CYTOSOLIC MODULATION OF PLASMA MEMBRANE ION TRANSPORT

这项研究的目标是1)确定如何改变 细胞质对离子转运的调节，2)阐明一些 离子传输的分子机制，以及3)了解如何改变 离子转运速率影响细胞代谢、生理和 差异化。最初的方法是检查独立的 胞内质子浓度(H+)i、胞外质子浓度的影响 质子浓度(H+)O，磷酸盐浓度(PI)，以及 膜电位Em和它们的相互作用调节 人红细胞质膜Na/K和Ca泵。中的缺陷 泵活动导致改变关键的(Ca)、(Na)和(K)的变化 细胞质的功能，并与几种疾病状态有关 包括肾功能衰竭、心力衰竭、高血压和肌肉营养不良。 据报道，在一些红细胞中，红细胞泵活性发生了变化。 疾病，包括遗传性口腔细胞增多症和镰状细胞病。在……里面 许多细胞、生理挑战影响单向钠或钙 包括丝裂原在内的内流刺激细胞生长，一般都会增加 Na/K或Ca泵活性。因此，细胞如何感知增加的内流 需要确定泵浦速率以及细胞如何调节泵浦速率 在(Na)I和(Ca)I没有变化的情况下，(H+)、Em和 (PI)是已知发生的，如果它们不是细胞的主要手段 监管它们必须补充或阻碍其他监管机制。这个 将分别考察(H+)i和(H+)o的影响，因为a)在 (H+)i和(H+)o需要来自细胞的不同反应，以及b)效果 当(H+)I和(H+)I同时存在时，H+在传输机制上的作用常常被遮挡 (H+)O有多种，特别是因为最近这些泵的型号表明 H+O(或H+I)是一种(替代)底物。综合信息 由动能效应和由自由能变化引起的自效应 将澄清监管的类型并提供对模型的约束 ATP水解、离子运动和电荷运动之间的耦合。这个 然后将测试为红细胞开发的技术和见解， 经过改进和修改，以了解 (H+)、(PI)和Em对更复杂细胞的离子转运活性的影响。

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.