Novel gating mechanism of polyamine block in the strong inward rectifier K channel Kir2.1

Inward rectifying potassium channels are needed for sustaining resting membrane potential and modulating excitability in many cell types. Interactions between polyamines and the polyamine toxins philanthotoxin and argiotoxin on inward rectification of the strong inward rectifier Kir2.1 were investigated. Results revealed that high affinity polyamine block is not related to direct open channel block. Instead, it requires polyamines binding to another region of the channel to produce a blocking complex that occludes the pore.