权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Involvement of tyrosine kinase in regulation of ion channel functions and crosstalk between signal transduction systems

酪氨酸激酶参与离子通道功能的调节和信号转导系统之间的串扰

基本信息

批准号：
10470021
负责人：
ISHII Kuniaki
金额：
$ 7.42万
依托单位：
Yamagata University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10470021/
关键词：
human cardiac delayed rectifier phosphorylation tyrosine kinase protein kinase A protein kinase C K^+チャネル共発現系 Herg PYK2

项目摘要

Human cardiac delayed rectifier potassium channel has 2 components, I_<Kr> and I_<KS>. The poreforming subunit of I_<Kr> channel is encoded by HERG and I_<Ks> channel is composed of 2 molecular entities, KvLQT1 and minK.We have investigated on modulation of HERG and KvLQT1-minK channels using a Xenopus oocyte expression system. Stimulation of coexpressed human endothelin receptor (hETR) by ET-1 did not have obvious influence on HERG currents. However, stimulation of coexpressed hETR markedly inhibited KvLQT1-minK currents. To investigate whether tyrosine kinases are involved in the inhibition of the currents by hETR stimulation, oocytes expressing KvLQT1-minK and hETR were pretreated with tyrosine kinase inhibitors. Treatment with tyrosine kinase inhibitors did not attenuate the inhibitory effect of hETR stimulation, but rather enhanced it. Stimulation of hETR is known to activate Ca^<2+> activated Cl^- channel which is present in Xenopus oocytes. Activation of the Cl^- current was transient but obvious at 5 min after hETR stimulation. Tyrosine kinase inhibitors markedly inhibited the enhancement of the Cl^- currents, which suggested that stimulation of hETR caused activation of tyrosine kinases. It has not been determined yet what pathway is involved in activation of tyrosine kinases following hETR stimulation. KvLQT1-minK, hETR and β_1 adrenergic receptor were coexpressed and the effects of receptor stimulation on KvLQTl-minK currents were investigated. Although exclusive modulation of I_<Ks> current by protein kinase A (PKA) and protein kinase C (PKC) has been reported using chemical reagents, we have not observed the exclusive modulation. Effects of extracellular acidosis, which is known to occur in pathophysiological conditions such as ischemia, on HERG currents were also investigated. Most prominent effect of acidosis was acceleration of deactivation kinetics.

人心脏延迟整流钾通道有 2 个成分，I_<Kr> 和 I_<KS>。 I_<Kr> 通道的成孔亚基由 HERG 编码，I_<Ks> 通道由 2 个分子实体 KvLQT1 和 minK 组成。我们研究了使用爪蟾卵母细胞表达系统对 HERG 和 KvLQT1-minK 通道的调节。 ET-1刺激共表达的人内皮素受体(hETR)对HERG电流没有明显影响。然而，刺激共表达的 hETR 显着抑制 KvLQT1-minK 电流。为了研究酪氨酸激酶是否参与 hETR 刺激对电流的抑制，用酪氨酸激酶抑制剂预处理表达 KvLQT1-minK 和 hETR 的卵母细胞。用酪氨酸激酶抑制剂治疗并没有减弱 hETR 刺激的抑制作用，反而增强了它。已知hETR的刺激可激活爪蟾卵母细胞中存在的Ca 2+ 激活的Cl 2 -通道。 Cl^- 电流的激活是短暂的，但在 hETR 刺激后 5 分钟时很明显。酪氨酸激酶抑制剂显着抑制Cl^-电流的增强，这表明刺激hETR引起酪氨酸激酶的激活。目前尚未确定 hETR 刺激后酪氨酸激酶的激活涉及什么途径。共表达KvLQT1-minK、hETR和β_1肾上腺素能受体，并研究受体刺激对KvLQT1-minK电流的影响。尽管已经报道了使用化学试剂对I_<Ks>电流通过蛋白激酶A(PKA)和蛋白激酶C(PKC)的排他性调节，但我们还没有观察到这种排他性调节。细胞外酸中毒（已知发生在缺血等病理生理条件下）对 HERG 电流的影响也得到了研究。酸中毒最显着的影响是加速失活动力学。