Potassium channel, inwardly rectifying, transmembrane domain (IPR040445)

Short name: Kir_TM

Overlapping homologous superfamilies


Domain relationships



Inwardly-rectifying potassium channels (Kir) are the principal class of two-TM domain potassium channels. They are characterised by the property of inward-rectification, which is described as the ability to allow large inward currents and smaller outward currents. Inwardly rectifying potassium channels (Kir) are responsible for regulating diverse processes including: cellular excitability, vascular tone, heart rate, renal salt flow, and insulin release [PMID: 10102275]. To date, around twenty members of this superfamily have been cloned, which can be grouped into six families by sequence similarity, and these are designated Kir1.x-6.x [PMID: 7580148, PMID: 10449331].

Cloned Kir channel cDNAs encode proteins of between ~370-500 residues, both N- and C-termini are thought to be cytoplasmic, and the N terminus lacks a signal sequence. Kir channel alpha subunits possess only 2TM domains linked with a P-domain. The two 'transmembrane passes' place the C-terminal tail on the cytoplasmic side of the membrane [PMID: 7580148]. It is thought that four Kir subunits assemble to form a tetrameric channel complex, which may be hetero- or homomeric [PMID: 10102275].

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.