Attenuation of cytokinin signaling via proteolysis of a type-B response regulator.

Publisher: Taylor & Francis Country of Publication: United States NLM ID: 101291431 Publication Model: Print-Electronic Cited Medium: Internet ISSN: 1559-2324 (Electronic) Linking ISSN: 15592316 NLM ISO Abbreviation: Plant Signal Behav Subsets: MEDLINE

Publication: 2015- : Philadelphia, PA : Taylor & Francis
Original Publication: Georgetown, TX : Landes Bioscience

Proteolysis*/drug effects ; Signal Transduction*/drug effects; Arabidopsis/*metabolism ; Arabidopsis Proteins/*metabolism ; Cytokinins/*metabolism ; DNA-Binding Proteins/*metabolism ; Transcription Factors/*metabolism; Arabidopsis/drug effects ; Arabidopsis/genetics ; Arabidopsis Proteins/genetics ; Cytokinins/pharmacology ; DNA-Binding Proteins/genetics ; Gene Expression Regulation, Plant/drug effects ; Mutation/genetics ; Protein Binding/drug effects ; Transcription Factors/genetics

Type-B response regulators (ARRs) are a group of transcription factors that are activated by cytokinin-initiated phospho-relays and regulate the expression of cytokinin-responsive genes. Recently, we reported that proteolysis of ARR2 in Arabidopsis is facilitated by cytokinins, resulting in attenuation of the signaling output of two-component circuitry. Interestingly, despite similarities in the primary structures and conserved receiver domains, the proteolytic properties of ARR2 are distinct from those of the other type-B ARRs. Using a gain-of-function mutant (ARR2(K90G)) resistant to protein degradation, we clearly demonstrated that increased levels of ARR2 affected cytokinin-mediated processes such as primary root growth, callus induction, hypocotyl elongation and leaf senescence. At the molecular level, expression of type-A ARRs was increased in transgenics expressing ARR2(K90G), resulting in enhanced cytokinin sensitivity. Here, we describe these findings and how they may be incorporated into the currently accepted model for the regulation of cytokinin signaling. In addition, we describe the proteomic approaches used to identify proteins that interact with ARR2. The putative roles of ARR2 proteolysis are also addressed with regard to other developmental processes. In conclusion, cytokinin-facilitated degradation of ARR2 must be appreciated as a post-translational event important for regulating cytokinin signaling intensity.

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0 (ARR2 protein, Arabidopsis)
0 (Arabidopsis Proteins)
0 (Cytokinins)
0 (DNA-Binding Proteins)
0 (Transcription Factors)

Date Created: 20120704 Date Completed: 20130207 Latest Revision: 20211021

20221213

PMC3583957

10.4161/psb.20469

22751310