Outward potassium channel in stomata / PLANT PROTEIN
機能・相同性
機能・相同性情報
monoatomic ion transmembrane transporter activity / response to jasmonic acid / response to abscisic acid / response to water deprivation / outward rectifier potassium channel activity / monoatomic ion channel complex / monoatomic ion transport / response to cold / response to calcium ion / nucleus 類似検索 - 分子機能
Japan Agency for Medical Research and Development (AMED)
日本
引用
ジャーナル: Proc Natl Acad Sci U S A / 年: 2025 タイトル: Structure reveals a regulation mechanism of plant outward-rectifying K channel GORK by structural rearrangements in the CNBD-Ankyrin bridge. 著者: Taro Yamanashi / Yuki Muraoka / Tadaomi Furuta / Tsukasa Kume / Natsuko Sekido / Shunya Saito / Shota Terashima / Takeshi Yokoyama / Yoshikazu Tanaka / Atsushi Miyamoto / Kanane Sato / ...著者: Taro Yamanashi / Yuki Muraoka / Tadaomi Furuta / Tsukasa Kume / Natsuko Sekido / Shunya Saito / Shota Terashima / Takeshi Yokoyama / Yoshikazu Tanaka / Atsushi Miyamoto / Kanane Sato / Tomoyuki Ito / Hikaru Nakazawa / Mitsuo Umetsu / Ellen Tanudjaja / Masaru Tsujii / Ingo Dreyer / Julian I Schroeder / Yasuhiro Ishimaru / Nobuyuki Uozumi / 要旨: Guard cells, which regulate stomatal apertures in plants, possess a sophisticated mechanism for regulating turgor pressure. The outward-rectifying "K" channel GORK, expressed in guard cells of the ...Guard cells, which regulate stomatal apertures in plants, possess a sophisticated mechanism for regulating turgor pressure. The outward-rectifying "K" channel GORK, expressed in guard cells of the plant , is a central component that promotes stomatal closure by releasing K to the extracellular space, thereby lowering turgor pressure. To date, the structural basis underlying the regulation of the K transport activity of GORK is unclear. Using cryo-EM, we determined the structures of the GORK outward-rectifying K channel with a resolution of 3.16 to 3.27 Å in five distinct conformations that differ significantly in their C-terminal cyclic nucleotide binding domain (CNBD) and ankyrin repeat (ANK) domain. The C-linker connects the transmembrane domains to the C-terminal domains, i.e., CNBD, CNBD-Ankyrin bridge, and ANK. The structural changes and interactions in the C-linker determine whether the closed state of GORK is closer to the preopen state or in a more removed state from the open state of the channel. In particular, interconversion in the short sequence within the CNBD-Ankyrin bridge plays a decisive role in this determination. This region forms an α-helix in the preopened state, while it adopts a nonhelical structure in further distant closed states. The dynamics of the cytosolic region strongly suggest that the K channel activity of GORK is regulated by cytosolic signaling factors during stomatal closure.