P107 FUNCTION IN 3T3-L1 DIFFERENTIATION

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 肥胖是困扰我们社会的许多主要慢性疾病的风险因素，包括冠状动脉疾病、糖尿病和癌症。了解成脂干细胞控制细胞周期退出和启动终末分化的详细分子机制，将为合理设计治疗方法打开大门，补充现有治疗方法以减轻肥胖及其副作用。 3T3L1细胞是研究较多的脂肪细胞分化模型系统。静止的3T3L1细胞高水平表达Rb相关蛋白p130，但几乎不表达p107。在刺激分化后的24小时内，p107的表达达到高水平，而p130的表达下降。随着细胞完成分化，p107和p130恢复到原来的水平。蛋白激酶抑制剂的数据表明，p107的快速诱导对分化至关重要，但对增殖并不是必需的。我们假设Pocket蛋白pRb、p107和p130通过与调控蛋白的相互作用在脂肪细胞的细胞周期退出和分化中发挥关键作用，从而刺激或抑制这些调控蛋白的活性，启动一系列事件，导致细胞增殖能力的永久性变化。 我们计划鉴定p107在3T3L1细胞终末分化早期的蛋白-蛋白相互作用，并确定哪些蛋白-蛋白相互作用对前脂肪细胞细胞周期退出和终末分化起关键作用。这些络合物的组成将通过质谱学进行鉴定。这些成分将作为干扰的靶点，以确定它们在3T3L1细胞分化中的作用。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Obesity is a risk factor in many of the major chronic diseases that afflict our society, including coronary artery disease, diabetes mellitus, and cancer. Understanding the detailed molecular mechanisms involved in the control of cell cycle exit and initiation of terminal differentiation in adipogenic stem cells will open the door to rationally designed treatments that complement existing treatments to alleviate obesity and its side effects. 3T3L1 cells are a well-studied model system for the differentiation of adipocytes. Quiescent 3T3L1 cells express high levels of the Rb-related protein p130 but little if any p107. Over the first 24 hours after they are stimulated to differentiate, the expression of p107 increases to a high level while that of p130 drops. p107 and p130 return to their former levels as the cells complete differentiation. Data with protein kinase inhibitors suggest that the rapid induction of p107 is critical for differentiation but not necessary for proliferation. We hypothesize that the pocket proteins pRB, p107, and p130 carry out their critical roles in adipocyte cell cycle withdrawal and differentiation through their interactions with regulatory proteins, by which they stimulate or inhibit the activity of these regulatory proteins, setting in motion a chain of events that results in a permanent change in the ability of cells to proliferate. We plan to identify the protein-protein interaction of p107 during the early stages of terminal differentiation of 3T3L1 cells and determine which of the protein-protein interaction are critical for preadipocyte cell cycle withdrawal and terminal differentiation. The components of these complexes will be identified by mass spectrometry. These components will be targeted for disruption to determine their role in the differentiation of 3T3L1 cells.