大鼠脑Kv通道β亚基的功能特性

Functional characterization of Kv channel beta-subunits from rat brain.

Heinemann S H, Rettig J, Graack H R, Pongs O

Max-Planck-Gesellschaft, Arbeitsgruppe Molekulare und zelluläre Biophysik an der Friedrich-Schiller-Universität Jena, Germany.

J Physiol. 1996 Jun 15;493 ( Pt 3)(Pt 3):625-33. doi: 10.1113/jphysiol.1996.sp021409.

Abstract

The potassium channel beta-subunit from rat brain, Kv beta 1.1, is known to induce inactivation of the delayed rectifier channel Kv1.1 and Kv1.4 delta 1-110. 2. Kv beta 1.1 was co-expressed in Xenopus oocytes with various other potassium channel alpha-subunits. Kv beta 1.1 induced inactivation in members of the Kv1 subfamily with the exception of Kv 1.6; no inactivation of Kv 2.1, Kv 3.4 delta 2-28 and Kv4.1 channels could be observed. 3. The second member of the beta-subunit subfamily, Kv beta 2, had a shorter N-terminal end, accelerated inactivation of the A-type channel Kv 1.4, but did not induce inactivation when co-expressed with delayed rectifiers of the Kv1 channel family. 4. To test whether this subunit co-assembles with Kv alpha-subunits, the N-terminal inactivating domains of Kv beta 1.1 and Kv beta 3 were spliced to the N-terminus of Kv beta 2. The chimaeric beta-subunits (beta 1/ beta 2 and beta 3/ beta 2) induced fast inactivation of several Kv1 channels, indicating that Kv beta 2 associates with these alpha-subunits. No inactivation was induced in Kv 1.3, Kv 1.6, Kv2.1 and Kv3.4 delta 2-28 channels. 5. Kv beta 2 caused a voltage shift in the activation threshold of Kv1.5 of about -10 mV, indicating a putative physiological role. Kv beta 2 had a smaller effect on Kv 1.1 channels. 6. Kv beta 2 accelerated the activation time course of Kv1.5 but had no marked effect on channel deactivation.

摘要

已知大鼠脑钾通道β亚基Kvβ1.1可诱导延迟整流通道Kv1.1和Kv1.4δ1 - 110失活。2. Kvβ1.1与其他多种钾通道α亚基在非洲爪蟾卵母细胞中共表达。Kvβ1.1可诱导Kv1亚家族成员（Kv1.6除外）失活；未观察到Kv2.1、Kv3.4δ2 - 28和Kv4.1通道失活。3. β亚基亚家族的第二个成员Kvβ2的N端较短，可加速A型通道Kv1.4的失活，但与Kv1通道家族的延迟整流器共表达时不诱导失活。4. 为测试该亚基是否与Kvα亚基共组装，将Kvβ1.1和Kvβ3的N端失活结构域拼接到Kvβ2的N端。嵌合β亚基（β1/β2和β3/β2）可诱导几种Kv1通道快速失活，表明Kvβ2与这些α亚基相关联。Kv1.3、Kv1.6、Kv2.1和Kv3.4δ2 - 28通道未诱导失活。5. Kvβ2使Kv1.5的激活阈值发生约 - 10 mV的电压偏移，表明其具有假定的生理作用。Kvβ2对Kv1.1通道的影响较小。6. Kvβ2加速了Kv1.5的激活时间进程，但对通道去激活无明显影响。