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XB-ART-57912
Elife February 23, 2021; 10
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Molecular basis for functional connectivity between the voltage sensor and the selectivity filter gate in Shaker K+ channels.

Bassetto CA , Carvalho-de-Souza JL , Bezanilla F .


Abstract
In Shaker K+ channels, the S4-S5 linker couples the voltage sensor (VSD) and pore domain (PD). Another coupling mechanism is revealed using two W434F-containing channels: L361R:W434F and L366H:W434F. In L361R:W434F, W434F affects the L361R VSD seen as a shallower charge-voltage (Q-V) curve that crosses the conductance-voltage (G-V) curve. In L366H:W434F, L366H relieves the W434F effect converting a non-conductive channel in a conductive one. We report a chain of residues connecting the VSD (S4) to the selectivity filter (SF) in the PD of an adjacent subunit as the molecular basis for voltage sensor selectivity filter gate (VS-SF) coupling. Single alanine substitutions in this region (L409A, S411A, S412A, or F433A) are enough to disrupt the VS-SF coupling, shown by the absence of Q-V and G-V crossing in L361R:W434F mutant and by the lack of ionic conduction in the L366H:W434F mutant. This residue chain defines a new coupling between the VSD and the PD in voltage-gated channels.

PubMed ID: 33620313
PMC ID: PMC7943188
Article link: Elife
Grant support: [+]

Species referenced: Xenopus laevis
Genes referenced: kcna1
GO keywords: voltage-gated ion channel activity [+]


Article Images: [+] show captions
References [+] :
Aggarwal, Contribution of the S4 segment to gating charge in the Shaker K+ channel. 1996, Pubmed, Xenbase