Novel Protein Phosphatases

新型蛋白磷酸酶

• 批准号: 8324719
• 负责人: JACK E DIXON
• 金额: $ 31.84万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-10-01 至 2015-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8324719
• 关键词: Active Sites; Address; Adenoviruses; Affect; Age; Alleles; Anabolism; Animalia; Apoptosis; Attention; Award; Basic Amino Acids; Biochemical; Bioenergetics; Biological Assay; Cardiolipins; Cell physiology; Cells; Complex; Data; Diabetes Mellitus; Dictyostelium discoideum; Differentiation and Growth; Disease; Embryo; Energy Metabolism; Eubacterium; Exhibits; Family; Genes; Genetic Recombination; Genetically Engineered Mouse; Grant; Heart Diseases; Heart failure; In Vitro; Infection; Inner mitochondrial membrane; Ischemia; Kinetics; Light; Link; Lipids; Mediator of activation protein; Membrane; Metabolism; Mitochondria; Mitochondrial Proteins; Morphology; Mouse-ear Cress; Names; Nature; Open Reading Frames; Orthologous Gene; PTEN gene; PTEN protein; Phosphatidyl glycerol; Phosphatidylglycerols; Phosphatidylinositols; Phospholipids; Phosphoric Monoester Hydrolases; Phosphorylation; Plague; Play; Positioning Attribute; Property; Protein Tyrosine Phosphatase; Protein phosphatase; Protista; RNA Interference; Recombinants; Reporting; Role; Signal Pathway; Site; Solutions; Structure; Substrate Specificity; Therapeutic Intervention; United States National Institutes of Health; cell motility; cell type; homologous recombination; human disease; in vivo; inorganic phosphate; insight; knock-down; member; mitochondrial membrane; novel; phosphatidylglycerophosphate; protein expression; public health relevance; recombinase; research study

DESCRIPTION (provided by applicant): Members of the protein tyrosine phosphatase (PTP) super family contain the highly conserved active site motif, Cys-x5-Arg (Cx5R), and are key mediators of a variety of cellular processes including growth, differentiation, motility, metabolism, and programmed cell death. This proposal focuses on the mitochondrial phosphatase, PTPMT1 (formerly PLIP), the first resident mitochondrial phosphatase to be identified and functionally linked to energy metabolism in the cell. PTPMT1 is a highly conserved phosphatase with over 60 orthologs throughout the Animalia, Plantae, Protista, and Eubacteria kingdoms. There is no precedent for PTPs in the mitochondrion, and no known mitochondrial signaling pathways involving reversible phosphorylation. We, therefore, performed several analyses of cells in which PTPMT1 had been ablated. A lipidomic analysis comparing the lipid profile of PTPMTI-ablated versus wild type cells pointed to phosphatidylglycerol phosphate (PGP) as the in vivo substrate for PTPMT1. PGP is an intermediate in cardiolipin biosynthesis, a key component of inner mitochondrial membranes. We propose to: 1) Synthesize PGP for in vitro analyses to demonstrate that PTPMT1 is a PGP phosphatase. We will also use this substrate with a variety of other phosphatases to determine if the ability to convert PGP to PG is an enzymatic activity unique to PTPMT1. Conversely, the ability of PTPMT1 to utilize other lipid phosphate substrates will also be assessed. 2) Address whether PGP phosphatase activity is conserved in selected orthologues. 3) Address the function of PTPMT1 in the inner mitochondrial membrane. We propose to quantitate the effects of PTPMT1 expression on rates of cardiolipin biosynthesis, as well as examine the mitochondrial morphology and bioenergetic status of PTPMT1 deficient cells. 4) Determine the structure of PTPMT1 itself and in combination with PGP. These experiments will allow a detailed understanding of how PTPMT1 exhibits such unusual phospholipid substrate specificity. Our results will shed light on the possible roles of PTPMT1 in various diseases where reduced cardiolipin has been reported, such as ischemia, heart failure and diabetes, and provide insight into novel points of therapeutic intervention for these diseases. PUBLIC HEALTH RELEVANCE: This project is focused on the mitochondrial phosphatase, PTPMT1. We have proposed that its endogenous substrate is phosphatidylglycerol phosphate, an important intermediate in cardiolipin biosynthesis, a key component of mitochondrial membranes. Thus, PTPMT1 function is intimately linked to mitochondrial function, which plays a critical role in ageing and diseases such as diabetes.

描述（由申请人提供）：蛋白质酪氨酸磷酸酶（PTP）的成员超级家族包含高度保守的活性位点基序Cys-X5-ARG（CX5R），并且是多种细胞过程的关键介体，包括生长，分化，差异，运动，代谢性，代谢性和程序性细胞死亡。该提案的重点是线粒体磷酸酶PTPMT1（以前是PLIP），这是第一个驻留的驻留线粒体磷酸酶，并在功能上与细胞中的能量代谢有联系。 PTPMT1是一种高度保守的磷酸酶，在整个动物，植物学，protista和Eubacteria王国中，有60多个直系同源物。线粒体中没有PTP的先例，也没有涉及可逆磷酸化的线粒体信号通路。因此，我们对PTPMT1被消融的细胞进行了几个分析。将PTPMTI-IPAR的脂质谱与磷酸甘油磷酸磷酸甘油（PGP）的脂质分析比较了PTPMT1的体内底物。 PGP是心脏蛋白生物合成的中间体，这是内部线粒体膜的关键组成部分。我们建议：1）合成PGP以进行体外分析，以证明PTPMT1是PGP磷酸酶。我们还将使用与各种其他磷酸酶一起使用该基材来确定将PGP转换为PG的能力是否是PTPMT1独有的酶促活性。相反，还将评估PTPMT1利用其他脂质磷酸盐底物的能力。 2）解决选定的直系同源物中PGP磷酸酶活性是否是保守的。 3）解决内部线粒体膜中PTPMT1的功能。我们建议量化PTPMT1表达对心磷脂生物合成速率的影响，并检查PTPMT1缺陷细胞的线粒体形态和生物能状态。 4）确定PTPMT1本身的结构，并与PGP结合使用。这些实验将详细了解PTPMT1如何表现出这种异常的磷脂底物特异性。我们的结果将阐明PTPMT1在各种疾病中的可能作用，这些疾病已报道了降低的心脂蛋白，例如缺血，心力衰竭和糖尿病，并提供了对这些疾病治疗干预的新颖点。 公共卫生相关性：该项目侧重于线粒体磷酸酶PTPMT1。我们已经提出，其内源性底物是磷脂酰甘油磷酸盐，这是心脏蛋白生物合成的重要中间体，这是线粒体膜的关键成分。因此，PTPMT1功能与线粒体功能密切相关，线粒体功能在衰老和疾病（例如糖尿病）中起关键作用。