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Cryo-EM structure of the AKT1-AtKC1 complex from Arabidopsis thalianaCryo-EM structure of the AKT1-AtKC1 complex from Arabidopsis thaliana
Structural highlights
FunctionKAT3_ARATH Probable modulatory (alpha) subunit of inward-rectifying potassium channels. Could mediate potassium uptake from the soil solution by plant roots in association with AKT1.[1] [2] Publication Abstract from PubMedThe voltage-gated potassium channel AKT1 is responsible for primary K(+) uptake in Arabidopsis roots. AKT1 is functionally activated through phosphorylation and negatively regulated by a potassium channel alpha-subunit AtKC1. However, the molecular basis for the modulation mechanism remains unclear. Here we report the structures of AKT1, phosphorylated-AKT1, a constitutively-active variant, and AKT1-AtKC1 complex. AKT1 is assembled in 2-fold symmetry at the cytoplasmic domain. Such organization appears to sterically hinder the reorientation of C-linkers during ion permeation. Phosphorylated-AKT1 adopts an alternate 4-fold symmetric conformation at cytoplasmic domain, which indicates conformational changes associated with symmetry switch during channel activation. To corroborate this finding, we perform structure-guided mutagenesis to disrupt the dimeric interface and identify a constitutively-active variant Asp379Ala mediates K(+) permeation independently of phosphorylation. This variant predominantly adopts a 4-fold symmetric conformation. Furthermore, the AKT1-AtKC1 complex assembles in 2-fold symmetry. Together, our work reveals structural insight into the regulatory mechanism for AKT1. Structural basis for the activity regulation of a potassium channel AKT1 from Arabidopsis.,Lu Y, Yu M, Jia Y, Yang F, Zhang Y, Xu X, Li X, Yang F, Lei J, Wang Y, Yang G Nat Commun. 2022 Sep 27;13(1):5682. doi: 10.1038/s41467-022-33420-8. PMID:36167696[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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