title: K₂p channels in plants and animals.
abstract: Two-pore domain potassium (K2P) channels are membrane proteins widely identified in mammals, plants, and other organisms. A functional channel is a dimer with each subunit comprising two pore-forming loops and four transmembrane domains. The genome of the model plant Arabidopsis thaliana harbors five genes coding for K2P channels. Homologs of Arabidopsis K2P channels have been found in all higher plants sequenced so far. As with the K2P channels in mammals, plant K2P channels are targets of external and internal stimuli, which fine-tune the electrical properties of the membrane for specialized transport and/or signaling tasks. Plant K2P channels are modulated by signaling molecules such as intracellular H(+) and calcium and physical factors like temperature and pressure. In this review, we ask the following: What are the similarities and differences between K2P channels in plants and animals in terms of their physiology? What is the nature of the last common ancestor (LCA) of these two groups of proteins? To answer these questions, we present physiological, structural, and phylogenetic evidence that discards the hypothesis proposing that the duplication and fusion that gave rise to the K2P channels occurred in a prokaryote LCA. Conversely, we argue that the K2P LCA was most likely a eukaryote organism. Consideration of plant and animal K2P channels in the same study is novel and likely to stimulate further exchange of ideas between students of these fields.
authors.affiliation: Centro de Bioinformática y Simulación Molecular (CBSM), Universidad de Talca, 2 Norte 685, Talca, Chile, wgonzalez@utalca.cl.
authors.forename: Wendy
authors.initials: W
authors.lastname: González
authors.forename: Braulio
authors.initials: B
authors.lastname: Valdebenito
authors.forename: Julio
authors.initials: J
authors.lastname: Caballero
authors.forename: Gonzalo
authors.initials: G
authors.lastname: Riadi
authors.forename: Janin
authors.initials: J
authors.lastname: Riedelsberger
authors.forename: Gonzalo
authors.initials: G
authors.lastname: Martínez
authors.forename: David
authors.initials: D
authors.lastname: Ramírez
authors.forename: Leandro
authors.initials: L
authors.lastname: Zúñiga
authors.forename: Francisco V
authors.initials: FV
authors.lastname: Sepúlveda
authors.forename: Ingo
authors.initials: I
authors.lastname: Dreyer
authors.forename: Michael
authors.initials: M
authors.lastname: Janta
authors.forename: Dirk
authors.initials: D
authors.lastname: Becker
mesh_terms: D000818:Animals; D006801:Humans; D006863:Hydrogen-Ion Concentration; D010802:Phylogeny; D010944:Plants; D011188:Potassium / Q000378:metabolism*; D024683:Potassium Channels, Tandem Pore Domain / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*
chemical_list: D024683:Potassium Channels, Tandem Pore Domain; D011188:Potassium