Plasticity of gating in pore-only potassium channels

Abstract

Most potassium (K+) channels have two main gates: one at the cytosolic pore entrance (inner gate) and one at the level of the selectivity filter (filter gate). In many channels the inner gate serves as the activation gate. This means that the opening of this gate can be modulated by an external stimulus (e.g. a change in membrane potential or pH). After opening of the inner gate some K+ channels such as Kv1.3 or KcsA undergo a subsequent inactivation, which is caused by conformational rearrangements inside the selectivity filter.