Properties of Calcium Pumping ATPase

钙泵 ATP 酶的特性

• 批准号: 6541634
• 负责人: JOHN T PENNISTON
• 金额: $ 31.46万
• 依托单位: MAYO CLINIC ROCHESTER
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-07-01 至 2006-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6541634
• 关键词: affinity chromatography; binding sites; calcium channel; calcium flux; calcium transporting ATPase; calmodulin; chemical binding; electron microscopy; emission spectrometry; enzyme activity; enzyme mechanism; enzyme structure; isozymes; membrane proteins; mutant; polymerase chain reaction; protein isoforms; protein structure function; western blottings

DESCRIPTION (provided by applicant): Studies on the properties of the calcium ion pumping ATPase of plasma membranes will be continued. These calcium ion pumps exist in the plasma membranes of heart, smooth muscle, kidney, brain, intestinal epithelium, erythrocyte and many other cell types. They are involved in control of intracellular free calcium levels in cells of all kinds, and in movement of calcium ions across cell layers such as the intestinal and kidney tubule epithelia. Information about the regulation of these pumps may thus give information relevant to hypertension and kidney disease, among other conditions. The pump consists of a single polypeptide chain of molecular weight 127,000-137,000 (the exact molecular weight depends on the isoform). Four genes encode different isoforms, and additional forms are created by alternate splices. We have succeeded in expressing this pump in COS and insect cells and have developed assay systems for determining the activity of the expressed enzyme, its binding of calmodulin and of calcium ions. We propose studies designed to extend our knowledge of the function of the different isoforms of this enzyme, and of the calmodulin-binding and calcium ion-binding residues. We will make measurements of the nitrophenyl phosphatase activity, of the rates of the activation of the pump and of the binding of calmodulin. Measurements will also be made to observe the memory of the pump for its previous history of calcium ion exposure. These measurements will be made on appropriately altered forms of the pump and on the different isoforms.

描述（由申请人提供）：将继续有关质膜钙离子泵送ATPase的性质的研究。这些钙离子泵存在于心脏，平滑肌，肾脏，大脑，肠上皮，红细胞和许多其他细胞类型的质膜中。它们参与了各种细胞中细胞内游离钙水平的控制，以及钙离子跨细胞层的运动，例如肠道和肾小管上皮。因此，有关这些泵调节的信息可能会提供与高血压和肾脏疾病有关的信息。 该泵由一个分子量的单个多肽链组成127,000-137,000（确切的分子量取决于同工型）。四个基因编码不同的同工型，并通过替代接头创建其他形式。我们成功地在COS和昆虫细胞中表达了该泵，并开发了用于确定表达酶的活性，钙调蛋白和钙离子的结合的测定系统。我们提出的研究旨在扩展我们对该酶不同同工型以及钙调蛋白结合和钙离子结合残基的功能的知识。我们将测量硝基苯磷酸酶活性，泵的激活速率和钙调蛋白的结合。还将进行测量，以观察泵的先前钙离子暴露史的记忆。这些测量将以泵的适当变化形式和不同的同工型进行。