Please use this identifier to cite or link to this item:
Scopus Web of Science® Altmetric
Type: Journal article
Title: A single residue deletion in the barley HKT1;5 P189 variant restores plasma membrane localisation but not Na⁺ conductance
Other Titles: A single residue deletion in the barley HKT1;5 P189 variant restores plasma membrane localisation but not Na+ conductance
Author: Wege, S.
Qiu, J.
Byrt, C.
Houston, K.
Waugh, R.
Gilliham, M.
Hrmova, M.
Citation: BBA: Biomembranes, 2021; 1863(10):183669-1-183669-11
Publisher: Elsevier BV
Issue Date: 2021
ISSN: 0005-2736
Statement of
Stefanie Wege, Jiaen Qiu, Caitlin Byrt, Kelly Houston, Robbie Waugh, Matthew Gilliham, Maria Hrmova
Abstract: Leaf Na⁺ exclusion, mediated by plasma membrane-localised Class 1 High-affinity potassium (K⁺) Transporters (HKTs), is a key mechanism contributing to salinity tolerance of several major crop plants. We determined previously that the leucine to proline residue substitution at position 189 (L189P) in barley HvHKT1;5 disrupts its characteristic plasma membrane localisation and Na⁺ conductance. Here, we focus on a surprising observation that a single residue deletion of methionine at position 372 (M372del) within the conserved VMMYL motif in plant HKTs, restores plasma membrane localisation but not Na⁺ conductance in HvHKT1;5 P189. To clarify why the singular M372 deletion regains plasma membrane localisation, we built 3D models and defined α-helical assembly pathways of the P189 M372del mutant, and compared these findings to the wild-type protein, and the HvHKT1;5 L189 variant and its M372del mutant. We find that α-helical association and assembly pathways in HvHKT1;5 proteins fall in two contrasting categories. Inspections of structural flexibility through molecular dynamics simulations revealed that the conformational states of HvHKT1;5 P189 diverge from those of the L189 variant and M372del mutants. We propose that M372del in HvHKT1;5 P189 instigates structural rearrangements allowing routing to the plasma membrane, while the restoration of conductance would require further interventions. We integrate the microscopy, electrophysiology, and biocomputational data and discuss how a profound structural change in HvHKT1;5 P189 M372del impacts its α-helical protein association pathway and flexibility, and how these features underlie a delicate balance leading to restoring plasma membrane localisation but not Na⁺ conductance.
Keywords: 3D protein modelling; α-Helical association and assembly pathways; Confocal microscopy; Molecular dynamics simulations; Salinity; Two-Electrode Voltage-Clamp
Description: Available online 15 June 2021
Rights: © 2021 Elsevier B.V. All rights reserved.
DOI: 10.1016/j.bbamem.2021.183669
Grant ID:
Published version:
Appears in Collections:Agriculture, Food and Wine publications
Aurora harvest 4

Files in This Item:
File Description SizeFormat 
hdl_131431.pdfAccepted version9.74 MBAdobe PDFView/Open

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.