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1.A.1.4.6
Heterotetrameric K+ channel, KAT2/AKT2/KCT2 (Nieves-Cordones et al. 2014). Forms heteromeric channels (2:2 stoichiometry) with KAT1 (1.A.1.4.7) (Lebaudy et al., 2010) (Properties differ from those of homomeric channels; Xicluna et al., 2007).  KAT2 also forms homomeric channels in the plasma membrane (Nieves-Cordones et al. 2014). AKT2 functions in phloem loading and unloading and operates as an inward-rectifying channel that allows H+-ATPase-energized K+ uptake. Through reversible post-translational modifications, it can also function as an open, K+-selective channel, providing energy for transmembrane transport processes. It is present in a complex of several proteins in which it interacts with the receptor-like kinase, MRH1/MDIS2 (Sklodowski et al. 2017). The ortholog in Brassica rapa (Chinese cabbage), KCT2, is induced by stress. It has a TxxTxGYGD motif in the P-domain and a putative cyclic nucleotide-binding-like domain within a long C-terminal region (Zhang et al. 2006).  

Accession Number:Q38898
Protein Name:AKT2 aka AKT2/3
Length:802
Molecular Weight:91308.00
Species:Arabidopsis thaliana (Mouse-ear cress) [3702]
Number of TMSs:7
Location1 / Topology2 / Orientation3: Membrane1 / Multi-pass membrane protein2
Substrate K+

Cross database links:

Genevestigator: Q38898
eggNOG: KOG0498
HEGENOM: HBG318539
RefSeq: NP_567651.1   
Entrez Gene ID: 828311   
Pfam: PF00023    PF00027    PF11834    PF00520   
KEGG: ath:AT4G22200   

Gene Ontology

GO:0016021 C:integral to membrane
GO:0042802 F:identical protein binding
GO:0005249 F:voltage-gated potassium channel activity
GO:0006813 P:potassium ion transport
GO:0042391 P:regulation of membrane potential
GO:0055085 P:transmembrane transport

References (12)

[1] “Multiple genes, tissue specificity, and expression-dependent modulation contribute to the functional diversity of potassium channels in Arabidopsis thaliana.”  Cao Y.et.al.   8552711
[2] “Isolation of an ion channel gene from Arabidopsis thaliana using the H5 signature sequence from voltage-dependent K+ channels.”  Ketchum K.A.et.al.   8549795
[3] “Sequence and analysis of chromosome 4 of the plant Arabidopsis thaliana.”  Mayer K.F.X.et.al.   10617198
[4] “AKT3, a phloem-localized K+ channel, is blocked by protons.”  Marten I.et.al.   10377458
[5] “Suppression of inward-rectifying K+ channels KAT1 and AKT2 by dominant negative point mutations in the KAT1 alpha-subunit.”  Baizabal-Aguirre V.M.et.al.   9916143
[6] “A shaker-like K(+) channel with weak rectification is expressed in both source and sink phloem tissues of Arabidopsis.”  Lacombe B.et.al.   10852932
[7] “The AKT3 potassium channel protein interacts with the AtPP2CA protein phosphatase 2C.”  Vranova E.et.al.   11181729
[8] “Phylogenetic relationships within cation transporter families of Arabidopsis.”  Maeser P.et.al.   11500563
[9] “Loss of the AKT2/3 potassium channel affects sugar loading into the phloem of Arabidopsis.”  Deeken R.et.al.   12447548
[10] “Physical and functional interaction of the Arabidopsis K(+) channel AKT2 and phosphatase AtPP2CA.”  Cherel I.et.al.   12034902
[11] “Outer pore residues control the H(+) and K(+) sensitivity of the Arabidopsis potassium channel AKT3.”  Geiger D.et.al.   12172027
[12] “Regulated expression of Arabidopsis shaker K(+) channel genes involved in K(+) uptake and distribution in the plant.”  Pilot G.et.al.   12678562

External Searches:

  • Search: DB with
  • BLAST ExPASy (Swiss Institute of Bioinformatics (SIB) BLAST)
  • CDD Search (Conserved Domain Database)
  • Search COGs (Clusters of Orthologous Groups of proteins)
  • 2° Structure (Network Protein Sequence Analysis)

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Predict TMSs (Predict number of transmembrane segments)
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FASTA formatted sequence
1:	MDLKYSASHC NLSSDMKLRR FHQHRGKGRE EEYDASSLSL NNLSKLILPP LGVASYNQNH 
61:	IRSSGWIISP MDSRYRCWEF YMVLLVAYSA WVYPFEVAFL NSSPKRNLCI ADNIVDLFFA 
121:	VDIVLTFFVA YIDERTQLLV REPKQIAVRY LSTWFLMDVA STIPFDAIGY LITGTSTLNI 
181:	TCNLLGLLRF WRLRRVKHLF TRLEKDIRYS YFWIRCFRLL SVTLFLVHCA GCSYYLIADR 
241:	YPHQGKTWTD AIPNFTETSL SIRYIAAIYW SITTMTTVGY GDLHASNTIE MVFITVYMLF 
301:	NLGLTAYLIG NMTNLVVEGT RRTMEFRNSI EAASNFVNRN RLPPRLKDQI LAYMCLRFKA 
361:	ESLNQQHLID QLPKSIYKSI CQHLFLPSVE KVYLFKGVSR EILLLLVSKM KAEYIPPRED 
421:	VIMQNEAPDD VYIIVSGEVE IIDSEMERES VLGTLRCGDI FGEVGALCCR PQSYTFQTKS 
481:	LSQLLRLKTS FLIETMQIKQ QDNATMLKNF LQHHKKLSNL DIGDLKAQQN GENTDVVPPN 
541:	IASNLIAVVT TGNAALLDEL LKAKLSPDIT DSKGKTPLHV AASRGYEDCV LVLLKHGCNI 
601:	HIRDVNGNSA LWEAIISKHY EIFRILYHFA AISDPHIAGD LLCEAAKQNN VEVMKALLKQ 
661:	GLNVDTEDHH GVTALQVAMA EDQMDMVNLL ATNGADVVCV NTHNEFTPLE KLRVVEEEEE 
721:	EERGRVSIYR GHPLERRERS CNEAGKLILL PPSLDDLKKI AGEKFGFDGS ETMVTNEDGA 
781:	EIDSIEVIRD NDKLYFVVNK II