Selective proton permeability and pH regulation of the influenza virus M2 channel expressed in mouse erythroleukaemia cells
Selective proton permeability and pH regulation of the influenza virus M2 channel expressed in mouse erythroleukaemia cells
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DOI：
10.1113/jphysiol.1996.sp021495
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发表时间：
1996-07-15
影响因子：
5.5
通讯作者：
Hay, AJ
中科院分区：
文献类型：
--
作者：
Chizhmakov, IV;Geraghty, FM;Hay, AJ
1. 甲型流感病毒的M2蛋白在感染过程中涉及跨膜pH调节。对表面膜上表达M2蛋白的小鼠红白血病细胞进行全细胞膜片钳实验，结果显示由M2引起的电导可被抗流感药物金刚乙胺特异性阻断。
2. 确定了通过M2的金刚乙胺敏感电流的离子选择性。反转电位接近跨膜pH梯度的平衡电位，而不是Na⁺、K⁺或Cl⁻浓度梯度的平衡电位。估计M2对Na⁺相对于H⁺的通透性小于6×10⁻⁷。
3. 当外部pH降至8.5以下时，M2电导增加，并在外部pH为4时接近饱和，这是由于驱动电位增加导致通透性增加以及低外部pH激活所致。在生理条件下，激活和渗透都可以通过质子与M2上的位点相互作用来描述，其表观解离常数分别约为0.1μM和1μM。
4. M2蛋白能够随着H⁺电化学梯度选择性地跨膜转运质子，这些特性与其在病毒感染期间改变病毒粒子和反式高尔基体pH的作用一致。
1. The M2 protein of influenza A virus is implicated in transmembrane pH regulation during infection. Whole-cell patch clamp of mouse erythroleukaemia cells expressing the M2 protein in the surface membrane showed a conductance due to M2 which was specifically blocked by the anti-influenza drug rimantadine.2. The ion selectivity of the rimantadine-sensitive current through M2 was determined. Reversal potentials were close to equilibrium potentials for transmembrane pH gradients and not to those for Na+, K+ or Cl- concentration gradients. M2 permeability to Na+ relative to H+ was estimated to be less than 6 x 10(-7).3. The M2 conductance increased as external pH decreased below 8.5 and approached saturation at an external pH of 4, effects attributable to increased permeability due to increased driving potential and to activation by low external pH. Both activation and permeation could be described by interaction of protons with sites on M2, with apparent dissociation constants of approximately 0.1 mu M and 1 mu M, respectively, under physiological conditions.4. The M2 protein can transfer protons selectively across membranes with the H+ electrochemical gradient, properties consistent with its role in modifying virion and trans-Golgi pH during virus infection.