Proliferation-quiescence control by integration of stress and mitogen signaling

描述（由申请人提供）：在几乎所有类型的癌症中，进入细胞周期是不受控制的，这表明细胞决定增殖或保持静止的重要性。尽管如此，参与细胞进行另一轮细胞分裂的分子事件还没有很好地定义。这个建议的总体目标是建立一个定量的、动态的和机制的理解增殖-静止的决定在正常的体细胞。具体来说，我对细胞如何在前一个细胞周期结束时整合应激和生长因子信号输入来控制有丝分裂后的增殖或静止状态感兴趣。实现这一目标的关键是我在分子水平上监测单个异步循环细胞的细胞周期事件的能力。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。细胞周期的特征是CDK2活性的增加，而静止细胞缺乏CDK2活性。我的第一个目标是确定CDK抑制剂p21如何控制有丝分裂后，细胞是否立即建立CDK2活性并选择增殖命运或关闭CDK2活性并选择静止命运。我的第二个目标将探索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恢复循环，以及一个细胞周期中的DNA损伤如何影响下一个周期中的增殖静止决定。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在前一个细胞周期的G2/M中整合以影响细胞的增殖或静止命运。我将上游信号转导事件与单细胞增殖静止结果联系起来的能力将为这一关键控制点提供有价值的见解，并可能确定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.