K+ channel complexes: assembly, trafficking and function

描述(申请人提供)：这项研究的长期目标是阐明确保钾(K+)通道与适当的膜嵌入调节亚基组装以实现适当的生理功能的分子和细胞机制。KCNE调节亚基是一类与四聚体电压门控K+通道共同组装的1型跨膜肽，提供在各种细胞和组织中发挥作用所需的电多样性。这项建议研究KCNQ1-KCNE K+通道复合体，使钾进入内淋巴，维持肠上皮细胞盐和水的动态平衡，并产生心脏iKs电流。这一建议有三个目标：(1)我们将建立具有不同四聚结构域的K+通道-KCNE复合体的组装机制，并确定与疾病相关的突变如何直接影响共组装。(2)我们将确定内质网中错误组装的K+通道亚基的四级结构。(3)我们将确定KCNE亚基是否通过衍生的蝎子毒素和差异突变的KCNQ1亚基的组合来不对称地调节离子传导亚基。

DESCRIPTION (provided by applicant): The long-term goal of this research is to elucidate the molecular and cellular mechanisms that ensure potassium (K+) channels assemble with the appropriate membrane-embedded regulatory subunits for proper physiological function. The KCNE regulatory subunits are a class of type 1 transmembrane peptides that co-assemble with tetrameric voltage-gated K+ channels, providing the electrical diversity needed to function in a wide-variety of cells and tissues. This proposal investigates KCNQ1-KCNE K+ channel complexes that enable potassium ingress into the endolymph, maintain salt and water homeostasis in intestinal epithelia, and generate the cardiac IKs current. There are three aims to this proposal: (1) We will establish assembly mechanisms for K+ channel-KCNE complexes with structurally different tetramerization domains and determine how the disease-associated mutations directly affect co-assembly. (2) We will determine the quaternary structures of misassembled K+ channel subunits in the endoplasmic reticulum. (3) We will determine whether KCNE subunits asymmetrically modulate the ion-conducting subunits using a combination of derivatized scorpion toxins and differentially-mutated KCNQ1 subunits.