Wang S, Morales M J, Liu S, Strauss H C, Rasmusson R L
Department of Medicine, Duke University Medical Center, Durham, NC 27708-0281, USA.
FEBS Lett. 1996 Jul 1;389(2):167-73. doi: 10.1016/0014-5793(96)00570-4.
The rapid delayed rectifier, IKr, is believed to have h-erg (human ether-à-go-go related gene) as its molecular basis. A recent study has shown that rectification of h-erg involves a rapid inactivation process that involves rapid closure of the external mouth of the pore or C-type inactivation. We measured the instantaneous current to voltage relationship for h-erg channels using the saponin permeabilized variation of the cut-open oocyte clamp technique. In contrast to C-type inactivation in other voltage-gated K+ channels, the rate of inactivation was strongly voltage dependent at depolarized potentials. This voltage dependence could be modulated independently of activation by increasing [K+]0 from 2 to 98 mM. These results suggest that inactivation of h-erg has its own intrinsic voltage sensor.
快速延迟整流钾电流（IKr）被认为是以人类醚 - 去极化相关基因（h-erg）作为其分子基础。最近的一项研究表明，h-erg的整流涉及一个快速失活过程，该过程涉及孔道外部开口的快速关闭或C型失活。我们使用皂素通透化的切开卵母细胞钳技术变体测量了h-erg通道的瞬时电流 - 电压关系。与其他电压门控钾通道中的C型失活不同，失活速率在去极化电位下强烈依赖于电压。通过将[K + ]0从2 mM增加到98 mM，可以独立于激活来调节这种电压依赖性。这些结果表明，h-erg的失活有其自身内在的电压传感器。
