Mechanisms of Regulation of NHE-1

NHE-1的调节机制

• 批准号: 7653697
• 负责人: John R Raymond
• 金额: $ 26.78万
• 依托单位: MEDICAL UNIVERSITY OF SOUTH CAROLINA
• 依托单位国家: 美国
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-07-10 至 2010-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7653697
• 关键词: Address; Affinity; Amendment; Apoptosis; Area; Belief; Binding; Biochemical; Biological; Calmodulin; Carbonic Anhydrase II; Cardiomyopathies; Cell Cycle Regulation; Cell Volumes; Cell membrane; Cell physiology; Cells; Clinical; Congestive Heart Failure; Crystallography; Development; Electrostatics; Evolution; Family; Foundations; Future; Goals; Hypertension; Kidney Failure; Knowledge; Lead; Learning; Left Ventricular Hypertrophy; Lipids; Literature; Maintenance; Mammalian Cell; Mediating; Membrane; Membrane Lipids; Methodology; Methods; Modeling; Molecular; Molecular Models; Muscle Contraction; Myocardium; Nature; Nucleic Acid Regulatory Sequences; Pathway interactions; Peptides; Phosphorylation; Play; Proteins; Protons; Public Health; Reagent; Regulation; Renal function; Reperfusion Injury; Role; Slide; Sodium; Stimulation of Cell Proliferation; Stimulus; Structure; Testing; Tyrosine Phosphorylation; Ursidae Family; Work; base; blood pressure regulation; carbonate dehydratase; clinically relevant; extracellular; genetic regulatory protein; improved; insight; molecular modeling; novel; public health relevance; research study; solute

DESCRIPTION (provided by applicant): This is a twice-amended R01 renewal application, the purpose of which is to study the molecular mechanisms of the rapid regulation of the type-1 sodium-proton exchanger, NHE-1 (also known as product of SLC9A1, solute carrier family 9A, type 1). NHE-1 is ubiquitous, being expressed on the plasma membrane of virtually every mammalian cell. It mediates the 1:1 exchange of extracellular Na+ for intracellular H+, thereby maintaining intracellular pH. NHE-1 also plays cell-specific roles in cell volume maintenance, mitogenesis, cell- cycle regulation, apoptosis and a host of other cellular functions. NHE-1 has also been implicated in clinically relevant conditions such as hypertension, left ventricular hypertrophy, and ischemia-reperfusion injury. Despite its ubiquitous expression in mammalian cells and its potential clinical relevance, much remains to be learned regarding the molecular mechanisms through which this important protein is regulated. We seek a better understanding of the mechanisms through which NHE-1 is activated. We propose a model based on the idea that phosphorylation of NHE-1 and binding of CaM to NHE-1, disrupt electrostatic tethers that occlude the proton sensing and transport regions of NHE-1 in its basal state. Disruption of the tethers allows access of ambient protons to the proton sensing and transport regions of NHE-1, thus resulting in its activation. The activation is potentially facilitated by CA-II, which could couple to NHE-1 in a "metabolon", and which could gain access to the proton sensing and transport regions of NHE-1 by sliding into a pocket created when the electrostatic tethers are disrupted. This model will be tested in three specific aims: Aim #1: We will examine the role of Jak2-induced tyrosine phosphorylation of CaM in the activation of NHE-1. Aim #2: We will examine the role of carbonic anhydrase type 2 (CA-II) as a key regulatory protein that increases the activity of NHE-1. Aim #3: We will examine the role of electrostatic interactions involving the carboxyl terminus of NHE-1 in its activation. We believe that the proposal has been significantly improved by focusing on evaluating this potentially unifying mechanism of activation of NHE-1, which is a natural outgrowth of our previous work in this area, and which could serve as the foundation for the development of a molecular model for the activation of NHE-1. This proposal could also lay the foundation for future structural experiments utilizing NMR and/or crystallography methods. PUBLIC HEALTH RELEVANCE This project is relevant to public health in that NHE-1 is involved in the regulation of blood pressure, kidney function and heart muscle contraction. The work could lead to new therapies for hypertension, congestive heart failure, cardiomyopathies and kidney failure.

描述（由申请人提供）：这是两次对R01的续订应用，其目的是研究1型钠 - 钠 - 普罗替型交换器快速调节的分子机制NHE-1（也称为SLC9A1的乘积，SLC9A1的产物，Solute Carrier Carrier家族9A，类型1）。 NHE-1无处不在，在几乎每个哺乳动物细胞的质膜上表达。它介导细胞内H+的细胞外Na+的1：1交换，从而维持细胞内pH。 NHE-1在细胞体积维持，有丝分裂发生，细胞周期调节，细胞凋亡和许多其他细胞功能中还扮演细胞特异性作用。 NHE-1也与临床相关的疾病有关，例如高血压，左心室肥大和缺血 - 再灌注损伤。尽管它在哺乳动物细胞中无处不在及其潜在的临床相关性，但有关这种重要蛋白质受调节的分子机制仍有许多尚待学习。我们寻求更好地理解NHE-1被激活的机制。我们提出了一个基于以下想法的模型，即NHE-1的磷酸化和CAM与NHE-1的结合，破坏静电三链，该静电构成静电构，从而阻塞了NHE-1的质子传感和运输区域的基础状态。割伤的破坏允许将环境质子进入NHE-1的质子传感和运输区域，从而导致其激活。 CA-II可能会促进该激活，该激活可能会在“ Mepabolon”中将其搭配到NHE-1，并且可以通过滑入静电tethers时会产生的口袋来访问NHE-1的质子传感和运输区域。该模型将以三个特定目的进行测试：目标＃1：我们将研究CAM的JAK2诱导的CAM磷酸化在NHE-1激活中的作用。 AIM＃2：我们将研究碳酸酐酶2型（CA-II）作为增加NHE-1活性的关键调节蛋白的作用。 AIM＃3：我们将研究涉及NHE-1羧基末端的静电相互作用在其激活中的作用。我们认为，通过专注于评估NHE-1激活的这种潜在统一的机制，这是我们以前在这一领域的自然产物，可以作为开发NHE-1激活的分子模型的基础，从而显着改善了该提案。该建议还可以为使用NMR和/或晶体学方法的未来结构实验奠定基础。 公共卫生相关性 该项目与公共卫生有关，因为NHE-1参与了血压，肾脏功能和心肌收缩的调节。这项工作可能导致新的高血压，充血性心力衰竭，心肌病和肾衰竭的疗法。