CHLORIDE TRANSPORT IN NERVE AND MUSCLE

这是一项研究两种不同氯离子传输机制的提议； 这两种物质似乎都广泛分布在动物细胞中。一 机制利用氯、钠和HCO3的运动来挤压或中和 细胞内酸度。在这份提案中，我们将研究这个系统是如何 由酸性的细胞内pH激活，以及它是如何从明显的 一种更复杂的依赖于Na和HCP3的酸的c1/c1交换机制 挤出机。我们的中心假设是依赖于ATP的磷酸化 在这些事件中扮演了关键角色。我们将对离子进行详细的研究 传输以获得有关该传输的定量动力学信息 机制。第二个要研究的氯离子迁移机制是 钠、钾、氯联合转运蛋白。这款传送器也需要ATP，但 大概不是因为能量或热力学方面的原因。我们相信 磷酸化也参与了这一活性的调节。 传送器。在这两种交通工具中，我们都将学习基本交通工具 特性以及刺激和/或抑制试剂的效果 蛋白激酶和蛋白磷酸酶来证实我们的 蛋白质磷酸化转运激活假说。 这些研究将在巨细胞(鱿鱼巨轴突和 藤壶巨型肌肉纤维)。它们的巨大尺寸使我们可以使用 同时控制细胞内和细胞外的细胞内透析技术 内容。该方法允许测量单向离子通量 通过这些氯离子传输机制，我们将使用 放射性同位素标记的配体尝试标记和部分 确定参与转运过程的膜蛋白(S)。

This is a proposal to study two different chloride transport mechanisms; both of which appear to be widely distributed in animal cells. One mechanism uses movements of C1, Na and HCO3 to extrude or neutralize intracellular acidity. In this proposal we will examine how this system is activated by acidic intracellular pH and how it changes from an apparent C1/C1 exchange mechanism to a more complicated Na and HCP3 - dependent acid extruder. Our central hypothesis is that ATP-dependent phosphorylation plays a key role in these events. We will perform detailed studies of ion transport to obtain quantitative kinetic information about this transport mechanism. The second chloride transport mechanism to be studied is the Na, K, Cl co-transporter. This transporter also requires ATP but presumably not for energetic or thermodynamic reasons. We believe phosphorylation is also involved for the regulation of activity by this transporter. In both transporters we will study fundamental transport properties as well as the effects of agents to stimulate and/or inhibit protein kinases and protein phosphatases in an effort to substantiate our hypothesis of transport activation via protein phosphorylation. These studies will be conducted on giant cells (squid giant axon and barnacle giant muscle fibers). Their large size allows us to use the technique of intracellular dialysis to control both intra-and extracellular contents. The method permits the measurement of unidirectional ion fluxes by these chloride transport mechanisms, we will use radioactive-isotope-labelled ligands to attempt to label and partially identify the membrane protein(s) involved in the transport processes.