Q8LBL1 · KCO1_ARATH
- ProteinTwo-pore potassium channel 1
- GeneTPK1
- StatusUniProtKB reviewed (Swiss-Prot)
- Amino acids363 (go to sequence)
- Protein existenceEvidence at protein level
- Annotation score5/5
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.
Activity regulation
Could be activated by protein kinase C (By similarity).
Strongly induced by calcium. Blocked by barium, tetraethylammonium (TEA), quinine and quinidine
Strongly induced by calcium. Blocked by barium, tetraethylammonium (TEA), quinine and quinidine
Features
Showing features for site, binding site.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Site | 131 | Not glycosylated | ||||
Sequence: N | ||||||
Binding site | 301 | Ca2+ 1 (UniProtKB | ChEBI) | ||||
Sequence: D | ||||||
Binding site | 303 | Ca2+ 1 (UniProtKB | ChEBI) | ||||
Sequence: D | ||||||
Binding site | 305 | Ca2+ 1 (UniProtKB | ChEBI) | ||||
Sequence: D | ||||||
Binding site | 312 | Ca2+ 1 (UniProtKB | ChEBI) | ||||
Sequence: E | ||||||
Binding site | 340 | Ca2+ 2 (UniProtKB | ChEBI) | ||||
Sequence: D | ||||||
Binding site | 342 | Ca2+ 2 (UniProtKB | ChEBI) | ||||
Sequence: D | ||||||
Binding site | 344 | Ca2+ 2 (UniProtKB | ChEBI) | ||||
Sequence: S | ||||||
Binding site | 346 | Ca2+ 2 (UniProtKB | ChEBI) | ||||
Sequence: T | ||||||
Binding site | 351 | Ca2+ 2 (UniProtKB | ChEBI) | ||||
Sequence: D |
GO annotations
Aspect | Term | |
---|---|---|
Cellular Component | vacuolar membrane | |
Molecular Function | metal ion binding | |
Molecular Function | monoatomic ion channel activity | |
Molecular Function | potassium channel activity | |
Biological Process | cellular response to electrical stimulus | |
Biological Process | intracellular potassium ion homeostasis | |
Biological Process | potassium ion export across plasma membrane | |
Biological Process | potassium ion import across plasma membrane | |
Biological Process | regulation of seed germination | |
Biological Process | regulation of stomatal movement |
Keywords
- Molecular function
- Biological process
- Ligand
Enzyme and pathway databases
Protein family/group databases
Names & Taxonomy
Protein names
- Recommended nameTwo-pore potassium channel 1
- Short namesAtTPK1
- Alternative names
Gene names
Organism names
- Strains
- Taxonomic lineageEukaryota > Viridiplantae > Streptophyta > Embryophyta > Tracheophyta > Spermatophyta > Magnoliopsida > eudicotyledons > Gunneridae > Pentapetalae > rosids > malvids > Brassicales > Brassicaceae > Camelineae > Arabidopsis
Accessions
- Primary accessionQ8LBL1
- Secondary accessions
Proteomes
Organism-specific databases
Genome annotation databases
Subcellular Location
UniProt Annotation
GO Annotation
Vacuole membrane ; Multi-pass membrane protein
Note: Tonoplast.
Features
Showing features for topological domain, transmembrane, intramembrane.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Topological domain | 1-78 | Cytoplasmic | ||||
Sequence: MSSDAARTPLLPTEKIDTMAQDFNLNSRTSSSRKRRLRRSRSAPRGDCMYNDDVKIDEPPPHPSKIPMFSDLNPNLRR | ||||||
Transmembrane | 79-99 | Helical | ||||
Sequence: VIMFLALYLTIGTLCFYLVRD | ||||||
Intramembrane | 111-130 | Pore-forming; Name=Pore-forming 1 | ||||
Sequence: DALYFCIVTMTTVGYGDLVP | ||||||
Transmembrane | 137-157 | Helical | ||||
Sequence: LLACAFVFSGMVLVGHLLSRA | ||||||
Topological domain | 158-197 | Cytoplasmic | ||||
Sequence: ADYLVEKQEALLVRAFHLRQSFGPTDILKELHTNKLRYKC | ||||||
Transmembrane | 198-218 | Helical | ||||
Sequence: YATCLVLVVLFIVGTIFLVMV | ||||||
Intramembrane | 225-244 | Pore-forming; Name=Pore-forming 2 | ||||
Sequence: SAFYCVCSTVTTLGYGDKSF | ||||||
Transmembrane | 251-271 | Helical | ||||
Sequence: LFAVFWILTSSICLAQFFLYV | ||||||
Topological domain | 272-363 | Cytoplasmic | ||||
Sequence: AELNTENKQRALVKWVLTRRITNNDLEAADLDEDGVVGAAEFIVYKLKEMGKIDEKDISGIMDEFEQLDYDESGTLTTSDIVLAQTTSQIQR |
Keywords
- Cellular component
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.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Mutagenesis | 42 | Loss of interaction with GRF6, but no effect on vacuolar targeting. | ||||
Sequence: S → A | ||||||
Mutagenesis | 296-298 | Retention in the endoplasmic reticulum. | ||||
Sequence: DLE → GLG | ||||||
Mutagenesis | 301-303 | No effect on vacuolar targeting. | ||||
Sequence: DLD → GLG |
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.
PTM/Processing
Features
Showing features for chain.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Chain | PRO_0000101775 | 1-363 | Two-pore potassium channel 1 | |||
Sequence: MSSDAARTPLLPTEKIDTMAQDFNLNSRTSSSRKRRLRRSRSAPRGDCMYNDDVKIDEPPPHPSKIPMFSDLNPNLRRVIMFLALYLTIGTLCFYLVRDQISGHKTSGVVDALYFCIVTMTTVGYGDLVPNSSASRLLACAFVFSGMVLVGHLLSRAADYLVEKQEALLVRAFHLRQSFGPTDILKELHTNKLRYKCYATCLVLVVLFIVGTIFLVMVEKMPVISAFYCVCSTVTTLGYGDKSFNSEAGRLFAVFWILTSSICLAQFFLYVAELNTENKQRALVKWVLTRRITNNDLEAADLDEDGVVGAAEFIVYKLKEMGKIDEKDISGIMDEFEQLDYDESGTLTTSDIVLAQTTSQIQR |
Post-translational modification
Phosphorylation at Ser-42 increases and stabilizes the interaction with 14-3-3 proteins.
Keywords
- PTM
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
Structure
Family & Domains
Features
Showing features for region, compositional bias, domain, motif.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Region | 1-61 | Disordered | ||||
Sequence: MSSDAARTPLLPTEKIDTMAQDFNLNSRTSSSRKRRLRRSRSAPRGDCMYNDDVKIDEPPP | ||||||
Compositional bias | 42-60 | Basic and acidic residues | ||||
Sequence: SAPRGDCMYNDDVKIDEPP | ||||||
Domain | 288-323 | EF-hand 1 | ||||
Sequence: LTRRITNNDLEAADLDEDGVVGAAEFIVYKLKEMGK | ||||||
Motif | 296-298 | Endoplasmic reticulum release signal | ||||
Sequence: DLE | ||||||
Domain | 327-362 | EF-hand 2 | ||||
Sequence: KDISGIMDEFEQLDYDESGTLTTSDIVLAQTTSQIQ |
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
Belongs to the two pore domain potassium channel (TC 1.A.1.7) family.
Keywords
- Domain
Phylogenomic databases
Family and domain databases
Sequence
- Sequence statusComplete
- Length363
- Mass (Da)40,727
- Last updated2003-11-28 v2
- Checksum149B00AABBE40EFC
Features
Showing features for compositional bias, sequence conflict.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Compositional bias | 42-60 | Basic and acidic residues | ||||
Sequence: SAPRGDCMYNDDVKIDEPP | ||||||
Sequence conflict | 227 | in Ref. 7; AAM64705 | ||||
Sequence: F → V | ||||||
Sequence conflict | 261 | in Ref. 1; CAA65988 and 3; CAA69158 | ||||
Sequence: S → T |
Keywords
- Technical term
Sequence databases
Nucleotide Sequence | Protein Sequence | Molecule Type | Status | |
---|---|---|---|---|
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 |