Evolution and Structural Characteristics of Plant Voltage-Gated K⁺ Channels

Abstract

Plant voltage-gated K + channels have been referred to as "plant Shakers" in reference to animal Shaker channels, the first K + channels identified. Recent advances in our knowledge of K + channel evolution and structure have significantly deepened the divide between these plant and animal K + channels, suggesting that it is time to completely retire the "plant Shaker" designation. Evolutionary genomics reveals that plant voltage-gated K + channels and metazoan Shakers derive from distinct prokaryotic ancestors. The plant channels belong to a lineage that includes cyclic nucleotide-gated channels and metazoan ether-à-go-go and hyperpolarization-activated, cyclic nucleotide-gated channels. We refer to this lineage as the CNBD channel superfamily, because all these channels share a cytoplasmic gating domain homologous to cyclic nucleotide binding domains. The first structures of CNBD superfamily channels reveal marked differences in coupling between the voltage sensor and ion-conducting pore relative to metazoan Shaker channels. Viewing plant voltage-gated K + channel function through the lens of CNBD superfamily structures should lead to insights into how these channels are regulated.

Phosphatidic acid directly binds with rice potassium channel OsAKT2 to inhibit its activity

“…Plant K + uptake and allocation are mediated by a variety of K + channels and transporters, among which the best characterized family is that of the Shaker‐like K + channels (also named plant voltage‐gated K + channels) (Dreyer and Uozumi, 2011; Véry et al , 2014; Jegla et al , 2018). In the model plant Arabidopsis thaliana , the Shaker family member AtAKT2 is characterized as a weakly rectifying K + channel that can conduct K + in both inward and outward directions.…”

Diversity of voltage-gated potassium channels and cyclic nucleotide-binding domain-containing channels in eukaryotes

“…This observation may be rooted in both the complex evolutionary history (e.g., horizontal gene transfer, high rate of evolution) of these proteins and the scarcity of available data. Recently, Jegla et al 16 analysed the phylogeny of the plant voltage-gated potassium channels which turned out to be a part of CNBD-channels and proposed that the eukaryotic CNBD-channels are a result of an HGT from bacteria to eukaryotes. The HGT hypothesis is supported by the fact that there is still no evidence of CNBD-channels in archaea.…”

“…In plants, CNGC channels are implicated in the calcium entry and pathogen defense response, and potassium-selective 'K v -like' channels participate in stomatal closure (GORK channel) and potassium transport in xylem (SKOR channel) 15 . Both plant CNGC and 'K v -like' channels are now should be considered as CNBD-channels 16 .…”

Genomics-assisted prediction of salt and alkali tolerances and functional marker development in apple rootstocks.

“…KCAB interacts with speci c alpha-subunits to modify their expression or kinetics [74]. A limited number of studies have been conducted on plant voltage-gated K+ channels; therefore, knowledge about these potassium channels are lagging far behind similar studies in animals [75]. We found that the linked allelic variations of MdKCAB SNP11G and SNP761A could alter an amino acid residue at the Kv_beta domain of the peptide, contributing to an increase in salt, alkali, and salt-alkali tolerance in both apple plants and transgenic calli.…”