Rectification & Block of Ion Channel Currents

描述（由申请人提供）：内向整流K （Kir）通道调节许多组织的兴奋性，一些疾病是由Kir通道基因突变引起的。在之前的研究期间，我们证明了可溶性细胞质因子在强内向整流器中引起内在整流，将这些因子确定为多胺，并证实它们作为“长孔塞”来阻断通道渗透途径。最近两种不同的钾通道孔结构的结晶揭示了钾通道的渗透和门控机制。然而，在基尔通道中整流和门控的结构细节仍不清楚。初步数据使我们对多胺诱导整流的分子细节和Kir通道中的配体门控机制提出了具体的假设。这些假设将在三个实验目的中进行严格检验，利用生物化学和生物物理技术的结合，以及分子建模，以获得以前无法获得的内向整流和门控机制的见解。这项工作将为通过调节Kir通道活性来合理治疗心律失常、癫痫和其他细胞兴奋性疾病提供信息背景。

DESCRIPTION (provided by applicant): Inward rectifying K (Kir) channels regulate excitability in many tissues, and several diseases result from mutations of Kir channel genes. During previous award periods we demonstrated that soluble cytoplasmic factors cause intrinsic rectification in strong inward rectifiers, identified these factors as polyamines, and confirmed that they act as 'long-pore plugs' to block the channel permeation pathway. Recent crystallization of two different K channel pore structures has illuminated mechanisms of permeation and gating in K channels. However, the structural details of rectification and of gating in Kir channels remain unclear. Preliminary data lead us to specific hypotheses regarding the molecular details of polyamine-induction of rectification and of ligand-gating mechanisms in Kir channels. These hypotheses will be critically examined in three experimental Aims, utilizing a combination of biochemical and biophysical techniques, together with molecular modeling to gain previously unobtainable insight to the mechanisms of inward rectification and gating. The work will provide information that will form the background to the development of rational therapies for cardiac arrhythmias, epilepsy and other disorders of cell excitability through modulation of Kir channel activity.