Q8LBL1 · KCO1_ARATH

Function

function

Voltage-independent, large conductance and potassium-selective tonoplast ion channel. Regulated by cytoplasmic calcium and pH. Does not mediate slow-vacuolar (SV) ionic currents, but essential to establish VK currents. Has some permeability for Rb+ and NH4+, but none for Na+, Cs+ or Li+. Involved in intracellular K+ redistribution and/or K+ retranslocation between different tissues.

Miscellaneous

14-3-3 protein binding is not involved in endoplasmic reticulum export and tonoplast targeting.

Caution

Was initially described as an outward slow-vacuolar (SV) ion channel (PubMed:11821043, PubMed:9184204).

Activity regulation

Could be activated by protein kinase C (By similarity).
Strongly induced by calcium. Blocked by barium, tetraethylammonium (TEA), quinine and quinidine

Features

Showing features for site, binding site.

136350100150200250300350
TypeIDPosition(s)Description
Site131Not glycosylated
Binding site301Ca2+ 1 (UniProtKB | ChEBI)
Binding site303Ca2+ 1 (UniProtKB | ChEBI)
Binding site305Ca2+ 1 (UniProtKB | ChEBI)
Binding site312Ca2+ 1 (UniProtKB | ChEBI)
Binding site340Ca2+ 2 (UniProtKB | ChEBI)
Binding site342Ca2+ 2 (UniProtKB | ChEBI)
Binding site344Ca2+ 2 (UniProtKB | ChEBI)
Binding site346Ca2+ 2 (UniProtKB | ChEBI)
Binding site351Ca2+ 2 (UniProtKB | ChEBI)

GO annotations

AspectTerm
Cellular Componentvacuolar membrane
Molecular Functionmetal ion binding
Molecular Functionmonoatomic ion channel activity
Molecular Functionpotassium channel activity
Biological Processcellular response to electrical stimulus
Biological Processintracellular potassium ion homeostasis
Biological Processpotassium ion export across plasma membrane
Biological Processpotassium ion import across plasma membrane
Biological Processregulation of seed germination
Biological Processregulation of stomatal movement

Keywords

Enzyme and pathway databases

Protein family/group databases

Names & Taxonomy

Protein names

  • Recommended name
    Two-pore potassium channel 1
  • Short names
    AtTPK1
  • Alternative names
    • Calcium-activated outward-rectifying potassium channel 1 (AtKCO1)

Gene names

    • Name
      TPK1
    • Synonyms
      KCO1
    • ORF names
      MDF20.7
    • Ordered locus names
      At5g55630

Organism names

  • Taxonomic identifier
  • Strains
    • cv. C24
    • cv. Columbia
  • Taxonomic lineage
    Eukaryota > Viridiplantae > Streptophyta > Embryophyta > Tracheophyta > Spermatophyta > Magnoliopsida > eudicotyledons > Gunneridae > Pentapetalae > rosids > malvids > Brassicales > Brassicaceae > Camelineae > Arabidopsis

Accessions

  • Primary accession
    Q8LBL1
  • Secondary accessions
    • O04718
    • Q0WNY4
    • Q9FM75

Proteomes

Organism-specific databases

Genome annotation databases

Subcellular Location

Vacuole membrane
; Multi-pass membrane protein
Note: Tonoplast.

Features

Showing features for topological domain, transmembrane, intramembrane.

TypeIDPosition(s)Description
Topological domain1-78Cytoplasmic
Transmembrane79-99Helical
Intramembrane111-130Pore-forming; Name=Pore-forming 1
Transmembrane137-157Helical
Topological domain158-197Cytoplasmic
Transmembrane198-218Helical
Intramembrane225-244Pore-forming; Name=Pore-forming 2
Transmembrane251-271Helical
Topological domain272-363Cytoplasmic

Keywords

Phenotypes & Variants

Disruption phenotype

Reduced growth in both high and low K+ conditions. Slower germination and increased sensitivity to abscisic acid. Reduction of the total tonoplast current density.

Features

Showing features for mutagenesis.

TypeIDPosition(s)Description
Mutagenesis42Loss of interaction with GRF6, but no effect on vacuolar targeting.
Mutagenesis296-298Retention in the endoplasmic reticulum.
Mutagenesis301-303No effect on vacuolar targeting.

Variants

We now provide the "Disease & Variants" viewer in its own tab.

The viewer provides 19 variants from UniProt as well as other sources including ClinVar and dbSNP.

Go to variant viewer

PTM/Processing

Features

Showing features for chain.

TypeIDPosition(s)Description
ChainPRO_00001017751-363Two-pore potassium channel 1

Post-translational modification

Phosphorylation at Ser-42 increases and stabilizes the interaction with 14-3-3 proteins.

Keywords

Proteomic databases

PTM databases

Expression

Tissue specificity

Detected in mesophyll cells, guard cells and vascular tissues of the leaves. Expressed in the hilum, where the funiculus is attached during fruit maturation and in the embryo. Also expressed at a lower level in seedlings, root tips and elongation zones, and flowers. Could be detected in mitotically active tissues.

Gene expression databases

Interaction

Subunit

Homodimer. Interacts with GRF1 and GRF6, but only GRF6 modulates the channel activity.

Protein-protein interaction databases

Structure

Family & Domains

Features

Showing features for region, compositional bias, domain, motif.

TypeIDPosition(s)Description
Region1-61Disordered
Compositional bias42-60Basic and acidic residues
Domain288-323EF-hand 1
Motif296-298Endoplasmic reticulum release signal
Domain327-362EF-hand 2

Domain

Each of the two pore-forming region (also called P-domain or P-loop) is enclosed by two transmembrane segments (2P/4TM) and contains the GYGD signature motif which seems to be involved in potassium selectivity. The C-terminus (328-363) is required for vacuolar targeting.

Sequence similarities

Keywords

Phylogenomic databases

Family and domain databases

Sequence

  • Sequence status
    Complete
  • Length
    363
  • Mass (Da)
    40,727
  • Last updated
    2003-11-28 v2
  • Checksum
    149B00AABBE40EFC
MSSDAARTPLLPTEKIDTMAQDFNLNSRTSSSRKRRLRRSRSAPRGDCMYNDDVKIDEPPPHPSKIPMFSDLNPNLRRVIMFLALYLTIGTLCFYLVRDQISGHKTSGVVDALYFCIVTMTTVGYGDLVPNSSASRLLACAFVFSGMVLVGHLLSRAADYLVEKQEALLVRAFHLRQSFGPTDILKELHTNKLRYKCYATCLVLVVLFIVGTIFLVMVEKMPVISAFYCVCSTVTTLGYGDKSFNSEAGRLFAVFWILTSSICLAQFFLYVAELNTENKQRALVKWVLTRRITNNDLEAADLDEDGVVGAAEFIVYKLKEMGKIDEKDISGIMDEFEQLDYDESGTLTTSDIVLAQTTSQIQR

Features

Showing features for compositional bias, sequence conflict.

TypeIDPosition(s)Description
Compositional bias42-60Basic and acidic residues
Sequence conflict227in Ref. 7; AAM64705
Sequence conflict261in Ref. 1; CAA65988 and 3; CAA69158

Keywords

Sequence databases

Nucleotide SequenceProtein SequenceMolecule TypeStatus
X97323
EMBL· GenBank· DDBJ
CAA65988.1
EMBL· GenBank· DDBJ
mRNA
Y07825
EMBL· GenBank· DDBJ
CAA69158.1
EMBL· GenBank· DDBJ
Genomic DNA
AB009050
EMBL· GenBank· DDBJ
BAB09230.1
EMBL· GenBank· DDBJ
Genomic DNA
CP002688
EMBL· GenBank· DDBJ
AED96660.1
EMBL· GenBank· DDBJ
Genomic DNA
CP002688
EMBL· GenBank· DDBJ
AED96661.1
EMBL· GenBank· DDBJ
Genomic DNA
AK229302
EMBL· GenBank· DDBJ
BAF01165.1
EMBL· GenBank· DDBJ
mRNA
AY087147
EMBL· GenBank· DDBJ
AAM64705.1
EMBL· GenBank· DDBJ
mRNA

Genome annotation databases

Similar Proteins

Disclaimer

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