CYTOSOLIC MODULATION OF PLASMA MEMBRANE ION TRANSPORT

质膜离子运输的细胞质调节

• 批准号: 3236474
• 负责人: MARK A MILANICK
• 金额: $ 6.53万
• 依托单位: UNIVERSITY OF MISSOURI-COLUMBIA
• 依托单位国家: 美国
• 财政年份: 1986
• 资助国家: 美国
• 起止时间: 1986-08-01 至 1989-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3236474
• 关键词: adenosine triphosphate; adenosinetriphosphatase; calcium transporting ATPase; cell differentiation; cell membrane; chemical structure function; cytoplasm; erythrocytes; heart failure; human tissue; hydrolysis; hypertension; ion transport; membrane potentials; membrane structure; muscular dystrophy; renal failure; sodium potassium exchanging ATPase

The goals of this research are 1) to determine how changes in the cytoplamsic mileau modulate ion transport, 2) to elucidate some of the molecular mechanisms of ion transport, and 3) to understand how changes in ion transport rate influence cellular metabolism, physiology and differentiation. The initial approach is to examine how the separate effects of the intracellular proton concentration, (H+)i, the extracellular proton concentration, (H+)o, the phosphate concentration, (Pi), and the membrane potential, Em, and their interactions modulate the operation of the plasma membrane Na/K and Ca pumps of human red blood cells. Defects in pump activity lead to changes in (Ca), (Na), and (K) which alter key cytoplasmic functions and have been implicated in several disease states including renal and heart failure, hypertension, and muscular dystrophy. Alterations in red cell pump activity have been reported in some red cell diseases, including hereditary stomatocytosis and sickle-cell disease. In many cells, physiological challenges affect the unidirectional Na or Ca influx including mitogen stimulation of cell growth, generally increase Na/K or Ca pump activity. Thus, how the cell senses the increased influx rate needs to be determined as well as how the cell modulates the pump rate in the absence of changes of (Na)i and (Ca)i. Alterations in (H+), Em, and (Pi) are known to occur and if they are not the primary means of cellular regulation they must complement or hinder other regulatory mechanisms. The separate effects of (H+)i and (H+)o will be examined because a) changes in (H+)i and (H+)o require different responses from the cell and b) the effect of H+ on the transport mechanism is often obscured when both (H+)i and (H+)o are varied, especially since recent models for these pumps suggest that H+o (or H+i) is a (alternative) substrate. The combined information from the kinetic effects and from effects due to alterations in free energy will clarify the type of regulation and provide constraints on the models of coupling between ATP hydrolysis, ion movement and charge movement. The techniques and insights developed for the red cell will then be tested, refined and altered to understand the regulatory influence of changes in (H+), (Pi), and Em on the ion transport activity of more complex cells.

本研究的目标是：1）确定 细胞质里程碑调节离子转运，2）阐明一些 离子运输的分子机制，以及3）了解如何改变， 离子转运速率影响细胞代谢、生理和 分化 最初的方法是研究如何分离 细胞内质子浓度（H+）i、细胞外质子浓度（H+）i 质子浓度（H+）o、磷酸盐浓度（Pi）和 膜电位，Em，和它们的相互作用调节的运作， 人红细胞的质膜Na/K和Ca泵。 缺陷 泵活性导致（Ca）、（Na）和（K）的变化， 细胞质的功能，并已牵连在几种疾病状态 包括肾衰竭和心力衰竭、高血压和肌营养不良。 据报道，在某些红细胞中， 这些疾病包括遗传性口细胞增多症和镰状细胞病。 在 许多细胞，生理挑战影响单向钠或钙 包括细胞生长有丝分裂原刺激在内的流入通常增加 Na/K或Ca泵活性。 因此，细胞如何感知增加的流入 需要确定泵浦速率以及单元如何调节泵浦速率 在（Na）i和（Ca）i无变化的情况下。 （H+）、Em和 (Pi)已知会发生，如果它们不是细胞的主要手段， 它们必须补充或阻碍其他监管机制。 的 将检查（H+）i和（H+）o的单独影响，因为a） （H+）i和（H+）o需要来自细胞的不同响应，以及B）效应 当（H+）i和 （H+）O是变化的，特别是因为这些泵的最新模型表明， H+o（或H+i）是（替代）底物。 组合信息 从动力学效应和自由能变化的效应 将澄清监管类型并提供对模型的限制 ATP水解、离子运动和电荷运动之间的耦合。 的 然后将测试针对红细胞开发的技术和见解， 改进和改变，以了解变化的监管影响， （H+）、（Pi）和Em对更复杂细胞的离子转运活性的影响。