Distinct roles of the last transmembrane domain in controlling Arabidopsis K+ channel activity

Pawel Gajdanowicz, Carlos Garcia-Mata, Wendy Gonzalez, Samuel Elías Morales-Navarro, Tripti Sharma, Fernando Danilo González-Nilo, Jan Gutowicz, Bernd Mueller-Roeber, Michael R. Blatt, Ingo Dreyer

Resultado de la investigación: Contribución a una revistaArtículorevisión exhaustiva

28 Citas (Scopus)

Resumen

The family of voltage-gated potassium channels in plants presumably evolved from a common ancestor and includes both inward-rectifying (Kin) channels that allow plant cells to accumulate K+ and outward-rectifying (Kout) channels that mediate K+ efflux. Despite their close structural similarities, the activity of Kin channels is largely independent of K+ and depends only on the transmembrane voltage, whereas that of Kout channels responds to the membrane voltage and the prevailing extracellular K+ concentration. Gating of potassium channels is achieved by structural rearrangements within the last transmembrane domain (S6). Here we investigated the functional equivalence of the S6 helices of the Kin channel KAT1 and the Kout channel SKOR by domain-swapping and site-directed mutagenesis. Channel mutants and chimeras were analyzed after expression in Xenopus oocytes. We identified two discrete regions that influence gating differently in both channels, demonstrating a lack of functional complementarity between KAT1 and SKOR. Our findings are supported by molecular models of KAT1 and SKOR in the open and closed states. The role of the S6 segment in gating evolved differently during specialization of the two channel subclasses, posing an obstacle for the transfer of the K+-sensor from Kout to Kin channels.

Idioma originalInglés
Páginas (desde-hasta)380-391
Número de páginas12
PublicaciónNew Phytologist
Volumen182
N.º2
DOI
EstadoPublicada - abr 2009

Áreas temáticas de ASJC Scopus

  • Fisiología
  • Botánica

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