REGULATION OF MITOGENESIS AND APOPTOSIS BY G PROTEINS

G 蛋白对有丝分裂和细胞凋亡的调节

• 批准号: 6519826
• 负责人: TATYANA A VOYNO-YASENETSKAYA
• 金额: $ 28.62万
• 依托单位: UNIVERSITY OF ILLINOIS AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-04-01 至 2004-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6519826
• 关键词: 3T3 cells; BCL2 gene /protein; G protein; apoptosis; biological signal transduction; cell growth regulation; cell line; cysteine endopeptidases; enzyme activity; gel electrophoresis; genetic library; immunoprecipitation; mitogen activated protein kinase; molecular cloning; neoplastic transformation; polymerase chain reaction; protein isoforms; protein structure function; protein tyrosine phosphatase; receptor expression; tissue /cell culture; western blottings; yeast two hybrid system

Cell number is regulated, in part, by a balance between mitogenic and apoptotic responses. Heterotrimeric GTP-binding proteins (G proteins) can transmit growth signals leading to mitogenesis. We have shown that alpha subunits of heterotrimeric G12 and G13 proteins induce mitogenesis and neoplastic transformation in mouse fibroblasts. In contrast, Galpha12 and Galpha13 induce apoptosis in human endothelial cells. Our data suggest that Galpha12 and Galpha13 can stimulate multiple signaling pathways, including Ras and Rho family of monomeric G proteins and the mitogen-activated protein kinase (MAP) pathways. Ras and Rho families of G proteins play an important role in mitogenesis and neoplastic transformation of the cell. However, there is considerably evidence that Ras and Rho families of G proteins can promote apoptosis. The variable effects of Galpha12 and Galpha13 on mitogenic and apoptotic responses could reflect the utilization of the multiple signaling pathways under different circumstances and in different cell types. We will test the hypothesis that Galpha12 and Galpha13 proteins regulate multiple signaling pathways which produce bifurcating signals leading to mitogenic or apoptotic response. To test this hypothesis, we will use the combination of biochemical, cellular, and genetic approaches to investigate the specific signaling pathways leading to G protein-induced mitogenesis or apoptosis. In particular, we will determine the role of Ras and Rho family of G proteins and the MAP kinase pathways in mitogenic and apoptotic responses induced by Galpha12 and Galpha13 proteins. To understand the molecular basis of variable effects of Galpha12 and Galpha13, we will determine the role of caspases and Bcl-2 in the G protein- induced apoptotic response. Finally, we will identify the effector proteins interacting with Galpha12 and Galpha13 using yeast two-hybrid screening of cDNA libraries and will characterize the role of interacting proteins in mediating mitogenic or apoptotic responses. These studies are critical for understanding of the control of tissue proliferation and apoptosis and for design of novel strategies to control proliferation of cancerous cells.

细胞数量的调节，部分，有丝分裂和凋亡反应之间的平衡。 异源三聚体GTP结合蛋白（G蛋白）可以传递导致有丝分裂的生长信号。 我们已经表明，α亚基的异源三聚体G12和G13蛋白诱导小鼠成纤维细胞的有丝分裂和肿瘤转化。 相反，Galpha 12和Galpha 13诱导人内皮细胞凋亡。 我们的数据表明，Galpha 12和Galpha 13可以刺激多个信号通路，包括单体G蛋白的Ras和Rho家族和促分裂原活化蛋白激酶（MAP）通路。 G蛋白的Ras和Rho家族在细胞的有丝分裂和肿瘤转化中起重要作用。 然而，有相当多的证据表明G蛋白的Ras和Rho家族可以促进细胞凋亡。 Galpha 12和Galpha 13对促有丝分裂和凋亡反应的可变影响可以反映在不同情况下和不同细胞类型中多种信号通路的利用。 我们将测试的假设，Galpha 12和Galpha 13蛋白调节多个信号通路，产生分叉信号，导致有丝分裂或凋亡反应。 为了验证这一假设，我们将结合生物化学、细胞学和遗传学方法来研究导致G蛋白诱导的有丝分裂或凋亡的特定信号通路。 特别是，我们将确定Ras和Rho家族的G蛋白和MAP激酶途径的Galpha 12和Galpha 13蛋白诱导的有丝分裂和凋亡反应的作用。 为了理解Galpha 12和Galpha 13可变效应的分子基础，我们将确定半胱天冬酶和Bcl-2在G蛋白诱导的凋亡反应中的作用。 最后，我们将确定的效应蛋白与Galpha 12和Galpha 13使用酵母双杂交筛选的cDNA文库，并将其特征相互作用的蛋白质在介导有丝分裂或凋亡反应的作用。 这些研究对于理解组织增殖和凋亡的控制以及设计控制癌细胞增殖的新策略至关重要。