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Protein Domain : 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 [].

Publication Counts Displayer

0 Child Features

0 Contains

1 Cross References

Source . Name

Subject . Primary Identifier

2 Data Sets

Name URL
TrEMBL data set
InterPro data set  

15 Found In

DB identifier Name Short Name Type
IPR016449 Potassium channel, inwardly rectifying, Kir K_chnl_inward-rec_Kir 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
IPR003279 Potassium channel, inwardly rectifying, Kir6.2 K_chnl_inward-rec_Kir6.2 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
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
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
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
IPR003270 Potassium channel, inwardly rectifying, Kir1.3 K_chnl_inward-rec_Kir1.3 Family
IPR008061 Potassium channel, inwardly rectifying, Kir5 K_chnl_inward-rec_Kir5 Family
IPR008062 Inward rectifier potassium channel 13 KCNJ13 Family

0 GO Annotation

0 Ontology Annotations

1 Parent Features

DB identifier Name Short Name Type
IPR014756 Immunoglobulin E-set Ig_E-set Domain

48 Proteins

DB identifier Primary Accession
Organism . Name
FBpp0083817 Q9VCL9 Drosophila melanogaster
FBpp0083818 Q8IMY7 Drosophila melanogaster
FBpp0080669 Q9VJ56 Drosophila melanogaster
FBpp0309813 B7YZX2 Drosophila melanogaster
FBpp0307576 A8JR87 Drosophila melanogaster
FBpp0307579 E1JIU2 Drosophila melanogaster
FBpp0307578 Q9VCQ0 Drosophila melanogaster
FBpp0291073 E1JIU5 Drosophila melanogaster
FBpp0279039 Q29LD8 Drosophila pseudoobscura
FBpp0282331 Q29A55 Drosophila pseudoobscura
FBpp0282804 Q29BQ4 Drosophila pseudoobscura
FBpp0292183 I5ANI3 Drosophila pseudoobscura
FBpp0292182 I5ANI2 Drosophila pseudoobscura
FBpp0293301 I5AN03 Drosophila pseudoobscura
FBpp0293302 I5AN02 Drosophila pseudoobscura
FBpp0159925 B4KAL4 Drosophila mojavensis
FBpp0166068 B4KG98 Drosophila mojavensis
FBpp0171479 B4K775 Drosophila mojavensis
FBpp0231617 B4LTS0 Drosophila virilis
FBpp0237540 B4M0R8 Drosophila virilis
FBpp0238470 B4M086 Drosophila virilis
FBpp0255370 B4PN54 Drosophila yakuba
FBpp0257721 B4P9X5 Drosophila yakuba
FBpp0268963 B4PN90 Drosophila yakuba
A8X5V6_CAEBR A8X5V6 Caenorhabditis briggsae
A8XBI7_CAEBR A8XBI7 Caenorhabditis briggsae
A8XC74_CAEBR A8XC74 Caenorhabditis briggsae
K7GYC0_CAEJA K7GYC0 Caenorhabditis japonica
K7H4M9_CAEJA K7H4M9 Caenorhabditis japonica
H2VI59_CAEJA H2VI59 Caenorhabditis japonica