Protein Domain : IPR005404

Type:  Family Name:  Potassium channel, voltage dependent, Kv3.3
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.The Kv family can be divided into several subfamilies on the basis of sequence similarity and function. Four of these subfamilies, Kv1 (Shaker), Kv2 (Shab), Kv3 (Shaw) and Kv4 (Shal), consist of pore-forming alpha subunits that associate with different types of beta subunit. Each alpha subunit comprises six hydrophobic TM domains with a P-domain between the fifth and sixth, which partially resides in the membrane. The fourth TM domain has positively charged residues at every third residue and acts as a voltage sensor, which triggers the conformational change that opens the channel pore in response to a displacement in membrane potential []. More recently, 4 new electrically-silent alpha subunits have been cloned: Kv5 (KCNF), Kv6 (KCNG), Kv8 and Kv9 (KCNS). These subunits do not themselves possess any functional activity, but appear to form heteromeric channels with Kv2 subunits, and thus modulate Shab channel activity []. When highly expressed, they inhibit channel activity, but at lower levels show more specific modulatory actions.A voltage-dependent potassium channel gene designated Shaw was initially isolated from Drosophila melanogaster(Fruit fly). Subsequently, several vetebrate potassium channels with similar amino acid sequences were subsequently found and, together with the D. melanogaster channel, now constitute the Kv3 family. These channels are thought to play a role in shortening of action potential durations and modulating pre-synaptic neurotransmitter release. In mammals, the family consists of 4 genes (Kv3.1, Kv3.2, Kv3.3 and Kv3.4). Each gene product has its own subcellular location and function.Kv3.3 channels are evenly distributed over the soma and proximal apical dendrites. They have also been found in the lens epithelium, corneal endothelium, cerebellar cells and the deep cerebellar nuclei. When co-expressed with NADPH oxidase, they function as an oxygen sensor complex in airway chemoreceptors. Short Name:  K_chnl_volt-dep_Kv3.3
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0 Child Features

4 Contains

DB identifier Type Name
IPR005821 Domain Ion transport domain
IPR011333 Domain POZ domain
IPR000210 Domain BTB/POZ domain
IPR003131 Domain Potassium channel tetramerisation-type BTB domain

1 Cross References

Identifier
PR01582

0 Found In

3 GO Annotations

GO Term Gene Name
GO:0005249 IPR005404
GO:0006813 IPR005404
GO:0016021 IPR005404

3 Ontology Annotations

GO Term Gene Name
GO:0005249 IPR005404
GO:0006813 IPR005404
GO:0016021 IPR005404

1 Parent Features

DB identifier Type Name
IPR003974 Family Potassium channel, voltage dependent, Kv3

10 Proteins

DB identifier UniProt Accession Secondary Identifier Organism Name Length
Cre02.g081700.t1.1 A0A2K3E0K4 PAC:30785765 Chlamydomonas reinhardtii 588  
Cre06.g308650.t1.1 A0A2K3DRI4 PAC:30779830 Chlamydomonas reinhardtii 940  
Pum0047s0015.1.p A0A1X6PII8 PAC:38009206 Porphyra umbilicalis 383  
Pum0261s0002.1.p A0A1X6P207 PAC:38014352 Porphyra umbilicalis 670  
Pum0205s0016.1.p A0A1X6P5H5 PAC:38006311 Porphyra umbilicalis 797  
Pum0146s0007.1.p A0A1X6P9U3 PAC:38006094 Porphyra umbilicalis 1212  
Pum0014s0072.1.p A0A1X6PL35 PAC:38015910 Porphyra umbilicalis 878  
Pum0187s0005.1.p A0A1X6P6Y1 PAC:38006565 Porphyra umbilicalis 872  
Pum0065s0020.1.p A0A1X6PGW8 PAC:38012762 Porphyra umbilicalis 462  
Vocar.0047s0038.1.p PAC:32899330 Volvox carteri 840  

9 Publications

First Author Title Year Journal Volume Pages PubMed ID
            1772658
            1879548
            1373731
            2448635
            2451788
            2555158
            11178249
            9305895
            10712896