Potassium channel (plasma membrane type) (K⁺ channel)

Plasma membrane potassium channels are integral transmembrane proteins that selectively permit the passage of potassium ions across cell membranes, playing a central role in maintaining resting membrane potential and shaping action potentials in excitable tissues such as nerves and muscles. They exist as tetramers forming a central pore lined by selectivity filters that ensure high specificity for K⁺ over other ions like Na⁺—a property critical for proper electrical signaling. Over 80 different human genes encode various types, including voltage-gated, inwardly rectifying, calcium-, pH-, ATP-, or ligand-regulated forms. Their function underpins processes ranging from neuronal firing and muscle contraction to hormone secretion and immune cell activation. Dysfunction or inappropriate modulation can lead to diseases including arrhythmias, epilepsy, ataxia, diabetes mellitus type II, neurodegeneration—and they are important drug targets both therapeutically and toxically.

Other names

Potassium channelK⁺ channelVoltage-gated potassium channel (Kv)Inwardly rectifying potassium channel (Kir)Calcium-activated potassium channel (KCa)ATP-sensitive potassium channel (KATP)

Drugs may: Block the pore to inhibit K⁺ flow (“channel blockers” like amiodarone or peptide toxins); Open/activate the pore to increase conductance (“channel openers” such as minoxidil for some types); Modulate gating by binding regulatory domains.