Protein Domain : IPR016449

Type:  Family Name:  Potassium channel, inwardly rectifying, Kir
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
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14 Child Features

DB identifier Type Name
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

2 Contains

DB identifier Type Name
IPR013518 Domain Potassium channel, inwardly rectifying, Kir, cytoplasmic
IPR013673 Domain Potassium channel, inwardly rectifying, Kir, N-terminal

4 Cross Referencess

Identifier
PTHR11767
PF01007
PIRSF005465
PR01320

0 Found In

3 GO Annotations

GO Term Gene Name
GO:0005242 IPR016449
GO:0006813 IPR016449
GO:0016021 IPR016449

3 Ontology Annotations

GO Term Gene Name
GO:0005242 IPR016449
GO:0006813 IPR016449
GO:0016021 IPR016449

0 Parent Features

140 Proteins

DB identifier UniProt Accession Secondary Identifier Organism Name Length
2346 D8RQI6 PAC:15409213 Selaginella moellendorffii 404  
123397 D8SRZ6 PAC:15422742 Selaginella moellendorffii 435  
402727 D8QMV2 PAC:15406527 Selaginella moellendorffii 625  
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  
43452 C1N8Z8 PAC:27344704 Micromonas pusilla CCMP1545 634  
197195 PAC:27347370 Micromonas pusilla CCMP1545 685  
39483 C1MR66 PAC:27346486 Micromonas pusilla CCMP1545 758  
85600 C1FH18 PAC:27397312 Micromonas sp RCC299 262  
57469 C1E340 PAC:27398628 Micromonas sp RCC299 2363  
57130 C1E269 PAC:27398580 Micromonas sp RCC299 761  
Cre01.g035800.t1.2 A0A2K3E712 PAC:30789236 Chlamydomonas reinhardtii 574  
Cre13.g591450.t1.2 A0A2K3D141 PAC:30784607 Chlamydomonas reinhardtii 673  
Cre06.g311650.t1.1 A0A2K3DRT3 PAC:30779973 Chlamydomonas reinhardtii 979  
Sphfalx0390s0004.1.p PAC:32626235 Sphagnum fallax 513  
Sphfalx0083s0085.1.p PAC:32620622 Sphagnum fallax 383  
Sphfalx0046s0062.1.p PAC:32619104 Sphagnum fallax 989  
Sphfalx0000s0153.1.p PAC:32613719 Sphagnum fallax 375  
Sphfalx0015s0024.1.p PAC:32600232 Sphagnum fallax 693  
Sphfalx0065s0096.1.p PAC:32601052 Sphagnum fallax 543  
Sphfalx0151s0023.1.p PAC:32630274 Sphagnum fallax 675  
Pp3c15_3810V3.3.p PAC:32926607 Physcomitrium patens 485  
Pp3c15_3810V3.1.p A0A2K1JBS2 PAC:32926608 Physcomitrium patens 476  
Pp3c15_3810V3.2.p PAC:32926606 Physcomitrium patens 485  
Pp3c16_8700V3.2.p A0A2K1J7R0 PAC:32985024 Physcomitrium patens 499  
Pp3c16_8700V3.6.p A0A2K1J7R0 PAC:32985027 Physcomitrium patens 499  
Pp3c16_8700V3.7.p A0A2K1J7R0 PAC:32985028 Physcomitrium patens 499  
Pp3c16_8700V3.3.p A0A2K1J7R0 PAC:32985025 Physcomitrium patens 499  
Pp3c16_8700V3.5.p A0A2K1J7R0 PAC:32985026 Physcomitrium patens 499  

10 Publications

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