MOLECULAR MECHANISMS OF POTASSIUM CHANNEL FUNCTION

电压依赖性和钙依赖性钾通道是关键 控制细胞膜兴奋性和信号转导的分子元件 这是神经系统。它们在心脏起搏器活动中起着关键作用 内源性活性神经元在突触的调节中起重要作用 功能。钾离子通道已被证明在血管紧张素转换酶 在许多系统中对发射机释放的控制和调制。 Shaker突触前终末钾通道的变化 果蝇突变体导致动作电位复极延迟和 神经肌肉交界处的过度兴奋。这些影响是 变种人档案中的行为缺陷。在海藻中，调制 神经递质的钾通道已被证明可以增强 突触参与敏感化和联想学习。一个详细的 对钾通道作用的分子机制的认识 将提供对正常和病理性突触功能的洞察 以及引入突触的可塑性。此外，在这方面的进展 渠道功能方面的知识应该为 针对涉及细胞的病理情况设计治疗剂 信号转导过程。我们建议继续研究…… 激动型钾通道失活。我们之前的工作是 建立了快速失活的“球和链”机制 涉及通过氨基末端阻断通道的内口 Shaker多肽的结构域。在上一次赠款期间取得的进展 这一时期导致了对特定氨基酸作用的详细了解 在失活机制中氨基末端区域的酸，以及 上的结合部位的一般生物物理性质 海峡口。下一个资助期的一个主要目标是 确定失活“受体部位”的氨基酸组成成分。 其他实验室和我们之前的工作涉及三个区域 受体位置的潜在部分。我们将使用嵌合通道和 我们的N-末端多肽的范围，以研究这些和其他区域在更多 详细信息以更好地了解受体的特性 位点及其与N-末端失活结构域的相互作用。使用 大电导钙激活钾基因的最新克隆 电压和钙离子分子机制的研究 在这些重要渠道中依赖门控现在是可行的。这些 渠道为此类研究提供了几个优势，使它们成为 是研究通道门控机制的重要工具。我们会 继续我们对这些渠道中的门控的研究，朝着 理解钙离子与电压依赖性之间的相互作用 门控。

Voltage-dependent and Calcium-dependent potassium channels are key molecular elements in the control of membrane excitability and signaling in athe nervous system. They play critical roles in the pacemaker activity of endogenously active neurons and are important in the modulation of synaptic function. Potassium channels have been shown to play a central role in the control and modulation of transmitter release in a number of systems. Alterations in potassium channels in presynaptic terminals of Shaker Drosophila mutants leads to delayed action potential repolarization and hyperexcitability at the neuromuscular junction. These effects underlie the behavioral defects in the mutant files. In Aplysia, modulation of potassium channels by neurotransmitters has been shown to strengthen synapses involved in sensitization and associative learning. A detailed understanding of the molecular mechanisms of potassium channel function will provide insights into normal and pathological synaptic function as well as intro synaptic plasticity. In addition, the advances in the knowledge of channel function should provide a better framework for designing therapeutic agents for pathological conditions involving cellular signal transduction processes. We propose to continue the study of inactivation of Shaker potassium channels. Our previous work has established a "Ball and Chain" mechanism for rapid inactivation that involves block of the internal mouth of the channel by an amino-terminal domain of the Shaker polypeptide. Progress made during the previous grant period has led to a detailed understanding of the role of specific amino acids in the amino-terminal domain in the mechanism of inactivation, and have defined the general biophysical properties of the binding site on the mouth of the channel. A major goal during the next funding period will be to define the amino-acid contributors to the inactivation "receptor site". previous work by other labs and ours has implicated three regions as potential parts of the receptor site. We will use chimeric channels and our range of N-terminal peptides to study these and other regions in more detail to get a better understanding of the properties of the receptor sites and its interaction with the N-terminal inactivation domain. With the recent cloning of large-conductance Calcium-activated potassium channels, studies of the molecular mechanisms of voltage and calcium dependent gating in these important channels are now feasible. These channels offer several advantages for such studies that make them an important tool for the study of channel gating mechanisms.. We will continue our studies of gating in these channels with a direction towards understanding the interactions between calcium and voltage-dependent gating.