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Cytokinin signaling stabilizes the response activator ARR 1
Author(s) -
Kurepa Jasmina,
Li Yan,
Smalle Jan A.
Publication year - 2014
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.12458
Subject(s) - cytokinin , activator (genetics) , arabidopsis , signal transduction , microbiology and biotechnology , response regulator , biology , phosphorylation , regulation of gene expression , gene , biochemistry , mutant , auxin
Summary The cytokinins play essential roles in the development and environmental responses of higher plants. Cytokinin signaling leads to the phosphorylation‐dependent activation of two classes of Arabidopsis response regulators ( RR s): the type‐B RR ( RRB ) transcriptional activators that promote the expression of cytokinin response genes and the type‐A RR s ( RRA s) that are encoded by primary cytokinin response genes and function as response inhibitors. We show that cytokinin signaling increases the abundance of ARR 1, a ubiquitously expressed RRB , by preventing its degradation by the 26S proteasome. We also show that the RRA s act to suppress ARR 1 accumulation, thus providing an explanation for their inhibitory action in cytokinin signaling. Collectively, our results reveal an additional regulatory mechanism in the cytokinin response pathway that involves the cytokinin‐dependent stability control of a major RRB response activator.