hKCNMB3和hKCNMB4，大电导钙激活钾通道β亚基家族两个成员的克隆与特性分析

hKCNMB3 and hKCNMB4, cloning and characterization of two members of the large-conductance calcium-activated potassium channel beta subunit family.

作者信息

Behrens R, Nolting A, Reimann F, Schwarz M, Waldschütz R, Pongs O

机构信息

Institut für Neurale Signalverarbeitung, ZMNH, Universität Hamburg, Martinistr. 52, D-20246, Hamburg, Germany.

出版信息

FEBS Lett. 2000 May 26;474(1):99-106. doi: 10.1016/s0014-5793(00)01584-2.

DOI:10.1016/s0014-5793(00)01584-2

PMID:10828459

Abstract

We cloned two beta subunits of large-conductance calcium-activated potassium (BK) channels, hKCNMB3 (BKbeta1) and hKCNMB4 (BKbeta4). Profiling mRNA expression showed that hKCNMB3 expression is enriched in testis and hKCNMB4 expression is very prominent in brain. We coexpressed BK channel alpha (BKalpha) and BKbeta4 subunits in vitro in CHO cells. We compared BKalpha/beta4 mediated currents with those of smooth muscle BKalpha/beta1 channels. BKbeta4 slowed activation kinetics more significantly, led to a steeper apparent calcium sensitivity, and shifted the voltage range of BK current activation to more negative potentials than BKbeta1. BKalpha/beta4 channels were not blocked by 100 nM charybdotoxin or iberiotoxin, and were activated by 17beta-estradiol.

摘要

我们克隆了大电导钙激活钾（BK）通道的两个β亚基，即hKCNMB3（BKβ1）和hKCNMB4（BKβ4）。mRNA表达谱显示，hKCNMB3在睾丸中表达丰富，而hKCNMB4在脑中表达非常显著。我们在体外将BK通道α（BKα）亚基和BKβ4亚基共转染到CHO细胞中。我们将BKα/β4介导的电流与平滑肌BKα/β1通道的电流进行了比较。BKβ4使激活动力学更显著地减慢，导致表观钙敏感性更陡峭，并使BK电流激活的电压范围向比BKβ1更负的电位偏移。BKα/β4通道不被100 nM的蝎毒素或iberiotoxin阻断，并被17β-雌二醇激活。