HORMONE REGULATED ADENYLYLCYCLASE ISOFORMS

激素调节的腺苷酸环化酶异构体

• 批准号: 2332019
• 负责人: RONALD TAUSSIG
• 金额: $ 17.84万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-02-01 至 2000-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2332019
• 关键词: G protein; Sf9 cell line; adenylate cyclase; enzyme activity; fungal genetics; hormone regulation /control mechanism; mitogen activated protein kinase; mutant; phosphorylation; protein isoforms; protein kinase A; protein kinase C; protein purification; receptor coupling; site directed mutagenesis

DESCRIPTION (Adapted from the applicant's abstract): Regulation of intracellular cyclic AMP concentrations is principally controlled at the level of its synthesis, through the hormonal regulation of adenylylcyclase, the enzyme responsible for the conversion of ATP into cyclic AMP. The adenylylcyclase system is comprised of three components: heptahelical, G protein-coupled receptors for a variety of hormones, neurotransmitters, and autocoids; heterotrimeric G proteins; and the catalytic entity itself. The G proteins regulate the activity of the enzyme in response to the interaction of ligands with an appropriate receptor. This molecular architecture is common to all G protein regulated effector systems identified to date and include hormone regulated phospholipases and ion channels, as well as the light activated cyclic GMP phosphodiesterases. Central to the regulation of adenylylcyclase, or any of the other effector molecules, is the specificity of the G proteins to couple an appropriate receptor to the correct effector. An additional level of regulation is achieved by the cross-talk of different G protein-coupled effector systems, often mediated by the action of downstream protein kinases. The recent cloning of multiple isoforms of adenylylcyclases has permitted the biochemical demonstration that these cyclases are regulated by G proteins and protein kinases in an isoform specific fashion. The two aims of this project are: 1) to determine the precise molecular signals underlying the specificity of recognition of adenylylcyclase by G proteins, and 2) to characterize the role of phosphorylation in the regulation of adenylylcyclase isoforms. Two genetic system (based on the expression of mammalian adenylylcyclases and G protein subunits in yeast) will be used to select for regulatory mutants of both adenylylcyclases and G protein subunits. Isolation of mutant defective in coupling G protein subunits to adenylylcyclases will allow to probe the molecular basis of G protein recognition and regulation of adenylylcyclase. In addition, in vitro and in vivo approaches will be used to elucidate the regulation of specific adenylylcyclase isoforms by phosphorylation. These studies will have a significant impact on the understanding of the mechanisms underlying the regulation of effector systems by G proteins and the intricate cross-talk among different hormone regulated signaling pathways.

描述（改编自申请人摘要）： 细胞内cAMP浓度主要控制在 其合成水平，通过激素调节， 腺苷酸环化酶，负责将ATP转化为 环腺苷酸。 腺苷酸环化酶系统由三个组分组成： 七螺旋，G蛋白偶联受体，用于多种激素， 神经递质和autocoids;异三聚体G蛋白;和 催化剂本身。 G蛋白调节细胞的活性， 酶响应于配体与适当的 受体的 这种分子结构是所有G蛋白所共有的 迄今为止鉴定的受调节的效应子系统包括激素 调节磷脂酶和离子通道，以及光 活化的环GMP磷酸二酯酶。 监管的核心 腺苷酸环化酶或任何其他效应分子是 G蛋白的特异性将合适的受体偶联到 正确的效应器。 另一个监管级别是通过 不同G蛋白偶联效应系统的串扰，通常 由下游蛋白激酶的作用介导。 近期 腺苷酸环化酶的多种同种型的克隆使得 生物化学证明，这些环化酶是由G 蛋白质和蛋白激酶的亚型特异性方式。 两 本项目的目标是：1）确定精确的分子信号 这是G 蛋白质，和2）表征磷酸化的作用， 腺苷酸环化酶亚型的调节。 两个遗传系统（基于 哺乳动物腺苷酸环化酶和G蛋白亚单位在 酵母）将用于选择两者的调节突变体。 腺苷酸环化酶和G蛋白亚单位。 缺陷突变体的分离 将G蛋白亚基与腺苷酸环化酶偶联， G蛋白识别和调控的分子基础 腺苷酸环化酶 此外，将在体外和体内方法， 用于阐明特定腺苷酸环化酶亚型的调节， 磷酸化 这些研究将对 理解调节效应子的潜在机制 系统的G蛋白和复杂的串扰之间的不同 激素调节的信号通路。