Characterization of a Cardiac Transient Outward Current

心脏瞬态外向电流的表征

• 批准号: 6871976
• 负责人: HAROLD CARL STRAUSS
• 金额: $ 35.33万
• 依托单位: STATE UNIVERSITY OF NEW YORK AT BUFFALO
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-06-01 至 2008-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6871976
• 关键词: Xenopus oocyte; chimeric proteins; complementary DNA; conformation; ferrets; gene expression; gene mutation; heart cell; molecular cloning; muscle cells; northern blottings; nucleic acid sequence; polymerase chain reaction; potassium channel; protein structure function; site directed mutagenesis; transfection /expression vector; voltage /patch clamp; voltage gated channel

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===========================================

超出所提供的空间。瞬态外向 K+ 电流 Ito 是心房和心室复极的主要贡献者，被认为是抑制心律失常的重要但尚未探索的治疗靶点。然而，心脏中存在多种不同的心脏 Ito 表型，具有异质的表达模式。还有多个 K+ 通道（X 亚基（Kvl.4、Kv4.2 和 Kv4.3）作为天然 Ito 表型的潜在分子底物。我们证明了 2 个不同 Ito 表型的 Kvl .4 和 Kv4.2/4.3 CC 亚基表达的异质性（与 Kv4.2/4.3 表达相关的快速恢复的 Ito，以及与 Kv4.2/4.3 表达相关的缓慢恢复的 Ito）。左室 与 Kvl.4 表达相关的心内膜肌细胞）。仍然存在一些重要的科学和临床相关问题。其他通道和/或辅助亚基是否对这种电流有贡献和/或形成不同心脏 Ito 表型异质性的基础？这个班级的哪些成员是心中存在的，他们的区域分布是怎样的？ Ito 在不同心房肌细胞类型中的作用是什么？为什么要异地 表达 Kv4.2/4.3 的亚基无法以快速恢复动力学重建 Ito？为了解决这些重要问题，我们重点研究了一类 Ca2+ 结合 Kv 通道相互作用蛋白 (KCMP)，它们是天然 Kv4.x 通道复合物的组成部分。最近发现 KCMP 可以加速异源表达的 Ky4.x pc 亚基的恢复动力学。 为了确定 KChlP 是否是完全重建快速恢复表型所需的缺失调节因子，我们将结合使用分子生物学、免疫荧光 (IF) 定位、原位杂交、生物化学和生物物理技术来阐明 KChlP 调节两个表达的 Kv4.2/4.3 ¿ 亚基的门控特征的机制 （非洲爪蟾卵母细胞、HEK 293 细胞）和雪貂肌细胞中的天然 Ito 表型。我们将定义雪貂心室和心房组织横截面中 Kvl .4、Kv4.2、Kv4.3 和 KChlP 的区域分布模式，然后将该分子数据与从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 心房和心室的。我们还将对人心室中的这些相同亚基进行类似但有限的 IF 定位研究。表演网站==========================================部分 结束=============================================

项目成果

Kinetic properties of Kv4.3 and their modulation by KChIP2b.

Kv4.3 的动力学特性及其 KChIP2b 的调节。

• DOI: 10.1016/s0006-291x(02)00658-7
• 发表时间: 2002
• 期刊: Biochemical and biophysical research communications
• 影响因子: 3.1
• 作者: Wang,Shimin;Patel,SangitaP;Qu,Yujie;Hua,Ping;Strauss,HaroldC;Morales,MichaelJ
• 通讯作者: Morales,MichaelJ

Time- and voltage-dependent components of Kv4.3 inactivation.

Kv4.3 失活的时间和电压依赖性成分。

• DOI: 10.1529/biophysj.105.059378
• 发表时间: 2005
• 期刊: Biophysical journal
• 影响因子: 3.4
• 作者: Wang,Shimin;Bondarenko,VladimirE;Qu,Yu-jie;Bett,GlennaCL;Morales,MichaelJ;Rasmusson,RandallL;Strauss,HaroldC
• 通讯作者: Strauss,HaroldC

Closed-state inactivation in Kv4.3 isoforms is differentially modulated by protein kinase C.

Kv4.3 亚型的闭合状态失活受蛋白激酶 C 的差异调节。

• DOI: 10.1152/ajpcell.00144.2009
• 发表时间: 2009
• 期刊: American journal of physiology. Cell physiology
• 作者: Xie,Chang;Bondarenko,VladimirE;Morales,MichaelJ;Strauss,HaroldC
• 通讯作者: Strauss,HaroldC

The N-terminal domain of a K+ channel beta subunit increases the rate of C-type inactivation from the cytoplasmic side of the channel.

K 通道 β 亚基的 N 端结构域增加了通道细胞质侧的 C 型失活率。

• DOI: 10.1073/pnas.93.26.15119
• 发表时间: 1996
• 期刊: Proceedings of the National Academy of Sciences of the United States of America
• 影响因子: 11.1
• 作者: Morales,MJ;Wee,JO;Wang,S;Strauss,HC;Rasmusson,RL
• 通讯作者: Rasmusson,RL

Heteropoda toxin 2 is a gating modifier toxin specific for voltage-gated K+ channels of the Kv4 family.

• DOI: 10.1016/j.toxicon.2004.11.015
• 发表时间: 2005-03
• 期刊: Toxicon : official journal of the International Society on Toxinology
• 作者: Vladislav V. Zarayskiy;G. Balasubramanian;V. Bondarenko;M. Morales