Proliferation-quiescence control by integration of stress and mitogen signaling

描述(申请人提供)：进入细胞周期几乎所有类型的癌症都被解除管制，证明了细胞决定是增殖还是保持静止的重要性。尽管如此，细胞承诺进行另一轮细胞分裂所涉及的分子事件还没有得到很好的定义。这项建议的总体目标是对正常体细胞的增殖-静止决定建立一个定量的、动态的和机械的理解。具体地说，我感兴趣的是细胞如何在前一个细胞周期结束时整合压力和生长因子信号输入，以控制有丝分裂后增殖或静止的FAE。实现这一目标的关键是我有能力在分子水平上监测单个异步周期细胞的细胞周期事件。我将利用我开发的一种新的活细胞传感器来监测细胞周期蛋白依赖性激酶2(CDK2)的活性，这是细胞周期进程的关键驱动因素。细胞周期承诺的标志是CDK2活性的增强，而静止的细胞缺乏CDK2活性。我的第一个目标将是确定CDK抑制剂p21如何控制细胞在有丝分裂后是立即增强CDK2活性并选择增殖命运，还是关闭CDK2活性并选择静止命运。我的第二个目标是探索DNA损伤导致细胞周期停滞的动力学，细胞如何从这种损伤中恢复并重新开始循环，以及一个细胞周期中的DNA损伤如何影响下一个周期的增殖停滞决定。在我的第三个目标中，我试图了解生长因子信号如何调节细胞周期机制以驱动增殖，以及有丝分裂信号如何整合到前一个细胞周期的G2/M期以影响细胞增殖或静止的命运。我能够将上游信号转导事件与单细胞的增殖抑制结果联系起来，这将为了解这一关键控制点提供有价值的见解，并可能识别用于治疗癌症的新靶点。

DESCRIPTION (provided by applicant): Entry into the cell cycle is deregulated in nearly all types of cancer, demonstrating the importance of the cellular decision to proliferate or remain quiescent. Despite this, the molecular events involved in a cell's committing to another round of cell division are not well defined. The overall goal of this proposal is to build a quantitative, dynamic, and mechanistic understanding of the proliferation-quiescence decision in normal, somatic cells. Specifically, I am interested in how cells integrate stress and growth factor signaling inputs at the end of the previous cell cycle to control the proliferative or quiescent fae after mitosis. Key to achieving this goal is my ability to monitor cell cycle events at the moleculr level in single, asynchronously cycling cells. I will make use of a new live-cell sensor that I developed that monitors Cyclin-dependent kinase 2 (CDK2) activity, a key driver of cell cycle progression. Cell cycle commitment is marked by a buildup of CDK2 activity, whereas quiescent cells lack CDK2 activity. My first aim will be to determine how the CDK inhibitor, p21, controls whether, after mitosis, cells immediately build up CDK2 activity and choose a proliferative fate or turn CDK2 activity off and choose a quiescent fate. My second aim will explore the dynamics with which DNA damage causes cell cycle arrest, how cells recover from this damage and resume cycling, and how DNA damage in one cell cycle affects the proliferation-quiescence decision in the next cycle. In my third aim, I seek to understand how growth factor signaling regulates the cell cycle machinery to drive proliferation and how mitogenic signals are integrated in G2/M of the previous cell cycle to influence the proliferative or quiescent fate of a cell. My ability to link upstream signal transduction events to the proliferation-quiescence outcome in single cells will provide valuable insight into this critical control point and may identify new targets that be exploited therapeutically for treating cancer.