PROSITE documentation PDOC51490

KHA domain profile

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.