9LA1

Arabidopsis GORK WT4

Summary for 9LA1

• Entry DOI: 10.2210/pdb9la1/pdb
• Related: 9L9U 9LA0
• EMDB information: 62916
• Descriptor: Potassium channel GORK (1 entity in total)
• Functional Keywords: outward potassium channel in stomata, plant protein
• Biological source: Arabidopsis thaliana (thale cress)
• Total number of polymer chains: 4
• Total formula weight: 385637.38

Authors

Yamanashi, T.,Kume, T.,Sekido, N.,Muraoka, Y.,Yokoyama, T.,Tanaka, Y.,Uozumi, N. (deposition date: 2025-01-01, release date: 2025-07-16, Last modification date: 2025-08-06)

Primary citation

Yamanashi, T.,Muraoka, Y.,Furuta, T.,Kume, T.,Sekido, N.,Saito, S.,Terashima, S.,Yokoyama, T.,Tanaka, Y.,Miyamoto, A.,Sato, K.,Ito, T.,Nakazawa, H.,Umetsu, M.,Tanudjaja, E.,Tsujii, M.,Dreyer, I.,Schroeder, J.I.,Ishimaru, Y.,Uozumi, N.
Structure reveals a regulation mechanism of plant outward-rectifying K + channel GORK by structural rearrangements in the CNBD-Ankyrin bridge.
Proc.Natl.Acad.Sci.USA, 122:e2500070122-e2500070122, 2025

PubMed Abstract: 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.

PubMed: 40699930
DOI: 10.1073/pnas.2500070122

Experimental method

ELECTRON MICROSCOPY (3.15 Å)