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Phosphorylation influences water and ion channel function of AtPIP2;1
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  • Jiaen Qiu,
  • Samantha McGaughey,
  • Michael Groszmann,
  • Steve Tyerman,
  • Caitlin Byrt
Jiaen Qiu
University of Adelaide

Corresponding Author:jiaen.qiu@adelaide.edu.au

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Samantha McGaughey
Australian National University
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Michael Groszmann
Australian National University
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Steve Tyerman
University of Adelaide
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Caitlin Byrt
Australian National University
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The phosphorylation states of two serine residues within the C-terminal domain of AtPIP2;1 (S280, S283) regulate its trafficking to the plasma membrane in response to salt and osmotic stress. Here we investigated whether the phosphorylation states of S280 and S283 also influence AtPIP2;1 facilitated water and cation transport. A series of single and double S280 and S283 phospho-mimic and -deficient AtPIP2;1 mutants were tested in heterologous systems. In Xenopus laevis oocytes, phospho-mimic mutants AtPIP2;1 S280D, S283D and S280D/S283D, had significantly greater ion conductance for Na+ and K+, whereas the S280A single and S280A/S283A double mutants, had greater water permeability. A phospho-mimic-dependent inverse relationship between AtPIP2;1 water and ion transport with a 10-fold change in both was observed. These results revealed that phosphorylation of S280 and S283 influences the preferential facilitation between ion and water permeability by AtPIP2;1. The results also hint at other sites playing a role that are yet to be elucidated. Expression of the phospho-mimic AtPIP2;1 mutants in Saccharomyces cerevisiae, confirmed that phosphorylation influences plasma membrane localisation, and revealed higher Na+ accumulation for S280A and S283D. Collectively, the results show that phosphorylation in the C-terminal domain of AtPIP2;1 influences its subcellular localisation and cation transport capacity.
22 May 2020Submitted to Plant, Cell & Environment
22 May 2020Submission Checks Completed
22 May 2020Assigned to Editor
22 May 2020Reviewer(s) Assigned
13 Jun 2020Review(s) Completed, Editorial Evaluation Pending
13 Jun 2020Editorial Decision: Revise Minor
09 Jul 20201st Revision Received
09 Jul 2020Submission Checks Completed
09 Jul 2020Assigned to Editor
09 Jul 2020Review(s) Completed, Editorial Evaluation Pending
09 Jul 2020Editorial Decision: Accept
Oct 2020Published in Plant, Cell & Environment volume 43 issue 10 on pages 2428-2442. 10.1111/pce.13851