9khf
AtGORK Full length 1
Structural highlights
FunctionGORK_ARATH Major selective outward-rectifying potassium channel of the guard cell membrane. Involved in regulation of stomatal movements according to the water status. Assuming opened or closed conformations in response to the voltage difference across the membrane, the channel is activated by depolarization. Conductance of the channel is modulated in a potassium-dependent fashion. May interact with the cytoskeleton or with regulatory proteins.[1] Publication Abstract from PubMedGORK is a shaker-like potassium channel in plants that contains ankyrin (ANK) repeats. In guard cells, activation of GORK causes K+ efflux, reducing turgor pressure and closing stomata. However, how GORK is regulated remains largely elusive. Here, we solved the cryo-EM structure of Arabidopsis GORK, revealing an unusual symmetry reduction (from C4 to C2) feature within its tetrameric assembly. This symmetry reduction in GORK channel is driven by ANK dimerization, which disrupts the coupling between transmembrane helices and cytoplasmic domains, thus maintaining GORK in an autoinhibited state. Electrophysiological and structural analyses further confirmed that ANK dimerization inhibits GORK, and its removal restores C4 symmetry, converting GORK to an activatable state. This dynamic switching between C2 and C4 symmetry, mediated by ANK dimerization, presents a GORK target site that guard cells regulate to switch the plant K+ channel between inhibited and activatable states, thus controlling stomatal movement in response to environmental stimuli. Structural and mechanistic insights into symmetry conversion in plant GORK K+ channel regulation.,Li QY, Qin L, Tang LH, Zhang CR, Huang S, Wang K, Zhang GH, Hao NJ, Xiao Q, Niu T, Su M, Hedrich R, Chen YH Protein Cell. 2025 Aug 3:pwaf067. doi: 10.1093/procel/pwaf067. PMID:40996076[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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