Molecular bases of BK channel function and localization

描述（申请人提供）：BK通道几乎无处不在，并执行许多重要的生理功能。通道功能障碍可引起多种疾病，包括癫痫、进行性听力丧失、小脑性共济失调和高血压。BK通道的功能取决于适当的亚细胞定位和与辅助或调节蛋白的相互作用。然而，BK通道亚细胞定位的分子基础尚不清楚，对BK通道辅助/调节蛋白的了解也很有限。探究秀丽隐杆线虫强大的分子遗传学，以鉴定对BK通道功能或亚细胞定位重要的蛋白质。在初步研究中，三个基因突变体（命名为bkip-1、bkip-2和bkip-3）被分离出来，作为一种嗜睡表型的抑制因子，这种表型是由秀丽隐杆线虫BK通道SLO-1的功能获得（gf）异构体的表达引起的。这些突变体的表型包括神经递质释放增加（bkip-1）和SLO-1定位错误（bkip-2和bkip-3）。bkip-1和bkip-2编码新的BK通道相互作用蛋白，而bkip-3仍有待鉴定。在异种表达系统中分析BKIP-1对SLO-1功能特性的影响。本研究旨在验证这三种BKIPs在体内对sl -1功能和/或亚细胞定位很重要，以及秀丽隐杆线虫中存在其他功能相关蛋白的假设。本提案的具体目的是：(1)确定BKIP-1如何调节SLO-1功能；(2)确定BKIP-2和BKIP-3如何控制SLO-1亚细胞定位和/或功能；(3)分离和鉴定抑制SLO-1（gf）引起的嗜睡表型的其他突变体，这些将在未来的研究中进行分析。长期目标是阐明BK通道功能和亚细胞定位的分子基础。公共卫生相关性：BK通道突变可引起多种疾病，包括癫痫、高血压、进行性听力丧失、小脑性共济失调、膀胱过度活动、阴茎勃起功能障碍、肾小球滤过和K+排泄受损以及发作性运动障碍。拟议的研究计划可能会鉴定出对体内BK通道功能和/或亚细胞定位重要的新蛋白。这些信息对于了解BK通道相关疾病的分子基础，以及确定治疗和管理这些疾病的候选药理学靶点具有潜在的重要价值。

DESCRIPTION (provided by applicant): BK channels are almost ubiquitously expressed and perform many important physiological functions. Dysfunction of the channel causes a variety of diseases, including epilepsy, progressive hearing loss, cerebellar ataxia, and hypertension. The function of BK channels depends on proper subcellular localization and interactions with auxiliary or regulatory proteins. However, the molecular basis of BK channel subcellular localization is unknown and only limited knowledge exists about BK channel auxiliary/regulatory proteins. The powerful molecular genetics of C. elegans is explored to identify proteins important to BK channel function or subcellular localization. In preliminary studies, mutants of three genes (named as bkip-1, bkip-2 and bkip-3) were isolated as suppressors of a lethargic phenotype caused by expressing a gain-of-function (gf) isoform of SLO-1, the C. elegans BK channel. Phenotypes of these mutants included increased neurotransmitter release (bkip-1) and SLO-1 mislocalization (bkip-2 and bkip-3). bkip-1 and bkip-2 were found to encode novel BK channel- interacting proteins whereas bkip-3 remains to be identified. BKIP-1 showed several effects on SLO-1 functional properties when analyzed in a heterologous expression system. This proposal is to test the hypotheses that the three BKIPs are important to SLO-1 function and/or subcellular localization in vivo and that there are other functionally related proteins in C. elegans. The specific aims of this proposal are: (1) determine how BKIP-1 regulates SLO-1 function; (2) determine how BKIP-2 and BKIP-3 control SLO-1 subcellular localization and/or function, and (3) isolate and identify additional mutants that suppress the lethargic phenotype caused by SLO-1(gf), which will be analyzed in future studies. The long-term goal is to elucidate the molecular basis of BK channel function and subcellular localization. PUBLIC HEALTH RELEVANCE: Mutations of the BK channel cause a variety of diseases, including epilepsy, hypertension, progressive hearing loss, cerebellar ataxia, overactive bladder, penile erectile dysfunction, impaired renal glomerular filtration and K+ excretion, and paroxysmal dyskinesia. The proposed research program may identify novel proteins that are important to BK channel function and/or subcellular localization in vivo. Such information is potentially of great value to understanding the molecular bases of BK channel-related diseases, and to identifying candidate pharmacological targets for the treatment and management of these diseases.