Patch-clamp technique is a powerful method for studying mitochondrial ion transport in real time and under native conditions. This article discusses the limitations of different methodologies, advent of mitoplast patch-clamp technique, and how it presents an exciting opportunity for exploring the molecular physiology of mitochondrial ion transporters.
Kopec et al. show that filter gating in the MthK potassium channel and the pore-helix mutant V55E is associated with widening of the selectivity filter and is modulated by specific interactions between filter and pore-helix residues.
Sodium channel subpopulations with distinct biophysical properties and subcellular localization enhance cardiac conduction
Sodium channels are organized in multiple pools with distinct biophysical properties and subcellular localization, but the role of these subpopulations is not well understood. Computational modeling predicts that intercalated disk-localized sodium channels with shifted steady-state activation and inactivation voltage dependence promote faster cardiac conduction.
The urea transporter UT-B in human red blood cells has been claimed to transport water too. In this study, Brahm et al. show donor variation in urea but not water transport, and a different inhibition pattern for urea and water transport. The authors contest a common pathway for both solutes.
Dantrolene, an inhibitor of the cardiac calcium release channel (RyR2), is a lead compound for stabilizing overactive RyR2 in heart failure. We find that dantrolene inhibition requires RyR2 association with FKBP12.6, which in turn depends on RyR2 phosphorylation at S2808.