Aquaporin Tetramer Composition Modifies the Function of Tobacco Aquaporins

Heterologous expression in yeast cells revealed that NtAQP1, a member of the so-called PIP1 aquaporin subfamily, did not display increased water transport activity in comparison with controls. Instead, an increased CO2-triggered intracellular acidification was observed. NtPIP2;1, which belongs to th...

Full description

Saved in:
Bibliographic Details
Published in:The Journal of biological chemistry 2010-10, Vol.285 (41), p.31253-31260
Main Authors: Otto, Beate, Uehlein, Norbert, Sdorra, Sven, Fischer, Matthias, Ayaz, Muhammad, Belastegui-Macadam, Xana, Heckwolf, Marlies, Lachnit, Magdalena, Pede, Nadine, Priem, Nadine, Reinhard, André, Siegfart, Sven, Urban, Michael, Kaldenhoff, Ralf
Format: Article
Language:English
Subjects:
Aquaporin Tetramer
Aquaporins - genetics
Aquaporins - metabolism
Carbon Dioxide
Carbon Dioxide - metabolism
Cell Biology
Cell Membrane Permeability - physiology
Fluorescence
Membrane
Membrane Biology
Nicotiana - genetics
Nicotiana - metabolism
Plant PIP
Plant Proteins - genetics
Plant Proteins - metabolism
Protein Structure, Quaternary
Protein-Protein Interactions
Saccharomyces cerevisiae
Water - metabolism
Water Channel
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Heterologous expression in yeast cells revealed that NtAQP1, a member of the so-called PIP1 aquaporin subfamily, did not display increased water transport activity in comparison with controls. Instead, an increased CO2-triggered intracellular acidification was observed. NtPIP2;1, which belongs to the PIP2 subfamily of plant aquaporins, behaved as a true aquaporin but lacked a CO2-related function. Results from split YFP experiments, protein chromatography, and gel electrophoresis indicated that the proteins form heterotetramers when coexpressed in yeast. Tetramer composition had effects on transport activity as demonstrated by analysis of artificial heterotetramers with a defined proportion of NtAQP1 to NtPIP2;1. A single NtPIP2;1 aquaporin in a tetramer was sufficient to significantly increase the water permeability of the respective yeast cells. With regard to CO2-triggered intracellular acidification, a cooperative effect was observed, where maximum rates were measured when the tetramer consisted of NtAQP1 aquaporins only. The results confirm the model of an aquaporin monomer as a functional unit for water transport and suggest that, for CO2-related transport processes, a structure built up by the tetramer is the basis of this function.
ISSN:0021-9258
1083-351X
DOI:10.1074/jbc.M110.115881