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 … Continue reading
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 … Continue reading
The Omega Current
Mutation of voltage-sensor domains (VSDs) can sometimes lead to ions leaking across the membrane through the VSDs themselves. Ion conduction through the mutated VSD of the Shaker Kv channel was coined the “omega current” by Tombola, Pathak and Isacoff (Tombola et al., 2005). Many different mutations have been identified that result in current leaking through the VSDs of … Continue reading
The Problem of Aligning S4
Recently, a number of papers have come out that have used sequence homology to generate structural models of human Hv1 (Musset et al,. 2010; Ramsey et al., 2010; Wood et al., 2012). These models have then been used for docking and molecular-dynamics simulations to try to extract some mechanistic insight into the channel function. In … Continue reading
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