Peculiarities of mitochondrial chloride channel kinetics.

Abstract

Cardiac mitochondrial chloride channels are involved in the regulation of mitochondrial membrane potential, with impact on the sarcolemma action potential. Despite their importance, they still lack molecular identity. So far, the most probable hypothesis is that they are part of the CLIC channel family. Here, we report a detailed profile of these channels under different conditions. We find this characterization essential for their identification and comparison with other chloride channels. The presence of many unresolved closed events at higher acquisition rate and extremely long closings were detected, which was consistent with the power-law distribution. On the other hand, the channel openings were described by a single-exponential function. We compare the results with ion channels of similar dwell time distribution and discuss the possible connections to other chloride channels and channel families, including the CLIC family. Moreover, the described kinetic features call for theoretical interpretation and proper single-channel analysis.