Premium
Phosphorylation influences water and ion channel function of AtPIP2;1
Author(s) -
Qiu Jiaen,
McGaughey Samantha A.,
Groszmann Michael,
Tyerman Stephen D.,
Byrt Caitlin S.
Publication year - 2020
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/pce.13851
Subject(s) - phosphorylation , xenopus , mutant , biophysics , serine , chemistry , microbiology and biotechnology , ion transporter , heterologous expression , subcellular localization , protein phosphorylation , water transport , biochemistry , membrane , biology , water flow , cytoplasm , protein kinase a , recombinant dna , gene , environmental engineering , engineering
The phosphorylation state of two serine residues within the C‐terminal domain of AtPIP2;1 (S280, S283) regulates its plasma membrane localization in response to salt and osmotic stress. Here, we investigated whether the phosphorylation state of S280 and S283 also influence AtPIP2;1 facilitated water and cation transport. A series of single and double S280 and S283 phosphomimic and phosphonull AtPIP2;1 mutants were tested in heterologous systems. In Xenopus laevis oocytes, phosphomimic mutants AtPIP2;1 S280D, S283D, and S280D/S283D had significantly greater ion conductance for Na + and K + , whereas the S280A single phosphonull mutant had greater water permeability. We observed a phosphorylation‐dependent inverse relationship between AtPIP2;1 water and ion transport with a 10‐fold change in both. The results revealed that phosphorylation of S280 and S283 influences the preferential facilitation of ion or water transport by AtPIP2;1. The results also hint that other regulatory sites play roles that are yet to be elucidated. Expression of the AtPIP2;1 phosphorylation mutants in Saccharomyces cerevisiae confirmed that phosphorylation influences plasma membrane localization, and revealed higher Na + accumulation for S280A and S283D mutants. Collectively, the results show that phosphorylation in the C‐terminal domain of AtPIP2;1 influences its subcellular localization and cation transport capacity.