Two-component circuitry in Arabidopsis cytokinin signal transduction

@article{Hwang2001TwocomponentCI,
  title={Two-component circuitry in Arabidopsis cytokinin signal transduction},
  author={Ildoo Hwang and Jen Sheen},
  journal={Nature},
  year={2001},
  volume={413},
  pages={383-389}
}
Cytokinins are essential plant hormones that are involved in shoot meristem and leaf formation, cell division, chloroplast biogenesis and senescence. Although hybrid histidine protein kinases have been implicated in cytokinin perception in Arabidopsis, the action of histidine protein kinase receptors and the downstream signalling pathway has not been elucidated to date. Here we identify a eukaryotic two-component signalling circuit that initiates cytokinin signalling through distinct hybrid… 
Arabidopsis Cytokinin Signaling Pathway
TLDR
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The evolutionarily ancient two-component system that is used by cytokinin branches to incorporate a unique family of plant-specific transcription factors is revealed.
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TLDR
Global expression profiling revealed a complex ARR2‐involving two‐component network that interferes with a multitude of different signalling pathways and thereby contributes to the highly integrated signal processing machinery in higher plants.
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TLDR
Members of the Response Regulator protein family in Arabidopsis thaliana contain the conserved N-terminal receiver domain required for phosphorylation by two-component elements and can be classified into three groups based on sequence similarity and protein structure: type-A, type-B and type-C ARRs.
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TLDR
It is proposed that ARR22, by acting as a phosphatase on specific AHPs, disrupts the TCS phosphorelay and prevents B-type ARR phosphorylation, and thus their activation as transcription factors, explaining the observed deactivation of cytokinin-responsive genes.
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TLDR
Cytokinins enhance resistance against pathogens via a direct induction of defense-related genes, in cooperation with SA, by modulating the NPR1/TGA3-mediated signaling.
Cytokinin-facilitated proteolysis of ARABIDOPSIS RESPONSE REGULATOR 2 attenuates signaling output in two-component circuitry.
TLDR
It is demonstrated that the proteolysis of ARR2, a type-B ARR, modulates cytokinin signaling outputs and is involved in the maintenance of the primary signaling output for normal developmental processes mediated by cytokinIn in Arabidopsis.
Cytokinin Regulation of Plant Growth and Stress Responses
TLDR
Full utilization of cytokinin potential to improve plant productivity by regulation of plant development has been limited by the necessity of targeting modulation of their levels or signal transduction in a time- and tissue-specific manner.
Cytokinin Regulates Type-A Arabidopsis Response Regulator Activity and Protein Stability via Two-Component Phosphorelay[W]
TLDR
The results indicate that phosphorylation of the receiver domain is required for type-A ARR function and suggest that negative regulation of cytokinin signaling by the type-B ARRs most likely involves phosphorylated-dependent interactions, and show that a subset of the type of ARR proteins are stabilized in response to cytokinIn in part via phosphorylations.
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