Switching between the two action modes of the dual-affinity nitrate transporter CHL1 by phosphorylation

To counteract fluctuating nutrient environments, plants have evolved high‐ and low‐affinity uptake systems. These two systems were traditionally thought to be genetically distinct, but, recently, two Arabidopsis transporters, AtKUP1 and CHL1, were shown to have dual affinities. However, little is kn...

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Bibliographic Details
Published in:The EMBO journal 2003-03, Vol.22 (5), p.1005-1013
Main Authors: Liu, Kun-Hsiang, Tsay, Yi-Fang
Format: Article
Language:English
Subjects:
affinity
Animals
Anion Transport Proteins - chemistry
Anion Transport Proteins - genetics
Anion Transport Proteins - metabolism
Arabidopsis
Arabidopsis - metabolism
Arabidopsis Proteins - chemistry
Arabidopsis Proteins - genetics
Arabidopsis Proteins - metabolism
Biological Transport
Cyclic AMP-Dependent Protein Kinases - antagonists & inhibitors
Cyclic AMP-Dependent Protein Kinases - chemistry
Cyclic AMP-Dependent Protein Kinases - metabolism
EMBO20
EMBO30
Mutagenesis, Site-Directed
nitrate
Nitrates
Nitrates - metabolism
Nitrogen - metabolism
Oocytes - cytology
Oocytes - physiology
Phosphorylation
Plant physiology
Plant Proteins
Plants, Genetically Modified
Threonine - metabolism
transporter
Xenopus laevis
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Summary:To counteract fluctuating nutrient environments, plants have evolved high‐ and low‐affinity uptake systems. These two systems were traditionally thought to be genetically distinct, but, recently, two Arabidopsis transporters, AtKUP1 and CHL1, were shown to have dual affinities. However, little is known about how a dual‐affinity transporter works and the advantages of having a dual‐affinity transporter. This study demonstrates that, in the case of CHL1, switching between the two modes of action is regulated by phosphorylation at threonine residue 101; when phosphorylated, CHL1 functions as a high‐affinity nitrate transporter, whereas, when dephosphorylated, it functions as a low‐affinity nitrate transporter. This regulatory mechanism allows plants to change rapidly between high‐ and low‐affinity nitrate uptake, which may be critical when competing for limited nitrogen. These results demonstrate yet another regulatory role of phosphorylation in plant physiology.
ISSN:0261-4189
1460-2075
DOI:10.1093/emboj/cdg118