InterPro : IPR013518

Name  Potassium channel, inwardly rectifying, Kir, cytoplasmic Short Name  K_chnl_inward-rec_Kir_cyto
Type  Domain Description  Potassium channels are the most diverse group of the ion channel family[, ]. They are important in shaping the action potential, and in neuronal excitability and plasticity []. The potassium channel family iscomposed of several functionally distinct isoforms, which can be broadlyseparated into 2 groups []: the practically non-inactivating 'delayed' group and the rapidly inactivating 'transient' group.These are all highly similar proteins, with only small amino acidchanges causing the diversity of the voltage-dependent gating mechanism,channel conductance and toxin binding properties. Each type of K+channel is activated by different signals and conditions depending on their type of regulation: some open in response to depolarisation of the plasma membrane; others in response to hyperpolarisation or an increase in intracellular calcium concentration; some can be regulated by binding of a transmitter, together with intracellular kinases; while others are regulated by GTP-binding proteins orother second messengers []. In eukaryotic cells, K+channelsare involved in neural signalling and generation of the cardiac rhythm, act as effectors in signal transduction pathways involving G protein-coupled receptors (GPCRs) and may have a role in target cell lysis by cytotoxic T-lymphocytes []. In prokaryotic cells, they play a role in themaintenance of ionic homeostasis [].All K+channels discovered so far possess a core of alpha subunits, each comprising either one or two copies of a highly conserved pore loop domain (P-domain). The P-domain contains the sequence (T/SxxTxGxG), which hasbeen termed the K+selectivity sequence.In families that contain one P-domain, four subunits assemble to form a selective pathway for K+across the membrane.However, it remains unclear how the 2 P-domain subunits assemble to form a selective pore. The functional diversity of these families can arise through homo- or hetero-associations of alpha subunits or association with auxiliary cytoplasmic beta subunits. K+channel subunits containing one pore domain can be assigned into one of two superfamilies: those that possess six transmembrane (TM) domains and those that possess only two TM domains.The six TM domain superfamily can be further subdivided into conserved gene families: the voltage-gated (Kv) channels; the KCNQ channels (originally known as KvLQT channels); the EAG-like K+channels; and three types of calcium (Ca)-activated K+channels (BK, IK and SK)[]. The 2TM domain family comprises inward-rectifying K+channels. In addition, there are K+channel alpha-subunits that possess two P-domains. These are usually highly regulated K+selective leak channels.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 []. 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 [, ].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. Thus, Kir channels share similarity with the fifth and sixth domains, and P-domain of the other families. It is thought that four Kir subunits assemble to form a tetrameric channel complex, which may be hetero- or homomeric [].

Sequence Features

GO Displayer


InterPro protein domain ID --> Contigs



0 Child Features

0 Contains

15 Found In

Id Name Short Name Type
IPR016449 Potassium channel, inwardly rectifying, Kir K_chnl_inward-rec_Kir Family
IPR003270 Potassium channel, inwardly rectifying, Kir1.3 K_chnl_inward-rec_Kir1.3 Family
IPR003271 Potassium channel, inwardly rectifying, Kir2.1 K_chnl_inward-rec_Kir2.1 Family
IPR003272 Potassium channel, inwardly rectifying, Kir2.2 K_chnl_inward-rec_Kir2.2 Family
IPR003273 Potassium channel, inwardly rectifying, Kir2.3 K_chnl_inward-rec_Kir2.3 Family
IPR003274 Potassium channel, inwardly rectifying, Kir3.1 K_chnl_inward-rec_Kir3.1 Family
IPR003275 Potassium channel, inwardly rectifying, Kir3.2 K_chnl_inward-rec_Kir3.2 Family
IPR003276 Potassium channel, inwardly rectifying, Kir3.3 K_chnl_inward-rec_Kir3.3 Family
IPR003277 Potassium channel, inwardly rectifying, Kir3.4 K_chnl_inward-rec_Kir3.4 Family
IPR003278 Potassium channel, inwardly rectifying, Kir6.1 K_chnl_inward-rec_Kir6.1 Family
IPR003279 Potassium channel, inwardly rectifying, Kir6.2 K_chnl_inward-rec_Kir6.2 Family
IPR008061 Potassium channel, inwardly rectifying, Kir5 K_chnl_inward-rec_Kir5 Family
IPR008062 Inward rectifier potassium channel 13 KCNJ13 Family
IPR003268 Potassium channel, inwardly rectifying, Kir1.1 K_chnl_inward-rec_Kir1.1 Family
IPR003269 Potassium channel, inwardly rectifying, Kir1.2 K_chnl_inward-rec_Kir1.2 Family

1 Parent Features

Id Name Short Name Type
IPR014756 Immunoglobulin E-set Ig_E-set Domain

10 Publications

First Author Title Year Journal Volume Pages
Perney TM The molecular biology of K+ channels. 1991 Curr Opin Cell Biol 3 663-70
Luneau C Shaw-like rat brain potassium channel cDNA's with divergent 3' ends. 1991 FEBS Lett 288 163-7
Attali B Cloning, functional expression, and regulation of two K+ channels in human T lymphocytes. 1992 J Biol Chem 267 8650-7
Schwarz TL Multiple potassium-channel components are produced by alternative splicing at the Shaker locus in Drosophila. 1988 Nature 331 137-42
Tempel BL Cloning of a probable potassium channel gene from mouse brain. 1988 Nature 332 837-9
Stühmer W Molecular basis of functional diversity of voltage-gated potassium channels in mammalian brain. 1989 EMBO J 8 3235-44
Miller C An overview of the potassium channel family. 2000 Genome Biol 1 REVIEWS0004
Doupnik CA The inward rectifier potassium channel family. 1995 Curr Opin Neurobiol 5 268-77
Minor DL Jr Transmembrane structure of an inwardly rectifying potassium channel. 1999 Cell 96 879-91
Reimann F Inwardly rectifying potassium channels. 1999 Curr Opin Cell Biol 11 503-8

To cite PlanMine, please refer to the following publication:

Rozanski, A., Moon, H., Brandl, H., Martín-Durán, J. M., Grohme, M., Hüttner, K., Bartscherer, K., Henry, I., & Rink, J. C.
PlanMine 3.0—improvements to a mineable resource of flatworm biology and biodiversity
Nucleic Acids Research, gky1070. doi:10.1093/nar/gky1070 (2018)