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Protein

Potassium voltage-gated channel subfamily KQT member 2

Gene

Kcnq2

Organism
Rattus norvegicus (Rat)
Status
Reviewed-Annotation score: Annotation score: 5 out of 5-Experimental evidence at protein leveli

Functioni

Associates with KCNQ3 to form a potassium channel with essentially identical properties to the channel underlying the native M-current, a slowly activating and deactivating potassium conductance which plays a critical role in determining the subthreshold electrical excitability of neurons as well as the responsiveness to synaptic inputs. Therefore, it is important in the regulation of neuronal excitability. KCNQ2 current is blocked by barium and tetraethylammonium whereas 4-aminopyridine and charybdotoxin have no effect on KCNQ2 current. Tyrosine kinase inhibitors genistein or herbimycin a markedly down-regulate KCNQ2 current. As the native M-channel, the potassium channel composed of KCNQ2 and KCNQ3 is also suppressed by activation of the muscarinic acetylcholine receptor CHRM1.2 Publications

Miscellaneous

When coexpressed with KCNQ3 subunit in CHO cells or Xenopus oocytes, isoform B was found to have significantly different deactivation-activation kinetics. The kinetics was 2.5 times more slowly than the kinetics of other isoforms. The presence of exon 15a in isoform B accounts for the slow deactivation-activation kinetics. Alternative splicing of the KCNQ2 gene may contribute to the variation in M-current kinetics seen in vivo.

GO - Molecular functioni

  • calmodulin binding Source: UniProtKB
  • protein N-terminus binding Source: RGD
  • voltage-gated potassium channel activity Source: UniProtKB

GO - Biological processi

  • potassium ion transmembrane transport Source: UniProtKB

Keywordsi

Molecular functionIon channel, Potassium channel, Voltage-gated channel
Biological processIon transport, Potassium transport, Transport
LigandPotassium

Names & Taxonomyi

Protein namesi
Recommended name:
Potassium voltage-gated channel subfamily KQT member 2Curated
Alternative name(s):
KQT-like 2
Potassium channel subunit alpha KvLQT2
Voltage-gated potassium channel subunit Kv7.2
Gene namesi
Name:Kcnq2Imported
OrganismiRattus norvegicus (Rat)
Taxonomic identifieri10116 [NCBI]
Taxonomic lineageiEukaryotaMetazoaChordataCraniataVertebrataEuteleostomiMammaliaEutheriaEuarchontogliresGliresRodentiaMyomorphaMuroideaMuridaeMurinaeRattus
Proteomesi
  • UP000002494 Componenti: Unplaced

Organism-specific databases

RGDi621504. Kcnq2.

Subcellular locationi

Extracellular region or secreted Cytosol Plasma membrane Cytoskeleton Lysosome Endosome Peroxisome ER Golgi apparatus Nucleus Mitochondrion Manual annotation Automatic computational assertionGraphics by Christian Stolte; Source: COMPARTMENTS

Topology

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Topological domaini1 – 91CytoplasmicSequence analysisAdd BLAST91
Transmembranei92 – 112Helical; Name=Segment S1Sequence analysisAdd BLAST21
Topological domaini113 – 122ExtracellularSequence analysis10
Transmembranei123 – 143Helical; Name=Segment S2Sequence analysisAdd BLAST21
Topological domaini144 – 166CytoplasmicSequence analysisAdd BLAST23
Transmembranei167 – 187Helical; Name=Segment S3Sequence analysisAdd BLAST21
Topological domaini188 – 197ExtracellularSequence analysis10
Transmembranei198 – 221Helical; Voltage-sensor; Name=Segment S4Sequence analysisAdd BLAST24
Topological domaini222 – 231CytoplasmicSequence analysis10
Transmembranei232 – 252Helical; Name=Segment S5Sequence analysisAdd BLAST21
Topological domaini253 – 264ExtracellularSequence analysisAdd BLAST12
Intramembranei265 – 285Pore-forming; Name=Segment H5Sequence analysisAdd BLAST21
Topological domaini286 – 291ExtracellularSequence analysis6
Transmembranei292 – 312Helical; Name=Segment S6Sequence analysisAdd BLAST21
Topological domaini313 – 852CytoplasmicSequence analysisAdd BLAST540

Keywords - Cellular componenti

Cell membrane, Membrane

Pathology & Biotechi

Chemistry databases

ChEMBLiCHEMBL5530.

PTM / Processingi

Molecule processing

Feature keyPosition(s)DescriptionActionsGraphical viewLength
ChainiPRO_00000540321 – 852Potassium voltage-gated channel subfamily KQT member 2Add BLAST852

Amino acid modifications

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Modified residuei52Phosphoserine; by PKABy similarity1
Modified residuei448PhosphoserineBy similarity1
Modified residuei450PhosphoserineBy similarity1
Modified residuei454PhosphoserineBy similarity1
Modified residuei458PhosphoserineBy similarity1
Modified residuei460PhosphoserineBy similarity1
Modified residuei489PhosphoserineCombined sources1
Modified residuei655PhosphoserineCombined sources1
Modified residuei781PhosphoserineCombined sources1
Modified residuei783PhosphoserineCombined sources1

Post-translational modificationi

KCNQ2/KCNQ3 heteromeric current can be increased by intracellular cyclic AMP, an effect that depends on phosphorylation of Ser-52 in the N-terminal region.By similarity

Keywords - PTMi

Phosphoprotein

Proteomic databases

PaxDbiO88943.
PRIDEiO88943.

PTM databases

iPTMnetiO88943.
PhosphoSitePlusiO88943.
SwissPalmiO88943.

Expressioni

Tissue specificityi

Expressed in brain and sympathetic ganglia. In brain, expressed in cortex, hippocampus, and cerebellum. In sympathetic ganglia, expressed at lower levels in celiac ganglia and superior mesenteric ganglia than in superior cervical ganglia.1 Publication

Interactioni

Subunit structurei

Heterotetramer with KCNQ3; form the heterotetrameric M potassium channel (PubMed:11230508). Interacts with calmodulin; the interaction is calcium-independent, constitutive and participates to the proper assembly of a functional heterotetrameric M channel. May associate with KCNE2 (By similarity).By similarity1 Publication

Binary interactionsi

WithEntry#Exp.IntActNotes
Calm3P621614EBI-7900557,EBI-397530

GO - Molecular functioni

  • calmodulin binding Source: UniProtKB
  • protein N-terminus binding Source: RGD

Protein-protein interaction databases

BioGridi251003. 2 interactors.
IntActiO88943. 1 interactor.
MINTiMINT-8393842.
STRINGi10116.ENSRNOP00000043732.

Chemistry databases

BindingDBiO88943.

Structurei

3D structure databases

ProteinModelPortaliO88943.
ModBaseiSearch...
MobiDBiSearch...

Family & Domainsi

Region

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Regioni317 – 522Mediates interaction with calmodulinBy similarityAdd BLAST206

Motif

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Motifi277 – 282Selectivity filterBy similarity6

Domaini

The segment S4 is probably the voltage-sensor and is characterized by a series of positively charged amino acids at every third position.By similarity

Sequence similaritiesi

Keywords - Domaini

Transmembrane, Transmembrane helix

Phylogenomic databases

eggNOGiKOG1419. Eukaryota.
COG1226. LUCA.
HOGENOMiHOG000220839.
HOVERGENiHBG059014.
InParanoidiO88943.
KOiK04927.

Family and domain databases

InterProiView protein in InterPro
IPR020969. Ankyrin-G_BS.
IPR005821. Ion_trans_dom.
IPR003937. K_chnl_volt-dep_KCNQ.
IPR003947. K_chnl_volt-dep_KCNQ2.
IPR013821. K_chnl_volt-dep_KCNQ_C.
IPR028325. VG_K_chnl.
PANTHERiPTHR11537. PTHR11537. 1 hit.
PfamiView protein in Pfam
PF00520. Ion_trans. 1 hit.
PF03520. KCNQ_channel. 1 hit.
PF11956. KCNQC3-Ank-G_bd. 1 hit.
PRINTSiPR00169. KCHANNEL.
PR01461. KCNQ2CHANNEL.
PR01459. KCNQCHANNEL.

Sequences (9)i

Sequence statusi: Complete.

This entry describes 9 isoformsi produced by alternative splicing. AlignAdd to basket

Note: Splice isoforms fell into three classes, those that contain an in frame exon 16 (Isoforms A-I) those that contain an out-of-frame exon 16 due to an alternative splice junction in exon 14 and those that terminate prematurely to exon 16. Only the forms containing an in frame exon 16 are able to form functional channels. A similar splice pattern is also produced for splice variants that contain an out-of-frame exon 16. A wide variety of different truncated isoforms were isolated for splice variants that terminate prematurely to exon 16.
Isoform A (identifier: O88943-1) [UniParc]FASTAAdd to basket

This isoform has been chosen as the 'canonical' sequence. All positional information in this entry refers to it. This is also the sequence that appears in the downloadable versions of the entry.

« Hide

        10         20         30         40         50
MVQKSRNGGV YPGTSGEKKL KVGFVGLDPG APDSTRDGAL LIAGSEAPKR
60 70 80 90 100
GSVLSKPRTG GAGAGKPPKR NAFYRKLQNF LYNVLERPRG WAFIYHAYVF
110 120 130 140 150
LLVFSCLVLS VFSTIKEYEK SSEGALYILE IVTIVVFGVE YFVRIWAAGC
160 170 180 190 200
CCRYRGWRGR LKFARKPFCV IDIMVLIASI AVLAAGSQGN VFATSALRSL
210 220 230 240 250
RFLQILRMIR MDRRGGTWKL LGSVVYAHSK ELVTAWYIGF LCLILASFLV
260 270 280 290 300
YLAEKGENDH FDTYADALWW GLITLTTIGY GDKYPQTWNG RLLAATFTLI
310 320 330 340 350
GVSFFALPAG ILGSGFALKV QEQHRQKHFE KRRNPAAGLI QSAWRFYATN
360 370 380 390 400
LSRTDLHSTW QYYERTVTVP MISSQTQTYG ASRLIPPLNQ LEMLRNLKSK
410 420 430 440 450
SGLTFRKEPQ PEPSPSQKVS LKDRVFSSPR GVAAKGKGSP QAQTVRRSPS
460 470 480 490 500
ADQSLDDSPS KVPKSWSFGD RSRARQAFRI KGAASRQNSE EASLPGEDIV
510 520 530 540 550
EDNKSCNCEF VTEDLTPGLK VSIRAVCVMR FLVSKRKFKE SLRPYDVMDV
560 570 580 590 600
IEQYSAGHLD MLSRIKSLQS RVDQIVGRGP TITDKDRTKG PAETELPEDP
610 620 630 640 650
SMMGRLGKVE KQVLSMEKKL DFLVSIYTQR MGIPPAETEA YFGAKEPEPA
660 670 680 690 700
PPYHSPEDSR DHADKHGCII KIVRSTSSTG QRKYAAPPVM PPAECPPSTS
710 720 730 740 750
WQQSHQRHGT SPVGDHGSLV RIPPPPAHER SLSAYSGGNR ASTEFLRLEG
760 770 780 790 800
TPACRPSEAA LRDSDTSISI PSVDHEELER SFSGFSISQS KENLNALASC
810 820 830 840 850
YAAVAPCAKV RPYIAEGESD TDSDLCTPCG PPPRSATGEG PFGDVAWAGP

RK
Length:852
Mass (Da):93,949
Last modified:November 1, 1998 - v1
Checksum:i82A5FE462A5F259A
GO
Isoform B (identifier: O88943-2) [UniParc]FASTAAdd to basket

The sequence of this isoform differs from the canonical sequence as follows:
     417-428: Missing.
     571-571: R → RIDMIVGPPPPSTPRHKKYPTKGPTAPSRESPQYSPR

Show »
Length:876
Mass (Da):96,527
Checksum:i06AE81A7E5C27C4D
GO
Isoform C (identifier: O88943-3) [UniParc]FASTAAdd to basket

The sequence of this isoform differs from the canonical sequence as follows:
     373-382: Missing.

Show »
Length:842
Mass (Da):92,938
Checksum:i308CAC7617E71566
GO
Isoform D (identifier: O88943-4) [UniParc]FASTAAdd to basket

The sequence of this isoform differs from the canonical sequence as follows:
     416-416: S → SKGRPCRGCLCGCRPGHSS
     491-491: Missing.

Show »
Length:869
Mass (Da):95,676
Checksum:iADBA2B0BFC7352E5
GO
Isoform E (identifier: O88943-5) [UniParc]FASTAAdd to basket

The sequence of this isoform differs from the canonical sequence as follows:
     416-416: S → SKGRPCRGCLCGCRPGHSS

Show »
Length:870
Mass (Da):95,806
Checksum:iEFE03926DD670D01
GO
Isoform F (identifier: O88943-6) [UniParc]FASTAAdd to basket

The sequence of this isoform differs from the canonical sequence as follows:
     373-382: Missing.
     416-416: S → SKGRPCRGCLCGCRPGHSS
     491-491: Missing.

Show »
Length:859
Mass (Da):94,665
Checksum:i802DB2815AB14F81
GO
Isoform G (identifier: O88943-7) [UniParc]FASTAAdd to basket

The sequence of this isoform differs from the canonical sequence as follows:
     571-571: R → RIDMIVGPPPPSTPRHKKYPTKGPTAPSRESPQYSPR

Show »
Length:888
Mass (Da):97,903
Checksum:i7B08419F3BED3C66
GO
Isoform H (identifier: O88943-8) [UniParc]FASTAAdd to basket

The sequence of this isoform differs from the canonical sequence as follows:
     373-382: Missing.
     416-416: S → SKGRPCRGCLCGCRPGHSS

Show »
Length:860
Mass (Da):94,795
Checksum:iB30DAEBF57C1CF1C
GO
Isoform I (identifier: O88943-9) [UniParc]FASTAAdd to basket

The sequence of this isoform differs from the canonical sequence as follows:
     491-491: Missing.

Show »
Length:851
Mass (Da):93,820
Checksum:i587D4BFCC45BC9A4
GO

Alternative sequence

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Alternative sequenceiVSP_001007373 – 382Missing in isoform C, isoform F and isoform H. Curated10
Alternative sequenceiVSP_001008416S → SKGRPCRGCLCGCRPGHSS in isoform D, isoform E, isoform F and isoform H. Curated1
Alternative sequenceiVSP_001009417 – 428Missing in isoform B. CuratedAdd BLAST12
Alternative sequenceiVSP_001010491Missing in isoform D, isoform F and isoform I. Curated1
Alternative sequenceiVSP_001011571R → RIDMIVGPPPPSTPRHKKYP TKGPTAPSRESPQYSPR in isoform B and isoform G. Curated1

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
AF087453 mRNA. Translation: AAC36722.1.
RefSeqiNP_579856.1. NM_133322.1. [O88943-1]
UniGeneiRn.33317.

Genome annotation databases

GeneIDi170848.
KEGGirno:170848.
UCSCiRGD:621504. rat. [O88943-1]

Keywords - Coding sequence diversityi

Alternative splicing

Similar proteinsi

Entry informationi

Entry nameiKCNQ2_RAT
AccessioniPrimary (citable) accession number: O88943
Entry historyiIntegrated into UniProtKB/Swiss-Prot: June 1, 2001
Last sequence update: November 1, 1998
Last modified: September 27, 2017
This is version 138 of the entry and version 1 of the sequence. See complete history.
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programChordata Protein Annotation Program

Miscellaneousi

Keywords - Technical termi

Complete proteome, Reference proteome

Documents

  1. SIMILARITY comments
    Index of protein domains and families