Hydrophobic pore gates regulate ion permeation in polycystic kidney disease 2 and 2L1 channels.

Zheng, Wang; Yang, Xiaoyong; Hu, Ruikun; Cai, Ruiqi; Hofmann, Laura; Wang, Zhifei; Hu, Qiaolin; Liu, Xiong et al. · Nat Commun · 2018

basic_science · Level V

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Abstract

PKD2 and PKD1 genes are mutated in human autosomal dominant polycystic kidney disease. PKD2 can form either a homomeric cation channel or a heteromeric complex with the PKD1 receptor, presumed to respond to ligand(s) and/or mechanical stimuli. Here, we identify a two-residue hydrophobic gate in PKD2L1, and a single-residue hydrophobic gate in PKD2. We find that a PKD2 gain-of-function gate mutant effectively rescues PKD2 knockdown-induced phenotypes in embryonic zebrafish. The structure of a PKD2 activating mutant F604P by cryo-electron microscopy reveals a π- to α-helix transition within the pore-lining helix S6 that leads to repositioning of the gate residue and channel activation. Overall the results identify hydrophobic gates and a gating mechanism of PKD2 and PKD2L1.

Medical subject headings