Nuclear Accumulation of Cyclin D1 and Oncogenesis

描述(由申请人提供)：我们的长期目标是确定 细胞周期机器如何感知细胞外信号，然后 传递到受调控的细胞周期进程中。这样做的具体目的是 建议是定义位点特异性磷酸化在 调控细胞周期蛋白D1的核进出口，以确定 细胞周期蛋白D1的定位与蛋白降解的关系 构成核的细胞周期蛋白D1的潜在致癌性， 并探讨细胞周期蛋白D1依赖的转化机制。 种间异核体分析将被用来检查 调控细胞周期蛋白D1核出口，并将在体外进行核进口检测 用于直接确定细胞周期蛋白D1的核输入机制(S)。这个 对于有效的Cyclin DL蛋白分解来说，核出口的必要性也将是 使用体外和体内技术测定。最后，我们将测试 S期未能将细胞周期蛋白D1从细胞核中移除的假说 对正常的细胞增殖至关重要，因为它创造了携带 细胞周期蛋白D1变异体，D1-T286A，其表达受 免疫球蛋白内含子增强子元件，E(Mu)。对正常生长的颠覆 信号通路是肿瘤形成的一个标志，而细胞周期蛋白D1的能力 作为有丝分裂传感器，将生长因子信号整合到细胞周期中 进展使其经常成为癌症的靶子。建议的研究将 确定决定细胞周期蛋白D1亚细胞的调控机制 定位，确定定位在细胞周期蛋白D1积累中的作用，以及 演示细胞如何限制细胞周期蛋白D1的活性，从而阻止 肿瘤。

DESCRIPTION (PROVIDED BY APPLICANT): Our long-term objective is to determine how extra-cellular signals are sensed by the cell cycle machine and then transmitted into regulated cell cycle progression. The specific aims of this proposal are to define the role o the site-specific phosphorylation in the regulation of cyclin D1 nuclear import and export, to determine the relationship between cyclin D1 localization and the proteolysis, to explore the potential oncogenicity of cyclin D1 proteins that are constitutively nuclear, and to determine the mechanism of cyclin D1-dependent transformation. Interspecies heterokaryon assays will be used to examine the parameters that regulate cyclin D1 nuclear export, and in vitro nuclear import assays will be used to directly determine the mechanism(s) of cyclin D1 nuclear import. The necessity of nuclear export for efficient cyclin Dl proteolysis will also be determined using both in vitro and in vivo techniques. Finally, we will test the hypothesis that failure to remove cyclin Dl from the nucleus during S-phase is critical for normal cellular proliferation by creating mice carrying the cyclin D1 variant, D 1-T286A, whose expression is controlled by the immunoglobulin intron enhancer element, E(mu). The subversion of normal growth signaling pathways is a hallmark of neoplasia, and the capacity of cyclin D1 to act as a mitogenic sensor that integrates growth factor signals into cell cycle progression makes it a frequent target in Cancer. The studies proposed will identify the regulatory mechanisms that determine cyclin D1 subcellular localization, determine the role of localization in cyclin D1 accumulation, and demonstrate how cells constrain cyclin D1 activity, thereby preventing neoplasia.