AbbreviationsKy,voltage-gatedK+ channel;BKca,largeconductanceCa2+-activatedK+channel;SKca,smallconductanceCa2+-activatedK+channel;EAG,ether-a-go-goK+channel;hERG, human ether-a-go-go-related K+ channel;IKca,intermediate conductance Ca2+-activated K+channel;IKr, cardiac rapid delayed rectifier; IKs, cardiac slow delayed rectifier;IKur, ultrarapid delayed rectifier; IKro,transient outward delayedrectifier;KATp,ATP-sensitiveKt;KCsA,K+channelfromStreptomyceslividans;Kir,inward rectifierK+ channel; Kco,K+ channel opener;M-channel,muscarine-sensitiveK+channel;TWiK,two-pore weak inward rectifier;TREK,two-poreweakinwardrectifier-related K+ channel;TEA,tetraethylammonium;4-AP,4-aminopyridine;MiRP,minKrelated peptide;PHHl,persistenthyperinsulinemichypoglycemiaofinfancy;PS,presenilin;suR,sulfonylureareceptor
Abbreviations Kv , voltage-gated K+ channel; BKCa , large conductance Ca2+-activated K+ channel; SKCa , small conductance Ca2+-activated K+ channel; EAG, ether-a-go-go K+ channel; hERG, human ether-a-go-go-related K+ channel; IKCa , intermediate conductance Ca2+-activated K+ channel; IKr , cardiac rapid delayed rectifier; IKs, cardiac slow delayed rectifier; IKur , ultrarapid delayed rectifier; IKTO , transient outward delayed rectifier; KATP , ATP-sensitive K +; KCsA, K+ channel from Streptomyces lividans; Kir , inward rectifier K+ channel; KCO , K+ channel opener; M-channel, muscarine-sensitive K+ channel; TWIK, two-pore weak inward rectifier; TREK, two-pore weak inward rectifier-related K+ channel; TEA, tetraethylammonium; 4-AP, 4-aminopyridine; MiRP, minK related peptide; PHHI, persistent hyperinsulinemic hypoglycemia of infancy; PS, presenilin; SUR, sulfonylurea receptor
NomenclatureAstandardisednomenclatureforthesix-transmembranedomain(TM),voltage-gatedK+channelgenes-theKnamingsystem-was widely adopted.This nomenclaturewas based ondeduced phylogenetic relationships;channelsthat shared 65%sequence identitybeingassignedtoonesubfamilyAparallelnomenclature-KcN-wasdevelopedbytheHumanGenome Organisation(HUGO).Sincethen,theK+channelsuperfamily of genes has greatly expandedrequiring an updateofthe namingsystem
Nomenclature A standardised nomenclature for the six-transmembrane domain (TM), voltage-gated K+ channel genes – the KV naming system – was widely adopted. This nomenclature was based on deduced phylogenetic relationships; channels that shared 65% sequence identity being assigned to one subfamily. A parallel nomenclature – KCN – was developed by the Human Genome Organisation (HUGO). Since then, the K+ channel superfamily of genes has greatly expanded, requiring an update of the naming system
FeaturesofKtchannelK+channelsselectively conductK+ionsacrossthe cellmembrane along its electrochemical gradient at a rate of 1o6 to108ions/s.Asetofsalientfeatures:a water-filledpermeationpathway(pore)that allowsK+ionsto flowacrossthe cell membrane;a selectivityfilterthat specifiesKtas permeant ionspecies;a gatingmechanismthat servesto switchbetween open and福closed channelconformations.Sincethe first gene encodinga K+ channel was cloned fromDrosophila Shaker mutant, more than 2oo genesencodingavariety of Kt channels have been identified,all containing ahomologousporesegment(S5-S6linker)selectiveforK+ions
Features of K+ channel K+ channels selectively conduct K+ ions across the cell membrane along its electrochemical gradient at a rate of 106 to 108 ions/s. A set of salient features: a water-filled permeation pathway (pore) that allows K+ ions to flow across the cell membrane; a selectivity filter that specifies K+ as permeant ion species; a gating mechanism that serves to switch between open and closed channel conformations. Since the first gene encoding a K+ channel was cloned from Drosophila Shaker mutant, more than 200 genes encoding a variety of K+ channels have been identified, all containing a homologous pore segment (S5-S6 linker) selective for K+ ions
Growth of genes encoding diverse K+ channelsOthersAV250Human200e15010050093‘95'9799
Growth of genes encoding diverse K+ channels
Channel diversity and classification
Channel diversity and classification