7XUF

Cryo-EM structure of the AKT1-AtKC1 complex from Arabidopsis thaliana

Summary for 7XUF

• Entry DOI: 10.2210/pdb7xuf/pdb
• EMDB information: 33467
• Descriptor: Potassium channel KAT3, Potassium channel AKT1, POTASSIUM ION (3 entities in total)
• Functional Keywords: complex, potassium channel, membrane protein
• Biological source: Arabidopsis thaliana (thale cress); More
• Total number of polymer chains: 4
• Total formula weight: 345712.59

Authors

Yang, G.H.,Lu, Y.M.,Jia, Y.T.,Yang, F.,Zhang, Y.M.,Xu, X.,Li, X.M.,Lei, J.L. (deposition date: 2022-05-18, release date: 2022-11-09, Last modification date: 2025-06-18)

Primary citation

Lu, Y.,Yu, M.,Jia, Y.,Yang, F.,Zhang, Y.,Xu, X.,Li, X.,Yang, F.,Lei, J.,Wang, Y.,Yang, G.
Structural basis for the activity regulation of a potassium channel AKT1 from Arabidopsis.
Nat Commun, 13:5682-5682, 2022

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 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.

PubMed: 36167696
DOI: 10.1038/s41467-022-33420-8

Experimental method

ELECTRON MICROSCOPY (3.3 Å)