The importance of charge compensation in the membrane
In this post I continue my series on the omega current by discussing how a mutation that removes a charged group from the voltage-sensor domain (VSD) would be highly destabilizing and disruptive. The omega current is a leak current that passes through the VSD of mutated voltage-gated cation channels. In some cases, the mutated channels … Read more
Omega Current Channelopathies
In this post I will be continuing my series on the omega current. The omega current is a leak current that passes through the voltage-sensor domain (VSD) of mutated voltage-gated cation channels. Mutation of the VSD S4 helix can reveal a cryptic pore that allows ions (H+, Li+, K+, Rb+ and even guanidinium) to cross … Read more
Pores and Selectivity Filters
In this post I will be briefly introducing the classical ideas of ion conduction through membrane proteins. The idea of ion channels as selective pores in the cell membrane is very old but is now understood at atomic detail. So what is a channel? What does an ion conductive pore look like? Here, I will … Read more
Human Hv1: Architectural Overview
Although voltage-gated proton currents have been measured in cell membranes since the early 1980s (Tomas & Meech, 1982), the genes encoding the voltage-gated proton channels were not discovered until 2006 (Sasaki et al., 2006; Ramsey et al., 2006). What the gene sequence demonstrated was that Hv channels share sequence homology with the voltage-sensor domains (VSDs) of … Read more
