2018
Volume 18, Number 3, pp. 121–124
Molecular mechanism of ion channel inactivation in model and cell membranes
P.A. Grigoriev and M.G. Sharapov
Institute of Cell Biophysics, Russian Academy of Sciences, 142290 Pushchino, Moscow Region, Russia
Properties of the cation-selective ion channels formed by peroxiredoxin-2 and peroxiredoxin-6 are studied and compared with those of excitable cell membranes. It is shown that the peroxiredoxins form ion channel clusters whose conductance is inactivated by the current passing through them. The characteristic discrete decrease of the conductance is explained by proposing that the cluster is a structure containing up to 12 peroxiredoxin decamers, each forming a cation-selective ion channel and that the total conductance of the cluster is inactivated by the thermal energy generated by the electrical current passing through the channels. The recorded density of the current required for inactivation is about 10-8 A/μm2. Literature data for inactivation of the sodium ion clusters in the Ranvier junctions of the neuron has been reviewed and the same amplitude current densities are found there. On the basis of the discovered correlation it is proposed that the molecular mechanism of (thermal) inactivation is the same in both of these ion-conducting protein structures.
Keywords: inactivation, ion channel clusters, molecular mechanism, peroxiredoxins