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Title | Structural basis for the activity regulation of a potassium channel AKT1 from Arabidopsis. |
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Journal, issue, pages | Nat Commun, Vol. 13, Issue 1, Page 5682, Year 2022 |
Publish date | Sep 27, 2022 |
Authors | Yaming Lu / Miao Yu / Yutian Jia / Fan Yang / Yanming Zhang / Xia Xu / Xiaomin Li / Fan Yang / Jianlin Lei / Yi Wang / Guanghui Yang / |
PubMed Abstract | The 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 ...The 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 α-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. |
External links | Nat Commun / PubMed:36167696 / PubMed Central |
Methods | EM (single particle) |
Resolution | 2.9 - 3.4 Å |
Structure data | EMDB-31532, PDB-7fcv: EMDB-32769, PDB-7wsw: EMDB-33467, PDB-7xuf: |
Chemicals | ChemComp-PTY: ChemComp-K: |
Source |
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Keywords | PLANT PROTEIN / Complex / Potassium channel / Membrane protein |