SIGNAL TRANSDUCTION AND DICTYOSTELIUM DEVELOPMENT

信号转导和盘基菌发育

• 批准号: 2175065
• 负责人: Peter N Devreotes
• 金额: $ 35.11万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1980
• 资助国家: 美国
• 起止时间: 1980-07-01 至 1997-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2175065
• 关键词: SIGNAL; TRANSDUCTION; DICTYOSTELIUM; DEVELOPMENT

As evidenced by the recent cloning of over 140 structurally related hormone and neurotransmitter receptors, signal transduction via seven transmembrane helix proteins is an extremely widespread phenomenon in higher mammals. When excited, these receptors activate heterotrimeric G- proteins, catalyzing exchange of GTP for GDP and dissociation of the alpha- from the (beta gamma-subunits. There are a wide variety of alpha- subunits and beta gamma-subunits which, in turn, can activate a variety of effectors. Molecular genetic studies have contributed to our understanding of the structure and function of the alpha-subunits. Mutations or modification of alpha-subunits are associated with disorders such as cholera, pituitary and thyroid tumors, pseudohypothyroidism, and McKune-Albright syndrome. The G-protein linked signal transduction strategy appeared early in the evolution of eucaryotic cells. These pathways play an fundamental role in chemotaxis, cell-cell signaling, and ligand-induced gene expression in Dictyostelium. In the course of its developmental program, this simple metazoan expresses a family of four cell surface cAMP receptors (cAR1-cAR4), eight G-protein alpha-subunits (Galpha 1-Galpha 8), a beta- subunit (Gbeta), an adenylyl cyclase (ACA), and a phospholipase C-(PLC). Targeted gene disruptions have shown that cAR1, Galpha2-, and ACA are essential for development. This system will be used in a molecular genetic study of 0-protein linked signal transduction pathways. First, complementation of galpha2- (frigid A) cells and suppression of car1- and aca- cells will provide a "read out" or visual screen for site-directed and random mutants of Galpha2. The mutants will be used to assess the role of Galpha2 phosphorylation and delineate the structural domains required for interaction with surface receptors and effectors. Second, a cytosolic regulator of adenylyl cyclase (CRAC), required for GTPgammaS activation of ACA, will be cloned and its mechanism of action investigated. Third, the role of the beta- and gamma-subunits will be investigated. Additional alpha-subunits will be identified and the extent of redundancy among the multiple alpha-subunits will be determined. Finally, the essential role of G-protein linked signal transduction pathways in development will be exploited to screen for novel components of these pathways by suppressing synag and frigid mutants and screening gene tagged cell lines for new synag and frigid mutants.

正如最近140多个结构相关的克隆所证明的 激素和神经递质受体，通过七个 跨膜螺旋蛋白是一种极为广泛的现象 较高的哺乳动物。激发时，这些受体激活异三聚体G- 蛋白质，GTP的催化GDP交换和解离 alpha-来自（beta gamma-subunits。 亚基和β伽玛 - 亚基又可以激活一种品种 效应子。分子遗传研究为我们的 理解α-亚基的结构和功能。 α-亚基的突变或修改与疾病有关 例如霍乱，垂体和甲状腺肿瘤，假甲状腺功能亢进，以及 McKune-Albright综合征。 G蛋白链接的信号转导策略出现在 桉树细胞的进化。这些途径起着基本作用 在趋化性，细胞 - 细胞信号传导和配体诱导的基因表达中 在dictyostelium中。 在其发展计划的过程中， 简单的后生动物表达一个四个细胞表面训练营受体的家族 （CAR1-CAR4），八个G蛋白alpha-subunits（Galpha 1-Galpha 8），一个β- 亚基（GBETA），腺苷酸环化酶（ACA）和磷脂酶C-（PLC）。 靶向基因破坏表明CAR1，GALPHA2-和ACA是 对于发展至关重要。该系统将用于分子 0-蛋白连接的信号转导途径的遗传研究。 第一的， Galpha2-（Frigid A）细胞的互补和CAR1和CAR1和 ACA-单元将提供一个“读取”或视觉屏幕，以进行站点定向 和galpha2的随机突变体。突变体将用于评估 Galpha2磷酸化的作用并描述结构域 与表面受体和效应子相互作用所必需的。第二， GTPGAMMAS所需的腺苷酸环化酶（CRAC）的胞质调节剂 ACA的激活将被克隆及其作用机理 调查。第三，β-和伽玛 - 亚基的作用将是 调查。 将确定其他alpha-subunits，并 多个α-亚基之间的冗余程度将是 决定。最后，G蛋白链接信号的基本作用 开发中的转导途径将被利用为屏幕 这些途径的新成分通过抑制sillag和寒冷 突变体和筛选基因标记了新的siNag和寒冷的细胞系 突变体。