Mechanisms of Regulation of NHE-1

NHE-1的调节机制

基本信息

批准号：
7903712
负责人：
John R Raymond
金额：
$ 5.59万
依托单位：
MEDICAL UNIVERSITY OF SOUTH CAROLINA
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-08-20 至 2010-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7903712
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

项目摘要

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（申请人提供）：这是一份经过两次修改的R01续展申请，其目的是研究1型钠质子交换剂NHE-1（也称为产品）快速调节的分子机制。 SLC9A1，溶质载体家族 9A，类型 1)。 NHE-1 无处不在，几乎在每个哺乳动物细胞的质膜上表达。它介导细胞外 Na+ 与细胞内 H+ 的 1:1 交换，从而维持细胞内 pH 值。 NHE-1还在细胞体积维持、有丝分裂、细胞周期调节、细胞凋亡和许多其他细胞功能中发挥细胞特异性作用。 NHE-1 还与临床相关病症有关，例如高血压、左心室肥厚和缺血再灌注损伤。尽管它在哺乳动物细胞中普遍表达并且具有潜在的临床意义，但关于调节这种重要蛋白质的分子机制仍有很多东西有待了解。我们寻求更好地了解 NHE-1 的激活机制。我们提出了一个基于 NHE-1 磷酸化和 CaM 与 NHE-1 结合的想法的模型，破坏了在基础状态下封闭 NHE-1 的质子传感和传输区域的静电系链。系绳的破坏允许环境质子进入 NHE-1 的质子传感和传输区域，从而导致其激活。 CA-II 可能会促进激活，CA-II 可以在“代谢”中与 NHE-1 耦合，并且可以通过滑入静电绳被释放时产生的口袋来进入 NHE-1 的质子传感和传输区域。扰乱了。该模型将在三个具体目标上进行测试：目标#1：我们将研究 Jak2 诱导的 CaM 酪氨酸磷酸化在 NHE-1 激活中的作用。目标#2：我们将研究 2 型碳酸酐酶 (CA-II) 作为增加 NHE-1 活性的关键调节蛋白的作用。目标#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。我们相信，通过重点评估 NHE-1 激活的这种潜在统一机制，该提案得到了显着改进，这是我们之前在该领域工作的自然结果，并且可以作为分子开发的基础。 NHE-1 激活模型。该提议还可以为未来利用核磁共振和/或晶体学方法进行结构实验奠定基础。公共卫生相关性该项目与公共卫生相关，因为NHE-1参与血压、肾功能和心肌收缩的调节。这项工作可能会带来治疗高血压、充血性心力衰竭、心肌病和肾衰竭的新疗法。