InterPro domain: IPR021789

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, and a conserved C-terminal KHA domain. Between these last two regions, some of them (AKT1, AKT2 and SKT1) contain an ankyrin-repeat domain with six repeats homologous to those of human erythrocyte ankyrin.

This entry represents the KHA domain which 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 stabilisation of the heteromers [ 1 , 2 , 3 ].

1. Association of plant K+(in) channels is mediated by conserved C-termini and does not affect subunit assembly. FEBS Lett. 409, 166-70
2. Tetramerization of the AKT1 plant potassium channel involves its C-terminal cytoplasmic domain. EMBO J. 16, 3455-63
3. 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, 517-27