Protein Domain : IPR013518

Type:  Domain Name:  Potassium channel, inwardly rectifying, Kir, cytoplasmic
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 broadly separated 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 acid changes 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 or other second messengers []. In eukaryotic cells, K+channels are 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 []. Short Name:  K_chnl_inward-rec_Kir_cyto
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0 Child Features

0 Contains

1 Cross References

Identifier
G3DSA:2.60.40.1400

15 Found Ins

DB identifier Type Name
IPR016449 Family Potassium channel, inwardly rectifying, Kir
IPR003268 Family Potassium channel, inwardly rectifying, Kir1.1
IPR003269 Family Potassium channel, inwardly rectifying, Kir1.2
IPR003270 Family Potassium channel, inwardly rectifying, Kir1.3
IPR003271 Family Potassium channel, inwardly rectifying, Kir2.1
IPR008061 Family Potassium channel, inwardly rectifying, Kir5
IPR008062 Family Inward rectifier potassium channel 13
IPR003272 Family Potassium channel, inwardly rectifying, Kir2.2
IPR003273 Family Potassium channel, inwardly rectifying, Kir2.3
IPR003274 Family Potassium channel, inwardly rectifying, Kir3.1
IPR003275 Family Potassium channel, inwardly rectifying, Kir3.2
IPR003276 Family Potassium channel, inwardly rectifying, Kir3.3
IPR003277 Family Potassium channel, inwardly rectifying, Kir3.4
IPR003278 Family Potassium channel, inwardly rectifying, Kir6.1
IPR003279 Family Potassium channel, inwardly rectifying, Kir6.2

0 GO Annotation

0 Ontology Annotations

1 Parent Features

DB identifier Type Name
IPR014756 Domain Immunoglobulin E-set

247 Proteins

DB identifier UniProt Accession Secondary Identifier Organism Name Length
2346 D8RQI6 PAC:15409213 Selaginella moellendorffii 404  
402727 D8QMV2 PAC:15406527 Selaginella moellendorffii 625  
evm.model.supercontig_19.176 PAC:16411912 Carica papaya 185  
Thhalv10017287m V4MC18 PAC:20180104 Eutrema salsugineum 185  
Lus10014848 PAC:23150149 Linum usitatissimum 102  
Gorai.006G054900.2 A0A0D2Q1C4 PAC:26833012 Gossypium raimondii 150  
Gorai.006G054900.3 A0A0D2RNC2 PAC:26833011 Gossypium raimondii 181  
46533 I0Z6D5 PAC:27390878 Coccomyxa subellipsoidea C-169 627  
42095 I0YXP6 PAC:27392237 Coccomyxa subellipsoidea C-169 302  
55866 I0YUV2 PAC:27385804 Coccomyxa subellipsoidea C-169 673  
197195 PAC:27347370 Micromonas pusilla CCMP1545 685  
47060 C1MQK6 PAC:27346610 Micromonas pusilla CCMP1545 441  
109015 C1FIG5 PAC:27397551 Micromonas sp RCC299 440  
85600 C1FH18 PAC:27397312 Micromonas sp RCC299 262  
59832 C1E9T4 PAC:27404509 Micromonas sp RCC299 417  
63532 C1EG70 PAC:27402850 Micromonas sp RCC299 442  
109570 PAC:27400818 Micromonas sp RCC299 384  
Thecc1EG012901t2 A0A061FWX6 PAC:27446726 Theobroma cacao 173  
Thecc1EG012901t1 A0A061FVU9 PAC:27446725 Theobroma cacao 202  
Cagra.0003s0042.1.p PAC:28913308 Capsella grandiflora 185  
Cagra.0501s0005.1.p PAC:28903886 Capsella grandiflora 64  
Brara.D02428.1.p A0A397ZSG0 PAC:30622241 Brassica rapa FPsc 184  
Bostr.22157s0108.1.p PAC:30653823 Boechera stricta 72  
Cre01.g035800.t1.2 A0A2K3E712 PAC:30789236 Chlamydomonas reinhardtii 574  
Cre10.g417750.t1.1 A0A2K3D8Y0 PAC:30790264 Chlamydomonas reinhardtii 371  
Cre13.g591450.t1.2 A0A2K3D141 PAC:30784607 Chlamydomonas reinhardtii 673  
Cre06.g311650.t1.1 A0A2K3DRT3 PAC:30779973 Chlamydomonas reinhardtii 979  
Bradi4g38222.1.p PAC:31143709 Brachypodium distachyon 317  
Pahal.G01132.2 PAC:32520891 Panicum hallii 162  
Sphfalx0390s0004.1.p PAC:32626235 Sphagnum fallax 513  

10 Publications

First Author Title Year Journal Volume Pages PubMed ID
            1772658
            1879548
            1373731
            2448635
            2451788
            2555158
            11178249
            7580148
            10102275
            10449331