Molecular mechanisms of ion conduction and ion selectivity in TMEM16 lipid scramblases

Ion conduction and selectivity in acid-sensing ion channel 1

The ability of acid-sensing ion channels (ASICs) to discriminate among cations was assessed based on changes in conductance and reversal potential with ion substitution. Human ASIC1a was expressed in Xenopus laevis oocytes, and acid-induced currents were measured using two-electrode voltage clamp. Replacement of extracellular Na(+) with Li(+), K(+), Rb(+), or Cs(+) altered inward conductance an...

Ion conduction and selectivity in K(+) channels.

Potassium (K(+)) channels are tetrameric membrane-spanning proteins that provide a selective pore for the conductance of K(+) across the cell membranes. These channels are most remarkable in their ability to discriminate K(+) from Na(+) by more than a thousandfold and conduct at a throughput rate near diffusion limit. The recent progress in the structural characterization of K(+) channel provid...

Ion Conduction and Selectivity in K+ Channels

Ion conduction and selectivity in the ryanodine receptor channel.

The ryanodine receptor channel is an intracellular membrane Ca2+-release channel. The investigation of ion translocation and discrimination in individual channels under voltage-clamp conditions has revealed that the channel can sustain very high rates of cation translocation, has high affinity for divalent cations and displays relatively poor discrimination between physiologically relevant cati...

Multi-ion versus single-ion conduction mechanisms can yield current rectification in biological ion channels.

There is clear evidence that the net magnitude of negative charge at the intracellular end of inwardly rectifying potassium channels helps to generate an asymmetry in the magnitude of the current that will pass in each direction. However, a complete understanding of the physical mechanism that links these charges to current rectification has yet to be obtained. Using Brownian dynamics, we compa...