Ion Channel Transporter Interactions

项目摘要 电压门控钾(Kv)通道是由四聚体形成孔的α亚基产生的，通常在 与其他不成孔的β亚基形成的复合体。这个项目的重点是两个非常重要的5人 Kv通道亚基家族：Kcnqα亚基和Kcneβ亚基。KCNQ1在 心脏和许多上皮细胞；它在可兴奋和不可兴奋细胞中的不同生理作用是 通过与5个KCNE单跨膜域β亚基的相互作用而促进。KCNEβ亚基 被广泛表达并调节大多数Kv亚家族甚至其他通道类型的α亚单位。 KCNQ2-5KCNQ2-5α亚基，特别是KCNQ2/3异构体，因其在产生 神经元M电流，它调节神经元的兴奋性。KCNQ2-5在其他组织中也有表达， 包括血管系统和听觉系统。反映它们的生理重要性，KCNQ或 KCNE基因会导致各种疾病，如心律失常、糖尿病、酸中毒、甲状腺功能减退和 癫痫。我们使用高度集成的方法来研究KCNQ和KCNQ的分子机制基础 KCNE生物学和病理生理学。这包括基因敲除和敲入小鼠模型，细胞 电生理学、运输和放射配基分析、转录学、各种成像方式、结构- 功能和生化技术。在未来五年，我们的目标是应对几个突出的挑战 在该领域，追求以下新颖的研究方向。(1)与KCNQ或KCNE相关的遗传性疾病 基因通常是高度复杂的多系统疾病，因为这些基因通常以多个 纸巾。然而，传统的方法往往涉及到专注于单一组织。我们的目标是剖析 通过采用多系统方法和首先了解基于KCNQ和KCNE的疾病 这些亚基相互交织的生理功能的分子基础。(2)我们最近发现KCNQ 通道与几种不同类型的钠偶联溶质形成生理必需的复合体 传送者。我们将研究新型信号纳米结构域的分子机制和作用，这些结构域由 “Chansporter”复合体。(3)我们最近发现，一些神经递质及其类似物可以 直接激活特定的神经元KCNQ，这是一种具有潜在广泛影响的范式转变。我们会 研究它的生理相关性，分子机制，以及与共同组装的转运蛋白的串扰。 (4)我们将探索几个新发现的KCNQ和KCNQ的分子基础和生理意义。 涉及例如淀粉样前体蛋白C99片段和焦点黏附蛋白的KCNE相互作用， 泰斯汀。这个项目的工作将剖析由离子通道促进的丰富的信号传递谱，包括 KCNQ和/或KCNE亚单位，在各种不同的器官系统和细胞类型中。我们的目标是 了解KCNQ/KCNE相关生物过程的潜在机制，并阐明它们是如何 在疾病状态下感到不安，以及如何利用它们来开发更安全、更有效的疗法。

Project Summary Voltage-gated potassium (Kv) channels are generated by tetramers of pore-forming α subunits, often in complexes with other, non-pore-forming β subunits. This project is focused on two highly important, 5-member families of Kv channel subunits: the KCNQ α subunits and the KCNE β subunits. KCNQ1 is essential in the heart and numerous epithelia; its diverse physiological roles in both excitable and non-excitable cells are facilitated by interaction with each of the 5 KCNE single-transmembrane domain β subunits. KCNE β subunits are widely expressed and regulate α subunits from most Kv subfamilies, and even other channel types. KCNQ2-5 α subunits, especially KCNQ2/3 heteromers, are best known for their essential role in generating the neuronal M-current, which regulates neuronal excitability. KCNQ2-5 are also expressed in other tissues, including the vasculature and auditory system. Reflecting their physiologic importance, disruption of KCNQ or KCNE genes causes disorders as diverse as cardiac arrhythmia, diabetes, achlorhydria, hypothyroidism, and epilepsy. We use a highly integrated approach to investigate the molecular mechanistic bases for KCNQ and KCNE biology and pathophysiology. This includes both knockout and knock-in mouse models, cellular electrophysiology, transport and radioligand assays, transcriptomics, various imaging modalities, structure- function and biochemical techniques. In the next five years, we aim to address several outstanding challenges in the field, pursuing the following novel research directions. (1) Inherited disorders linked to KCNQ or KCNE genes are often highly complex, multi-system diseases because the genes are typically expressed in multiple tissues. Yet, traditional approaches often involve focusing on a single tissue. We aim to dissect the basis for KCNQ- and KCNE-based diseases by embracing multi-system approaches and by first understanding the molecular basis for the intertwining physiological functions of these subunits. (2) We recently found that KCNQ channels form physiologically essential complexes with several different types of sodium-coupled solute transporters. We will study the molecular mechanisms and roles of novel signaling nanodomains created by “chansporter” complexes. (3) We very recently discovered that some neurotransmitters and their analogs can directly activate specific neuronal KCNQs, a paradigm shift with potentially widespread ramifications. We will investigate its physiological relevance, molecular mechanisms, and crosstalk with co-assembled transporters. (4) We will pursue the molecular basis and physiological importance of several newly discovered KCNQ and KCNE interactions involving, e.g., Amyloid Precursor Protein C99 fragment, and the focal adhesion protein, Testin. Work in this project will dissect the rich repertoire of signaling facilitated by ion channels containing KCNQ and/or KCNE subunits, in a variety of different organ systems and cell types. The goals are to understand the mechanisms underlying KCNQ/KCNE-linked biological processes, and elucidate how they are perturbed in disease states, and how they can be leveraged to develop safer, more effective therapeutics.