STRUCTURE AND REGULATION OF PHOSPHOPROTEIN PHOSPHATASES

磷酸蛋白磷酸酶的结构和调控

• 批准号: 3072464
• 负责人: ANNA A DEPAOLI-ROACH
• 金额: $ 5.72万
• 依托单位: INDIANA UNIV-PURDUE UNIV AT INDIANAPOLIS
• 依托单位国家: 美国
• 财政年份: 1987
• 资助国家: 美国
• 起止时间: 1987-07-01 至 1989-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3072464
• 关键词: antibody; complementary DNA; diabetes mellitus; enzyme complex; enzyme inhibitors; enzyme mechanism; enzyme structure; enzyme substrate; epinephrine; gene expression; genetic manipulation; guinea pigs; insulin; laboratory mouse; laboratory rabbit; laboratory rat; molecular cloning; phosphoproteins; phosphorylation; protein structure; starvation; striated muscles

Covalent phosphorylation of proteins plays a central role in the control of many cellular processes by hormones such as insulin and epinephrine. Part of this regulation involves the enzymes responsible for dephosphorylating proteins, the phosphoprotein phosphatases. This project addresses one of the main classes of protein phosphatase found in cells, what will be termed "type 1" phosphatase (one characteristic of such enzymes is that their catalytic subunit is inhibited by the heat stable phosphatase inhibitor proteins, inhibitor-1 inhibitor-2). Knowledge of the structure and regulation of these enzymes is incomplete. A primary objective will be to establish the number and structures of the native forms of this class of enzyme. Methods to be applied will include (1) conventional protein purification, (2) immunological methods, and (3) recombinant DNA techniques. Purified high molecular weight forms of type 1 phosphatase will be characterized and compared with known enzymes of simpler structure, namely the isolated catalytic subunit, Cl, and the ATP-Mg-dependent phosphatase. The functional roles of non-catalytic subunits will be investigated, particularly in relation to control of enzyme activity. Special attention will be paid to phosphorylation of phosphatases since there is good reason to believe that phosphorylation of the inhibitor-2 component of the ATP-Mg-dependent phosphatase is related to its activation. Possible controls mediated by small molecules will be evaluated. Models for the short-term intracellular control of phosphatase activity will employ mouse diaphragms exposed to insulin and/or epinephrine. Immunological methods will be applied to analyze the phosphorylation of inhibiton 2 and other phosphatase components, as well as phosphatase activity. Success in this investigation can have widespread importance since this class of phosphatase is likely to be involved in the control of many cellular processes. Any mechanistic link to the action of hormones, especially insulin, will be of particular interest in understanding how insulin functions normally. Impaired phosphatase, however, could be a determining factor in some types of diabetes.

蛋白的共价磷酸化在控制