{PDOC51490}
{PS51490; KHA}
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* KHA domain profile *
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Potassium channels   take  part  in  important  processes  of  higher  plants,
including opening  and  closing  of  stomatal  pores and leaf movement. Inward
rectifying potassium  (K(+)in)  channels  play  an  important  role  in turgor
regulation and  ion  uptake in higher plants. All of them comprise, from their
N-terminal to their C-terminal ends: a short hydrophilic region, a hydrophobic
region structurally  analogous  and  partially homologous to the transmembrane
domain of  voltage-gated  animal  channels  from  the  Shaker  superfamily,  a
putative cyclic  nucleotide-binding  domain (see <PDOC00691>), and a conserved
C-terminal KHA  domain.  Between  these  last two regions, some of them (AKT1,
AKT2 and  SKT1)  contain  an  ankyrin-repeat domain (see <PDOC50088>) with six
repeats homologous  to  those  of human erythrocyte ankyrin. The KHA domain is
unique to  plant  K(+)in  channels.  The KHA domain contains two high-homology
blocks enriched  for  hydrophobic  and  acidic residues, respectively. The KHA
domain is  essential  for interaction of plant K(+)in channels. The KHA domain
mediates tetramerization and/or stabilization of the heteromers [1,2,3].

Some proteins known to contain a KHA domain are listed below:

 - Arabidopsis thaliana AKT1.
 - Arabidopsis thaliana AKT2/3.
 - Arabidopsis thaliana KAT1.
 - Arabidopsis thaliana KAT2.
 - Potato KST1.
 - Potato SKT1.
 - Potato SKT2.
 - Potato SKT3.

The profile we developed covers the entire KHA domain.

-Sequences known to belong to this class detected by the profile: ALL.
-Other sequence(s) detected in Swiss-Prot: NONE.
-Last update: April 2010 / First entry.

[ 1] Ehrhardt T., Zimmermann S., Mueller-Roeber B.
     "Association of plant K+(in) channels is mediated by conserved
     C-termini and does not affect subunit assembly."
     FEBS Lett. 409:166-170(1997).
     PubMed=9202139
[ 2] Daram P., Urbach S., Gaymard F., Sentenac H., Cherel I.
     "Tetramerization of the AKT1 plant potassium channel involves its
     C-terminal cytoplasmic domain."
     EMBO J. 16:3455-3463(1997).
     PubMed=9218788; DOI=10.1093/emboj/16.12.3455
[ 3] Zimmermann S., Hartje S., Ehrhardt T., Plesch G., Mueller-Roeber B.
     "The K+ channel SKT1 is co-expressed with KST1 in potato guard
     cells--both channels can co-assemble via their conserved KT domains."
     Plant J. 28:517-527(2001).
     PubMed=11849592

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