KCO1_ARATH
ID KCO1_ARATH Reviewed; 363 AA.
AC Q8LBL1; O04718; Q0WNY4; Q9FM75;
DT 28-NOV-2003, integrated into UniProtKB/Swiss-Prot.
DT 28-NOV-2003, sequence version 2.
DT 03-AUG-2022, entry version 156.
DE RecName: Full=Two-pore potassium channel 1;
DE Short=AtTPK1;
DE AltName: Full=Calcium-activated outward-rectifying potassium channel 1;
DE Short=AtKCO1;
GN Name=TPK1; Synonyms=KCO1; OrderedLocusNames=At5g55630; ORFNames=MDF20.7;
OS Arabidopsis thaliana (Mouse-ear cress).
OC Eukaryota; Viridiplantae; Streptophyta; Embryophyta; Tracheophyta;
OC Spermatophyta; Magnoliopsida; eudicotyledons; Gunneridae; Pentapetalae;
OC rosids; malvids; Brassicales; Brassicaceae; Camelineae; Arabidopsis.
OX NCBI_TaxID=3702;
RN [1]
RP NUCLEOTIDE SEQUENCE [GENOMIC DNA / MRNA], AND CHARACTERIZATION.
RC STRAIN=cv. C24;
RX PubMed=9184204; DOI=10.1093/emboj/16.10.2565;
RA Czempinski K., Zimmermann S., Ehrhardt T., Mueller-Roeber B.;
RT "New structure and function in plant K+ channels: KCO1, an outward
RT rectifier with a steep Ca2+ dependency.";
RL EMBO J. 16:2565-2575(1997).
RN [2]
RP ERRATUM OF PUBMED:9184204.
RA Czempinski K., Zimmermann S., Ehrhardt T., Mueller-Roeber B.;
RL EMBO J. 16:6896-6896(1997).
RN [3]
RP NUCLEOTIDE SEQUENCE [GENOMIC DNA], SUBCELLULAR LOCATION, AND TISSUE
RP SPECIFICITY.
RC STRAIN=cv. C24;
RX PubMed=12148538; DOI=10.1046/j.1365-313x.2002.01260.x;
RA Czempinski K., Frachisse J.-M., Maurel C., Barbier-Brygoo H.,
RA Mueller-Roeber B.;
RT "Vacuolar membrane localization of the Arabidopsis 'two-pore' K+ channel
RT KCO1.";
RL Plant J. 29:809-820(2002).
RN [4]
RP NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC STRAIN=cv. Columbia;
RX PubMed=9628582; DOI=10.1093/dnares/5.1.41;
RA Sato S., Kaneko T., Kotani H., Nakamura Y., Asamizu E., Miyajima N.,
RA Tabata S.;
RT "Structural analysis of Arabidopsis thaliana chromosome 5. IV. Sequence
RT features of the regions of 1,456,315 bp covered by nineteen physically
RT assigned P1 and TAC clones.";
RL DNA Res. 5:41-54(1998).
RN [5]
RP GENOME REANNOTATION.
RC STRAIN=cv. Columbia;
RX PubMed=27862469; DOI=10.1111/tpj.13415;
RA Cheng C.Y., Krishnakumar V., Chan A.P., Thibaud-Nissen F., Schobel S.,
RA Town C.D.;
RT "Araport11: a complete reannotation of the Arabidopsis thaliana reference
RT genome.";
RL Plant J. 89:789-804(2017).
RN [6]
RP NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA].
RC STRAIN=cv. Columbia;
RA Totoki Y., Seki M., Ishida J., Nakajima M., Enju A., Kamiya A.,
RA Narusaka M., Shin-i T., Nakagawa M., Sakamoto N., Oishi K., Kohara Y.,
RA Kobayashi M., Toyoda A., Sakaki Y., Sakurai T., Iida K., Akiyama K.,
RA Satou M., Toyoda T., Konagaya A., Carninci P., Kawai J., Hayashizaki Y.,
RA Shinozaki K.;
RT "Large-scale analysis of RIKEN Arabidopsis full-length (RAFL) cDNAs.";
RL Submitted (JUL-2006) to the EMBL/GenBank/DDBJ databases.
RN [7]
RP NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA].
RA Brover V.V., Troukhan M.E., Alexandrov N.A., Lu Y.-P., Flavell R.B.,
RA Feldmann K.A.;
RT "Full-length cDNA from Arabidopsis thaliana.";
RL Submitted (MAR-2002) to the EMBL/GenBank/DDBJ databases.
RN [8]
RP GENE FAMILY, AND NOMENCLATURE.
RX PubMed=11500563; DOI=10.1104/pp.126.4.1646;
RA Maeser P., Thomine S., Schroeder J.I., Ward J.M., Hirschi K., Sze H.,
RA Talke I.N., Amtmann A., Maathuis F.J.M., Sanders D., Harper J.F.,
RA Tchieu J., Gribskov M., Persans M.W., Salt D.E., Kim S.A., Guerinot M.L.;
RT "Phylogenetic relationships within cation transporter families of
RT Arabidopsis.";
RL Plant Physiol. 126:1646-1667(2001).
RN [9]
RP CHARACTERIZATION, AND NULL MUTANT KCO1-7.
RX PubMed=11821043; DOI=10.1016/s0014-5793(01)03273-2;
RA Schoenknecht G., Spoormaker P., Steinmeyer R., Brueggeman L., Ache P.,
RA Dutta R., Reintanz B., Godde M., Hedrich R., Palme K.;
RT "KCO1 is a component of the slow-vacuolar (SV) ion channel.";
RL FEBS Lett. 511:28-32(2002).
RN [10]
RP GENE FAMILY, AND NOMENCLATURE.
RX PubMed=15505206; DOI=10.1073/pnas.0401502101;
RA Becker D., Geiger D., Dunkel M., Roller A., Bertl A., Latz A.,
RA Carpaneto A., Dietrich P., Roelfsema M.R., Voelker C., Schmidt D.,
RA Mueller-Roeber B., Czempinski K., Hedrich R.;
RT "AtTPK4, an Arabidopsis tandem-pore K+ channel, poised to control the
RT pollen membrane voltage in a pH- and Ca2+-dependent manner.";
RL Proc. Natl. Acad. Sci. U.S.A. 101:15621-15626(2004).
RN [11]
RP FUNCTION, AND ACTIVITY REGULATION.
RX PubMed=16113216; DOI=10.1104/pp.105.065599;
RA Bihler H., Eing C., Hebeisen S., Roller A., Czempinski K., Bertl A.;
RT "TPK1 is a vacuolar ion channel different from the slow-vacuolar cation
RT channel.";
RL Plant Physiol. 139:417-424(2005).
RN [12]
RP TISSUE SPECIFICITY, AND SUBUNIT.
RX PubMed=16984403; DOI=10.1111/j.1365-313x.2006.02868.x;
RA Voelker C., Schmidt D., Mueller-Roeber B., Czempinski K.;
RT "Members of the Arabidopsis AtTPK/KCO family form homomeric vacuolar
RT channels in planta.";
RL Plant J. 48:296-306(2006).
RN [13]
RP FUNCTION, INTERACTION WITH GRF1 AND GRF6, MUTAGENESIS OF SER-42,
RP PHOSPHORYLATION, AND 3D-STRUCTURE MODELING.
RX PubMed=17764516; DOI=10.1111/j.1365-313x.2007.03255.x;
RA Latz A., Becker D., Hekman M., Mueller T., Beyhl D., Marten I., Eing C.,
RA Fischer A., Dunkel M., Bertl A., Rapp U.R., Hedrich R.;
RT "TPK1, a Ca(2+)-regulated Arabidopsis vacuole two-pore K(+) channel is
RT activated by 14-3-3 proteins.";
RL Plant J. 52:449-459(2007).
RN [14]
RP FUNCTION, DISRUPTION PHENOTYPE, AND ACTIVITY REGULATION.
RC STRAIN=cv. Columbia;
RX PubMed=17563365; DOI=10.1073/pnas.0702595104;
RA Gobert A., Isayenkov S., Voelker C., Czempinski K., Maathuis F.J.;
RT "The two-pore channel TPK1 gene encodes the vacuolar K+ conductance and
RT plays a role in K+ homeostasis.";
RL Proc. Natl. Acad. Sci. U.S.A. 104:10726-10731(2007).
RN [15]
RP SUBCELLULAR LOCATION, AND MUTAGENESIS OF 296-ASP--GLU-298 AND
RP 301-ASP--ASP-303.
RX PubMed=19825594; DOI=10.1093/mp/ssn064;
RA Dunkel M., Latz A., Schumacher K., Mueller T., Becker D., Hedrich R.;
RT "Targeting of vacuolar membrane localized members of the TPK channel
RT family.";
RL Mol. Plant 1:938-949(2008).
RN [16]
RP FUNCTION, SUBUNIT, SUBCELLULAR LOCATION, AND GLYCOSYLATION.
RC STRAIN=cv. Columbia;
RX PubMed=21697507; DOI=10.1104/pp.111.177816;
RA Maitrejean M., Wudick M.M., Voelker C., Prinsi B., Mueller-Roeber B.,
RA Czempinski K., Pedrazzini E., Vitale A.;
RT "Assembly and sorting of the tonoplast potassium channel AtTPK1 and its
RT turnover by internalization into the vacuole.";
RL Plant Physiol. 156:1783-1796(2011).
CC -!- FUNCTION: Voltage-independent, large conductance and potassium-
CC selective tonoplast ion channel. Regulated by cytoplasmic calcium and
CC pH. Does not mediate slow-vacuolar (SV) ionic currents, but essential
CC to establish VK currents. Has some permeability for Rb(+) and NH(4)(+),
CC but none for Na(+), Cs(+) or Li(+). Involved in intracellular K(+)
CC redistribution and/or K(+) retranslocation between different tissues.
CC {ECO:0000269|PubMed:16113216, ECO:0000269|PubMed:17563365,
CC ECO:0000269|PubMed:17764516, ECO:0000269|PubMed:21697507}.
CC -!- ACTIVITY REGULATION: Could be activated by protein kinase C (By
CC similarity). Strongly induced by calcium. Blocked by barium,
CC tetraethylammonium (TEA), quinine and quinidine. {ECO:0000250,
CC ECO:0000269|PubMed:16113216, ECO:0000269|PubMed:17563365}.
CC -!- SUBUNIT: Homodimer. Interacts with GRF1 and GRF6, but only GRF6
CC modulates the channel activity. {ECO:0000269|PubMed:16984403,
CC ECO:0000269|PubMed:17764516, ECO:0000269|PubMed:21697507}.
CC -!- SUBCELLULAR LOCATION: Vacuole membrane {ECO:0000269|PubMed:12148538,
CC ECO:0000269|PubMed:19825594, ECO:0000269|PubMed:21697507}; Multi-pass
CC membrane protein {ECO:0000269|PubMed:12148538,
CC ECO:0000269|PubMed:19825594, ECO:0000269|PubMed:21697507}.
CC Note=Tonoplast.
CC -!- TISSUE SPECIFICITY: Detected in mesophyll cells, guard cells and
CC vascular tissues of the leaves. Expressed in the hilum, where the
CC funiculus is attached during fruit maturation and in the embryo. Also
CC expressed at a lower level in seedlings, root tips and elongation
CC zones, and flowers. Could be detected in mitotically active tissues.
CC {ECO:0000269|PubMed:12148538, ECO:0000269|PubMed:16984403}.
CC -!- DOMAIN: Each of the two pore-forming region (also called P-domain or P-
CC loop) is enclosed by two transmembrane segments (2P/4TM) and contains
CC the GYGD signature motif which seems to be involved in potassium
CC selectivity. The C-terminus (328-363) is required for vacuolar
CC targeting.
CC -!- PTM: Phosphorylation at Ser-42 increases and stabilizes the interaction
CC with 14-3-3 proteins. {ECO:0000269|PubMed:17764516}.
CC -!- DISRUPTION PHENOTYPE: Reduced growth in both high and low K(+)
CC conditions. Slower germination and increased sensitivity to abscisic
CC acid. Reduction of the total tonoplast current density.
CC {ECO:0000269|PubMed:17563365}.
CC -!- MISCELLANEOUS: 14-3-3 protein binding is not involved in endoplasmic
CC reticulum export and tonoplast targeting.
CC -!- SIMILARITY: Belongs to the two pore domain potassium channel (TC
CC 1.A.1.7) family. {ECO:0000305}.
CC -!- CAUTION: Was initially described as an outward slow-vacuolar (SV) ion
CC channel (PubMed:9184204 and PubMed:11821043). {ECO:0000305}.
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DR EMBL; X97323; CAA65988.1; -; mRNA.
DR EMBL; Y07825; CAA69158.1; -; Genomic_DNA.
DR EMBL; AB009050; BAB09230.1; -; Genomic_DNA.
DR EMBL; CP002688; AED96660.1; -; Genomic_DNA.
DR EMBL; CP002688; AED96661.1; -; Genomic_DNA.
DR EMBL; AK229302; BAF01165.1; -; mRNA.
DR EMBL; AY087147; AAM64705.1; -; mRNA.
DR RefSeq; NP_200374.1; NM_124945.4.
DR RefSeq; NP_851196.1; NM_180865.1.
DR AlphaFoldDB; Q8LBL1; -.
DR SMR; Q8LBL1; -.
DR BioGRID; 20901; 27.
DR IntAct; Q8LBL1; 22.
DR STRING; 3702.AT5G55630.1; -.
DR TCDB; 1.A.1.7.3; the voltage-gated ion channel (vic) superfamily.
DR iPTMnet; Q8LBL1; -.
DR PaxDb; Q8LBL1; -.
DR PRIDE; Q8LBL1; -.
DR ProteomicsDB; 250632; -.
DR EnsemblPlants; AT5G55630.1; AT5G55630.1; AT5G55630.
DR EnsemblPlants; AT5G55630.2; AT5G55630.2; AT5G55630.
DR GeneID; 835657; -.
DR Gramene; AT5G55630.1; AT5G55630.1; AT5G55630.
DR Gramene; AT5G55630.2; AT5G55630.2; AT5G55630.
DR KEGG; ath:AT5G55630; -.
DR Araport; AT5G55630; -.
DR TAIR; locus:2162162; AT5G55630.
DR eggNOG; KOG1418; Eukaryota.
DR HOGENOM; CLU_033675_0_1_1; -.
DR InParanoid; Q8LBL1; -.
DR OMA; HPSKIPM; -.
DR OrthoDB; 774951at2759; -.
DR PhylomeDB; Q8LBL1; -.
DR BioCyc; ARA:AT5G55630-MON; -.
DR BioCyc; MetaCyc:MON-14554; -.
DR PRO; PR:Q8LBL1; -.
DR Proteomes; UP000006548; Chromosome 5.
DR ExpressionAtlas; Q8LBL1; baseline and differential.
DR Genevisible; Q8LBL1; AT.
DR GO; GO:0005887; C:integral component of plasma membrane; IBA:GO_Central.
DR GO; GO:0009705; C:plant-type vacuole membrane; IBA:GO_Central.
DR GO; GO:0005774; C:vacuolar membrane; IDA:TAIR.
DR GO; GO:0005216; F:ion channel activity; IDA:TAIR.
DR GO; GO:0046872; F:metal ion binding; IEA:UniProtKB-KW.
DR GO; GO:0015271; F:outward rectifier potassium channel activity; IBA:GO_Central.
DR GO; GO:0022841; F:potassium ion leak channel activity; IBA:GO_Central.
DR GO; GO:0030007; P:cellular potassium ion homeostasis; IMP:TAIR.
DR GO; GO:0071257; P:cellular response to electrical stimulus; IDA:TAIR.
DR GO; GO:0097623; P:potassium ion export across plasma membrane; IDA:TAIR.
DR GO; GO:1990573; P:potassium ion import across plasma membrane; IDA:TAIR.
DR GO; GO:0071805; P:potassium ion transmembrane transport; IBA:GO_Central.
DR GO; GO:0010029; P:regulation of seed germination; IMP:TAIR.
DR GO; GO:0010119; P:regulation of stomatal movement; IMP:TAIR.
DR GO; GO:0030322; P:stabilization of membrane potential; IBA:GO_Central.
DR InterPro; IPR003280; 2pore_dom_K_chnl.
DR InterPro; IPR011992; EF-hand-dom_pair.
DR InterPro; IPR018247; EF_Hand_1_Ca_BS.
DR InterPro; IPR013099; K_chnl_dom.
DR PANTHER; PTHR11003; PTHR11003; 1.
DR Pfam; PF07885; Ion_trans_2; 2.
DR PRINTS; PR01333; 2POREKCHANEL.
DR SUPFAM; SSF47473; SSF47473; 1.
DR PROSITE; PS00018; EF_HAND_1; 2.
PE 1: Evidence at protein level;
KW Calcium; Ion channel; Ion transport; Membrane; Metal-binding;
KW Phosphoprotein; Potassium; Potassium channel; Potassium transport;
KW Reference proteome; Repeat; Transmembrane; Transmembrane helix; Transport;
KW Vacuole.
FT CHAIN 1..363
FT /note="Two-pore potassium channel 1"
FT /id="PRO_0000101775"
FT TOPO_DOM 1..78
FT /note="Cytoplasmic"
FT /evidence="ECO:0000255"
FT TRANSMEM 79..99
FT /note="Helical"
FT /evidence="ECO:0000255"
FT INTRAMEM 111..130
FT /note="Pore-forming; Name=Pore-forming 1"
FT /evidence="ECO:0000255"
FT TRANSMEM 137..157
FT /note="Helical"
FT /evidence="ECO:0000255"
FT TOPO_DOM 158..197
FT /note="Cytoplasmic"
FT /evidence="ECO:0000255"
FT TRANSMEM 198..218
FT /note="Helical"
FT /evidence="ECO:0000255"
FT INTRAMEM 225..244
FT /note="Pore-forming; Name=Pore-forming 2"
FT /evidence="ECO:0000255"
FT TRANSMEM 251..271
FT /note="Helical"
FT /evidence="ECO:0000255"
FT TOPO_DOM 272..363
FT /note="Cytoplasmic"
FT /evidence="ECO:0000255"
FT DOMAIN 288..323
FT /note="EF-hand 1"
FT DOMAIN 327..362
FT /note="EF-hand 2"
FT REGION 1..61
FT /note="Disordered"
FT /evidence="ECO:0000256|SAM:MobiDB-lite"
FT MOTIF 296..298
FT /note="Endoplasmic reticulum release signal"
FT COMPBIAS 42..60
FT /note="Basic and acidic residues"
FT /evidence="ECO:0000256|SAM:MobiDB-lite"
FT BINDING 301
FT /ligand="Ca(2+)"
FT /ligand_id="ChEBI:CHEBI:29108"
FT /ligand_label="1"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU10142"
FT BINDING 303
FT /ligand="Ca(2+)"
FT /ligand_id="ChEBI:CHEBI:29108"
FT /ligand_label="1"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU10142"
FT BINDING 305
FT /ligand="Ca(2+)"
FT /ligand_id="ChEBI:CHEBI:29108"
FT /ligand_label="1"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU10142"
FT BINDING 312
FT /ligand="Ca(2+)"
FT /ligand_id="ChEBI:CHEBI:29108"
FT /ligand_label="1"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU10142"
FT BINDING 340
FT /ligand="Ca(2+)"
FT /ligand_id="ChEBI:CHEBI:29108"
FT /ligand_label="2"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU10142"
FT BINDING 342
FT /ligand="Ca(2+)"
FT /ligand_id="ChEBI:CHEBI:29108"
FT /ligand_label="2"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU10142"
FT BINDING 344
FT /ligand="Ca(2+)"
FT /ligand_id="ChEBI:CHEBI:29108"
FT /ligand_label="2"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU10142"
FT BINDING 346
FT /ligand="Ca(2+)"
FT /ligand_id="ChEBI:CHEBI:29108"
FT /ligand_label="2"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU10142"
FT BINDING 351
FT /ligand="Ca(2+)"
FT /ligand_id="ChEBI:CHEBI:29108"
FT /ligand_label="2"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU10142"
FT SITE 131
FT /note="Not glycosylated"
FT MUTAGEN 42
FT /note="S->A: Loss of interaction with GRF6, but no effect
FT on vacuolar targeting."
FT /evidence="ECO:0000269|PubMed:17764516"
FT MUTAGEN 296..298
FT /note="DLE->GLG: Retention in the endoplasmic reticulum."
FT /evidence="ECO:0000269|PubMed:19825594"
FT MUTAGEN 301..303
FT /note="DLD->GLG: No effect on vacuolar targeting."
FT /evidence="ECO:0000269|PubMed:19825594"
FT CONFLICT 227
FT /note="F -> V (in Ref. 7; AAM64705)"
FT /evidence="ECO:0000305"
FT CONFLICT 261
FT /note="S -> T (in Ref. 1; CAA65988 and 3; CAA69158)"
FT /evidence="ECO:0000305"
SQ SEQUENCE 363 AA; 40727 MW; 149B00AABBE40EFC CRC64;
MSSDAARTPL LPTEKIDTMA QDFNLNSRTS SSRKRRLRRS RSAPRGDCMY NDDVKIDEPP
PHPSKIPMFS DLNPNLRRVI MFLALYLTIG TLCFYLVRDQ ISGHKTSGVV DALYFCIVTM
TTVGYGDLVP NSSASRLLAC AFVFSGMVLV GHLLSRAADY LVEKQEALLV RAFHLRQSFG
PTDILKELHT NKLRYKCYAT CLVLVVLFIV GTIFLVMVEK MPVISAFYCV CSTVTTLGYG
DKSFNSEAGR LFAVFWILTS SICLAQFFLY VAELNTENKQ RALVKWVLTR RITNNDLEAA
DLDEDGVVGA AEFIVYKLKE MGKIDEKDIS GIMDEFEQLD YDESGTLTTS DIVLAQTTSQ
IQR
