Please use this identifier to cite or link to this item:
https://hdl.handle.net/2440/131431
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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 1879-2642 |
Statement of Responsibility: | 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: | http://purl.org/au-research/grants/arc/CE140100008 http://purl.org/au-research/grants/arc/DE160100804 http://purl.org/au-research/grants/arc/FT180100476 http://purl.org/au-research/grants/arc/DP120100900 |
Published version: | http://dx.doi.org/10.1016/j.bbamem.2021.183669 |
Appears in Collections: | Agriculture, Food and Wine publications Aurora harvest 4 |
Files in This Item:
File | Description | Size | Format | |
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hdl_131431.pdf | Accepted version | 9.74 MB | Adobe PDF | View/Open |
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