MODELS FOR GENETIC DISORDERS OF CALCIUM TRANSPORT

这项建议的长期目标是制定一个详细的 了解特异性Ca/2+泵在心血管和 体内肺生理学。正在研究的Ca/2+转运ATP酶 肌浆网Ca/2+-ATP酶（SERCAs）， 螯合细胞内储存细胞器和血浆中的Ca/2+ 膜Ca/2+-ATP酶（PMCAs），其将Ca/2+从细胞中挤出。 很明显，SERCA和PMCAs作为效应分子， Ca/2+稳态和信号传导的关键方面，以及兴奋- 肌肉中的收缩耦合;然而，个体的特定作用 对同种型了解甚少。为了获得这些信息，我们 开发在每个Ca/2+泵中具有突变的小鼠模型。我们有 制备具有SERCA 2、SERCA 3和PMCA 2无效突变的小鼠，并且具有 在SERCA 2杂合突变体中证实了心脏功能缺陷， 血管内皮和上皮依赖性舒张缺陷， SERCA 3无效突变体中的肺平滑肌。在目标1中，我们将开发 在PMCA 1和PMCA 4基因中具有无效突变的小鼠， 开发一种带有修饰的PMCA 1基因的小鼠， 普遍存在的PMCA 1b变体，而不是具有酸性钙调蛋白的变体 限制在可兴奋组织的结合域。这些实验 将检验单个Ca/2+泵的一般假设， 对器官特定功能的基本管家，并可能揭示 意想不到的表型，产生关于特定功能的见解 这些泵。在目标2中，我们将分析发展和 每个Ca/2+泵突变的组织病理学后果， 并将使用完整动物和分离组织进行研究 为了评估这些泵在心血管疾病中的生理作用， 肺组织这些实验将测试SERCA的假设， 和PMCA泵调节心脏收缩力以及肺和血管 平滑肌张力和收缩力，进而影响心脏 功能、气道阻力和动脉血压。我们预计 这六种突变小鼠的生命将成为 对分析Ca/2+转运机制有价值的模型 ATP酶调节心血管、肺和心血管系统的生理功能。 其他组织。

The long-term objective of this proposal is to develop a detailed understanding of the role of specific Ca/2+ pumps in cardiovascular and pulmonary physiology in vivo. The Ca/2+-transporting ATPases being studied are the sarco(endo)plasmic reticulum Ca/2+-ATPases (SERCAs), which sequester Ca/2+ in intracellular storage organelles, and the plasma membrane Ca/2+-ATPases (PMCAs), which extrude Ca/2+ from the cell. It is clear that SERCAs and PMCAs serve as effector molecules controlling critical aspects of Ca/2+ homeostasis and signaling, and excitation- contraction coupling in muscle; however, the specific roles of individual isoforms are poorly understood. To obtain this information we are developing mouse models with mutations in each of the Ca/2+ pumps. We have prepared mice with SERCA2, SERCA3, and PMCA2 null mutations, and have demonstrated defective cardiac function in SERCA2 heterozygous mutants and defective endothelium and epithelium dependent relaxation of vascular and pulmonary smooth muscle in SERCA3 null mutants. In aim 1 we will develop mice with null mutations in the PMCA1 and PMCA4 genes, and will also develop a mouse with a modified PMCA1 gene that will produce only the ubiquitous PMCA1b variant, and not the variants with an acidic calmodulin binding domain that are restricted to excitable tissues. These experiments will test the general hypotheses that individual Ca/2+ pumps serve essential housekeeping on organ-specific functions, and may reveal unexpected phenotypes that yield insights regarding the specific functions of these pumps. In aim 2 we will analyze the developmental and histopathological consequences of mutations in each of the Ca/2+ pumps, and will perform studies using both the intact animal and isolated tissues to assess the physiological role of these pumps in cardiovascular and pulmonary tissues. These experiments will test the hypotheses that SERCA and PMCA pumps regulate cardiac contractility and pulmonary and vascular smooth muscle tone and contractility, which in turn affects cardiac function, airway resistance, and arterial blood pressure. We anticipate that the six mutant mouse lives developed in this proposal will become valuable models for analysis of the mechanisms by which Ca/2+-transporting ATPases modulate physiological functions of cardiovascular, pulmonary, and other tissues.