Regulation of Cellular Survival, Size and Metabolism

描述（由申请人提供）： 癌症的发展是由于不受控制的细胞增殖加上程序性细胞死亡诱导缺陷的结果。 已经显示出防止细胞死亡的两类基因是促存活Bcl-2家族成员和丝氨酸-苏氨酸激酶Akt。 先前关于Akt的工作已经证明，以Akt依赖性方式存活的细胞的特征在于增加的细胞大小和对增加的细胞代谢的依赖。 Akt控制细胞大小和代谢的分子机制尚不清楚。 结节性硬化症基因TSC 2是Akt的潜在底物，并且已经显示当与其结合伴侣TSC 1一起表达时调节细胞大小。 在该提案中，将进行实验以确定Akt依赖性增加细胞大小、代谢和存活的分子靶点。 将评估错构蛋白和块茎蛋白的表达对这些相同过程的影响，以及TSC 2是Akt底物的可能性。 具体目标： 1.确定Akt控制细胞大小和存活的主要下游靶点。 A.确定通过Akt活化在造血细胞中诱导的主要磷蛋白。 B。确定Akt β信号的主要下游靶点中的哪一个在没有生长因子的情况下维持细胞活力、代谢和大小。 C.表征Akt诱导的底物降解。 2.检测结节性硬化症基因在调节造血细胞大小和存活中的作用。 A.表征生长因子停药后造血细胞中TSC 1和TSC 2表达的变化。 B。在对照、表达Bcl-xL和活化Akt的细胞中表达TSC 1和TSC 2，并在存在和不存在生长因子的情况下测量细胞周期、大小、活力和代谢的变化。 C.确定TSC 1和TSC 2是否有助于Akt对细胞大小或存活的影响。 测试潜在的Akt磷酸化位点在块茎蛋白中的重要性。 总之，这些研究将有助于确定原癌基因Akt和肿瘤抑制基因TSC 1和TSC 2在与这些基因相关的癌症中细胞代谢失调中的作用。

DESCRIPTION (provided by applicant): Cancer develops as a result of uncontrolled cell proliferation coupled with defects in the induction of programmed cell death. Two classes of genes that have been shown to prevent cell death are the pro-survival Bcl-2 family members, and the serine-threonine kinase Akt. Previous work with Akt has demonstrated that cells surviving in an Akt-dependent manner are characterized by increased cell size and a reliance on increased cell metabolism. The molecular mechanisms by which Akt controls cell size and metabolism are unclear. The tuberous sclerosis gene TSC2 is a potential substrate of Akt, and has been shown to regulate cell size when expressed together with its binding partner, TSC1. In this proposal, experiments will be performed to determine the molecular targets for Akt-dependent increases in cell size, metabolism, and survival. The effects of the expression of hamartin and tuberin on these same processes will be assessed, as well as the possibility that TSC2 is an Akt substrate. Specific aims: 1. Identify the major downstream targets of Akt in the control of cell size and survival. A. Determine the major phosphoproteins induced in hematopoietic cells by activation of Akt. B. Determine which of the major downstream targets of Akt transduce signals that maintain cellular viability, metabolism and size in the absence of growth factor. C. Characterize Akt-induced degradation of its substrates. 2. Test the role of the tuberous sclerosis genes in regulating cell size and survival in hematopoietic cells. A. Characterize changes in TSC1 and TSC2 expression in hematopoietic cells upon growth factor withdrawal. B. Express TSC1 and TSC2 in control, Bcl-xL- and activated Akt-expressing cells, and measure changes in cell cycle, size, viability and metabolism in the presence and absence of growth factor. C. Determine if TSC1 and TSC2 contribute to Akt effects on cell size or survival. Test the importance of the potential Akt phosphorylation sites in tuberin. Together, these studies will help define the roles of the proto-oncogene Akt and the tumor suppressor genes TSC1 and TSC2 in the deregulation of cell metabolism in cancers associated with these genes.