及RNA颗粒和SNARE蛋白质簇， 新型的“远距离”细胞极性和形状调节器。四、细胞大小和形状如何 影响细胞中节点的空间模式？我们已经确定了细胞尖端，皮质锚， 细胞核是节点定位的关键调节器。我们将联合收割机基因突变体与 定量荧光显微镜和基于粒子的模拟，以确定潜在的 本系统的设计原则。基于对这些途径的广泛保护， 酵母和哺乳动物之间的过程，我们完全期望我们的工作发现将影响 并指导其他生物体和生物系统的未来工作。

PROJECT SUMMARY The overall goal of NIGMS-funded research in my lab is to define the molecular and cellular mechanisms that control cell size and shape. Defects in cell size and shape are associated with human diseases including cancer, so defining the underlying mechanisms can identify future therapeutic targets. We use the fission yeast S. pombe as a model system to study these fundamental processes. These rod-shaped eukaryotic cells grow by linear extension due to polarized secretion at growing cell tips, and enter mitosis at a highly reproducible size due to regulated activation of the ubiquitous cyclin-dependent kinase Cdk1. Decades of genetic screens have identified an extensive “parts list” for regulation of cell size and shape. Our current challenge is to assemble these parts into defined signaling networks that spatially control cell growth and activate Cdk1 in a size-dependent manner. For this work, we take a multidisciplinary approach that combines genetics, quantitative live-cell microscopy, phosphoproteomics, and biochemical reconstitution. In this proposal, we will address four key unanswered questions. First, how do cortical multiprotein clusters called “nodes” control fission yeast cell size at division? We discovered that nodes contain conserved cell cycle regulators including the protein kinases Cdr2, Cdr1, and Wee1, but we do not know the mechanisms of assembly or signal transduction within nodes. Second, what is the role of multiple cell cycle pathways in monitoring aspects of cell size such as volume and surface area? We will focus on the mitotic inducers Cdc25 and Cdc13/cyclin, with the goal of generating systems-level knowledge supported by mathematical modeling. Third, how do cell polarity mechanisms that function far away from the growing cell tips contribute to cell shape? We will exploit our recent discoveries that implicate RNA granules and SNARE protein clusters as novel “at-a-distance” regulators of cell polarity and shape. Fourth, how do cell size and shape influence spatial patterning of nodes in cells? We have identified cell tips, cortical anchors, and the nucleus as critical regulators of node positioning. We will combine genetic mutants with quantitative fluorescence microscopy and particle-based simulations to define the underlying design principles of this system. Based on extensive conservation of these pathways and processes between yeast and mammals, we fully expect that discoveries from our work will impact and guide future work in other organisms and biological systems.