A Survey of Barley PIP Aquaporin Ionic Conductance Reveals Ca2+-Sensitive HvPIP2;8 Na+ and K+ Conductance.
Int J Mol Sci
; 21(19)2020 09 27.
Article
in En
| MEDLINE
| ID: mdl-32992595
ABSTRACT
Some plasma membrane intrinsic protein (PIP) aquaporins can facilitate ion transport. Here we report that one of the 12 barley PIPs (PIP1 and PIP2) tested, HvPIP2;8, facilitated cation transport when expressed in Xenopus laevis oocytes. HvPIP2;8-associated ion currents were detected with Na+ and K+, but not Cs+, Rb+, or Li+, and was inhibited by Ba2+, Ca2+, and Cd2+ and to a lesser extent Mg2+, which also interacted with Ca2+. Currents were reduced in the presence of K+, Cs+, Rb+, or Li+ relative to Na+ alone. Five HvPIP1 isoforms co-expressed with HvPIP2;8 inhibited the ion conductance relative to HvPIP2;8 alone but HvPIP1;3 and HvPIP1;4 with HvPIP2;8 maintained the ion conductance at a lower level. HvPIP2;8 water permeability was similar to that of a C-terminal phosphorylation mimic mutant HvPIP2;8 S285D, but HvPIP2;8 S285D showed a negative linear correlation between water permeability and ion conductance that was modified by a kinase inhibitor treatment. HvPIP2;8 transcript abundance increased in barley shoot tissues following salt treatments in a salt-tolerant cultivar Haruna-Nijo, but not in salt-sensitive I743. There is potential for HvPIP2;8 to be involved in barley salt-stress responses, and HvPIP2;8 could facilitate both water and Na+/K+ transport activity, depending on the phosphorylation status.
Key words
Full text:
1
Database:
MEDLINE
Main subject:
Oocytes
/
Plant Proteins
/
Potassium
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Sodium
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Hordeum
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Calcium
/
Ion Transport
/
Plant Shoots
/
Aquaporins
Type of study:
Diagnostic_studies
Language:
En
Journal:
Int J Mol Sci
Year:
2020
Type:
Article
Affiliation country:
Japan