Potassium channels are the most diverse group of the ion channel family [[cite:PUB00001055], [cite:PUB00001622]]. They are important in shaping the action potential, and in neuronal excitability and plasticity [[cite:PUB00004020]]. The potassium channel family is composed of several functionally distinct isoforms, which can be broadly separated into 2 groups [[cite:PUB00006577]]: the practically non-inactivating 'delayed' group and the rapidly inactivating 'transient' group.
\r\nThese 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 [[cite:PUB00004011]]. 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 [[cite:PUB00002771]]. In prokaryotic cells, they play a role in the maintenance of ionic homeostasis [[cite:PUB00009378]].
\r\nAll 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 has been 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) [[cite:PUB00009378]]. 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.
"", 'llm': False, 'checked': False, 'updated': False}, {'text': 'The first EAG K+ channel was identified in Drosophila melanogaster (Fruit fly), following a screening for mutations giving rise to behavioural abnormalities. Disruption of the Eag gene caused an ether-induced, leg-shaking behaviour. Subsequent studies have revealed a conserved multi-gene family of EAG-like K+ channels, which are present in human and many other species. Based on the varying functional properties of the channels, the family has been divided into 3 subfamilies: EAG, ELK and ERG. Interestingly, Caenorhabditis elegans appears to lack the ELK type [[cite:PUB00007312]].
', 'llm': False, 'checked': False, 'updated': False}, {'text': 'The human ether-a-go-go-related gene (HERG), cloned from hippocampus, shares 49% amino acid identity with EAG. It is also found in the heart, where it helps to control K+ efflux [[cite:PUB00008904]]. Mutations in HERG result in the disruption of the repolarising current and the disease LQT2 syndrome, an inherited disorder of cardiac repolarisation that predisposes affected individuals to life-threatening arrhythmias [[cite:PUB00008906]].
', 'llm': False, 'checked': False, 'updated': False}, {'text': ""This entry also includes the nematode homologue Potassium voltage-gated channel unc-103 from Caenorhabditis elegans which is involved in the movements of the male's copulatory spicules before and during male mating behaviour [[cite:PUB00155000]].
"", 'llm': False, 'checked': False, 'updated': False}]" "" "[{'identifier': 'GO:0005249', 'name': 'voltage-gated potassium channel activity', 'category': {'code': 'F', 'name': 'molecular_function'}}, {'identifier': 'GO:0006813', 'name': 'potassium ion transport', 'category': {'code': 'P', 'name': 'biological_process'}}, {'identifier': 'GO:0016020', 'name': 'membrane', 'category': {'code': 'C', 'name': 'cellular_component'}}]" "{'accession': 'IPR003938', 'name': 'Potassium channel, voltage-dependent, EAG/ELK/ERG-like', 'type': 'Family', 'children': [{'accession': 'IPR045319', 'name': 'Potassium channel KAT/AKT', 'type': 'Family', 'children': []}, {'accession': 'IPR050818', 'name': 'Potassium channel, voltage-dependent, EAG/ELK/ERG-like, animal-type', 'type': 'Family', 'children': [{'accession': 'IPR003949', 'name': 'Potassium channel, voltage-dependent, EAG', 'type': 'Family', 'children': []}, {'accession': 'IPR003950', 'name': 'Potassium channel, voltage-dependent, ELK', 'type': 'Family', 'children': []}, {'accession': 'IPR003967', 'name': 'Potassium channel, voltage-dependent, ERG', 'type': 'Family', 'children': []}]}]}" "" False False False "{'PUB00007312': {'PMID': 10798390, 'ISBN': None, 'volume': '26', 'issue': '1', 'year': 2000, 'title': 'Ion channels and synaptic organization: analysis of the Drosophila genome.', 'URL': None, 'raw_pages': '35-43', 'medline_journal': 'Neuron', 'ISO_journal': 'Neuron', 'authors': ['Littleton JT', 'Ganetzky B.'], 'DOI_URL': 'http://dx.doi.org/10.1016/S0896-6273(00)81135-6'}, 'PUB00009378': {'PMID': 11178249, 'ISBN': None, 'volume': '1', 'issue': '4', 'year': 2000, 'title': 'An overview of the potassium channel family.', 'URL': None, 'raw_pages': 'REVIEWS0004', 'medline_journal': 'Genome Biol', 'ISO_journal': 'Genome Biol.', 'authors': ['Miller C.'], 'DOI_URL': 'http://ukpmc.ac.uk/picrender.cgi?tool=EBI&pubmedid=11178249&action=stream&blobtype=pdf'}, 'PUB00001622': {'PMID': 1879548, 'ISBN': None, 'volume': '288', 'issue': '1-2', 'year': 1991, 'title': ""Shaw-like rat brain potassium channel cDNA's with divergent 3' ends."", 'URL': None, 'raw_pages': '163-7', 'medline_journal': 'FEBS Lett', 'ISO_journal': 'FEBS Lett.', 'authors': ['Luneau C', 'Wiedmann R', 'Smith JS', 'Williams JB.'], 'DOI_URL': 'http://dx.doi.org/10.1016/0014-5793(91)81026-5'}, 'PUB00006577': {'PMID': 2555158, 'ISBN': None, 'volume': '8', 'issue': '11', 'year': 1989, 'title': 'Molecular basis of functional diversity of voltage-gated potassium channels in mammalian brain.', 'URL': None, 'raw_pages': '3235-44', 'medline_journal': 'EMBO J', 'ISO_journal': 'EMBO J.', 'authors': ['Stuhmer W', 'Ruppersberg JP', 'Schroter KH', 'Sakmann B', 'Stocker M', 'Giese KP', 'Perschke A', 'Baumann A', 'Pongs O.'], 'DOI_URL': 'http://ukpmc.ac.uk/articlerender.cgi?tool=EBI&pubmedid=2555158'}, 'PUB00002771': {'PMID': 1373731, 'ISBN': None, 'volume': '267', 'issue': '12', 'year': 1992, 'title': 'Cloning, functional expression, and regulation of two K+ channels in human T lymphocytes.', 'URL': None, 'raw_pages': '8650-7', 'medline_journal': 'J Biol Chem', 'ISO_journal': 'J. Biol. Chem.', 'authors': ['Attali B', 'Romey G', 'Honore E', 'Schmid-Alliana A', 'Mattei MG', 'Lesage F', 'Ricard P', 'Barhanin J', 'Lazdunski M.'], 'DOI_URL': 'http://intl.jbc.org/cgi/content/abstract/267/12/8650'}, 'PUB00008906': {'PMID': 10187793, 'ISBN': None, 'volume': '274', 'issue': '15', 'year': 1999, 'title': 'Long QT syndrome-associated mutations in the Per-Arnt-Sim (PAS) domain of HERG potassium channels accelerate channel deactivation.', 'URL': None, 'raw_pages': '10113-8', 'medline_journal': 'J Biol Chem', 'ISO_journal': 'J. Biol. Chem.', 'authors': ['Chen J', 'Zou A', 'Splawski I', 'Keating MT', 'Sanguinetti MC.'], 'DOI_URL': 'http://dx.doi.org/10.1074/jbc.274.15.10113'}, 'PUB00004020': {'PMID': 2451788, 'ISBN': None, 'volume': '332', 'issue': '6167', 'year': 1988, 'title': 'Cloning of a probable potassium channel gene from mouse brain.', 'URL': None, 'raw_pages': '837-9', 'medline_journal': 'Nature', 'ISO_journal': 'Nature', 'authors': ['Tempel BL', 'Jan YN', 'Jan LY.'], 'DOI_URL': 'http://dx.doi.org/10.1038/332837a0'}, 'PUB00004011': {'PMID': 2448635, 'ISBN': None, 'volume': '331', 'issue': '6152', 'year': 1988, 'title': 'Multiple potassium-channel components are produced by alternative splicing at the Shaker locus in Drosophila.', 'URL': None, 'raw_pages': '137-42', 'medline_journal': 'Nature', 'ISO_journal': 'Nature', 'authors': ['Schwarz TL', 'Tempel BL', 'Papazian DM', 'Jan YN', 'Jan LY.'], 'DOI_URL': 'http://dx.doi.org/10.1038/331137a0'}, 'PUB00008904': {'PMID': 7604285, 'ISBN': None, 'volume': '269', 'issue': '5220', 'year': 1995, 'title': 'HERG, a human inward rectifier in the voltage-gated potassium channel family.', 'URL': None, 'raw_pages': '92-5', 'medline_journal': 'Science', 'ISO_journal': 'Science', 'authors': ['Trudeau MC', 'Warmke JW', 'Ganetzky B', 'Robertson GA.'], 'DOI_URL': 'http://www.sciencemag.org/cgi/content/abstract/269/5220/92'}, 'PUB00001055': {'PMID': 1772658, 'ISBN': None, 'volume': '3', 'issue': '4', 'year': 1991, 'title': 'The molecular biology of K+ channels.', 'URL': None, 'raw_pages': '663-70', 'medline_journal': 'Curr Opin Cell Biol', 'ISO_journal': 'Curr. Opin. Cell Biol.', 'authors': ['Perney TM', 'Kaczmarek LK.'], 'DOI_URL': 'http://dx.doi.org/10.1016/0955-0674(91)90039-2'}, 'PUB00155000': {'PMID': 12684455, 'ISBN': None, 'volume': '23', 'issue': '7', 'year': 2003, 'title': 'Caenorhabditis elegans UNC-103 ERG-like potassium channel regulates contractile behaviors of sex muscles in males before and during mating.', 'URL': None, 'raw_pages': '2696-705', 'medline_journal': 'J Neurosci', 'ISO_journal': 'J Neurosci', 'authors': ['Garcia LR', 'Sternberg PW.'], 'DOI_URL': None}}" "{'prints': {'PR01470': 'ERGCHANNEL'}}" "{'name': 'Potassium channel, voltage-dependent, ERG', 'short': 'K_chnl_volt-dep_ERG'}" "[{'accession': 'IPR014710', 'name': 'RmlC-like jelly roll fold', 'type': 'homologous_superfamily'}, {'accession': 'IPR018490', 'name': 'Cyclic nucleotide-binding domain superfamily', 'type': 'homologous_superfamily'}]" "" "" "interpro" "family" ""