Characterization of a Cardiac Transient Outward Current

超出所提供的空间。瞬时外向K+电流Ito是心房和心室复极的主要因素，被认为是抑制心律失常的重要但尚未开发的治疗靶点。然而，在心脏中存在多种不同的Ito表型和异质表达模式。还有多个K+通道(X亚基（kv4、Kv4.2和Kv4.3）作为原生Ito表型的潜在分子底物。我们证明了Kvl的异质性。4和Kv4.2/4.3 CC亚基表达2种不同的Ito表型（快速恢复的Ito与Kv4.2/4.3表达相关，缓慢恢复的Ito在左心内膜肌细胞中与kv4表达相关）。几个重要的科学和临床相关问题仍然存在。其他通道和/或辅助亚基是否有助于这种电流和/或形成不同心脏Ito表型异质性的基础？这一类的哪些人在心里？他们的区域分布是什么？Ito在不同心房肌细胞类型中的作用是什么？为什么异源表达的Kv4.2/4.3 a亚基不能快速重建Ito ？为了解决这些重要的问题，我们专注于一类Ca2+结合Kv通道相互作用蛋白（KCMPs），它们是天然Kv4的组成部分。X通道复合物。KCMPs最近被发现可以加速异源表达Ky4的恢复动力学。X个PC亚单位。以确定是否kchlp是完全重建快速恢复所需的缺失调节因子！我们将结合分子生物学、免疫荧光（IF）定位、原位杂交、生化和生物物理技术来阐明KChlPs调节雪貂肌细胞中表达的Kv4.2/4.3¿亚基（爪蟾卵细胞、HEK 293细胞）和天然Ito表型的门控特性的机制。我们将定义Kvl的区域分布模式。4、Kv4.2、Kv4.3和KChlPs在雪貂心室和心房组织横截面上的表达，然后将这些分子数据与从心房和心室特定解剖区域分离的肌细胞中的Ito功能膜片钳分析相关联。我们还将在人类心室中对这些相同的亚基进行类似但有限的IF定位研究。网站性能 ======================================== 节结束 ===========================================

EXCEED THE SPACE PROVIDED. The transient outward K+ current, Ito, is a major contributor to atrial and ventricular repolarization and is thought to be an important but unexplored therapeutic target for arrhythmia suppression. However, there are multipledistinctcardiac Ito phenotypes with heterogeneous expression patterns in the heart. There are also multiple K+ channel (X subunits (Kvl.4, Kv4.2, and Kv4.3) that serve as potential molecular substrates for native Ito phenotypes. We demonstrated heterogeneity of Kvl .4 and Kv4.2/4.3 CC subunit expression of 2 distinct Ito phenotypes (a rapidly recovering Ito which correlates with Kv4.2/4.3 expression, and a slowly recovering Ito in LV endocardial myocytes which correlates with Kvl.4 expression). Several important scientific and clinically relevant questions remain. Do other channels and/or ancillary subunits contribute to this current and/or form the basis forthe heterogeneity of distinct cardiac Ito phenotypes? Which members of this class are present in heart and what is their regional distribution? What is the role of Ito in different atrial myocyte types? Why do heterologously expressed Kv4.2/4.3 a subunits fail to reconstitute the Ito with rapid recovery kinetics? To address these important questions, we have focused on a class of Ca2+-binding Kv channel interacting proteins (KCMPs) that are integral components of native Kv4.x channel complexes. KCMPs haverecently been discovered to accelerate the recovery kinetics of heterologously expressed Ky4.x pc subunits. To determine if KChlPs are the missing modulatory factors needed to fully reconstitute the rapidly recovering !, phenotype, we will use a combination of molecularbiological, immunofluorescent (IF) localization, insitu hybridization, biochemical,and biophysical techniques to elucidate the mechanisms by which KChlPs modulate the gating characteristics of both expressed Kv4.2/4.3 ¿ subunits (Xenopus oocytes, HEK 293 cells) and native Ito phenotypes in ferret myocytes. We will define the regional distribution patterns of Kvl .4, Kv4.2, Kv4.3, and KChlPs in ferret ventricular and atrial tissue cross sections and then relate this molecular data to functional patch clamp analysis of Ito in myocytes isolated from specific anatomical regions of the atrium and ventricle. We will also conduct a similar but limited IF localizationstudy of these same subunits in the human ventricle. PERFORMANCE SITE ========================================Section End===========================================