Tytgat J, Nakazawa K, Gross A, Hess P
Department of Cellular and Molecular Physiology, Harvard Medical School, Boston, Massachusetts 02115.
J Biol Chem. 1993 Nov 15;268(32):23777-9.
Ion channels are generally classified as voltage- or ligand-gated channels based upon their ability to respond to a change in the transmembrane voltage or to a specific ligand interaction. The voltage sensor of voltage-gated ion channels is thought to be contained within the fourth putative transmembrane segment, S4, and is characterized by basic residues typically spaced apart. Thus far, a full understanding of all charges contributing to the voltage sensor of voltage-gated potassium channels has been lacking since several neutralization mutants in S4 could not be functionally expressed. By construction of multimeric cDNAs encoding a mammalian RCK1 (Kv1.1) potassium channel, we now report functional expression of all charge neutralizations in the S4 segment, providing a more comprehensive insight into the functioning of the voltage sensor.
离子通道通常根据其对跨膜电压变化或特定配体相互作用的响应能力分为电压门控通道或配体门控通道。电压门控离子通道的电压传感器被认为包含在第四个假定的跨膜片段S4中，其特征是通常间隔排列的碱性残基。到目前为止，由于S4中的几个中和突变体无法进行功能表达，因此尚未完全了解对电压门控钾通道电压传感器有贡献的所有电荷。通过构建编码哺乳动物RCK1（Kv1.1）钾通道的多聚体cDNA，我们现在报告了S4片段中所有电荷中和的功能表达，从而对电压传感器的功能有了更全面的了解。
