Premium
Switching between the two action modes of the dual‐affinity nitrate transporter CHL1 by phosphorylation
Author(s) -
Liu KunHsiang,
Tsay YiFang
Publication year - 2003
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/cdg118
Subject(s) - transporter , phosphorylation , biology , biochemistry , threonine , nitrate , microbiology and biotechnology , arabidopsis , affinities , gene , serine , ecology , mutant
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.