Pseudo-Response Regulators (PRRs) or True Oscillator Components (TOCs).
In Arabidopsis thaliana, AUTHENTIC RESPONSE REGULATORS (ARRs) act as downstream components of the His-to-Asp phosphorelay (two-component) signaling pathway that is propagated primarily by the cytokinin receptor kinases, AUTHENTIC HIS-KINASES (AHK2, AHK3 and AHK4/CRE1). Thus, this bacterial type of signaling system is essential for responses to a class of hormones in plants. Interestingly, this higher plant has also evolved its own atypical (or unique) variants of two-component signal transducers, PSEUDO-RESPONSE REGULATORS (PRRs). Several lines of recent results suggest that the functions of PRRs are closely relevant to the plant clock (oscillator) that is central to circadian rhythms, the underlying mechanisms of which have long been the subject of debate. Through an overview of recent results, the main issue addressed here is whether or not the pseudo-response regulators (PRRs) are true oscillator components (TOCs).
Mizuno
Takeshi
T
Laboratory of Molecular Microbiology, School of Agriculture, Nagoya University, Chikusa-ku, Nagoya, 464-8601 Japan. tmizuno@agr.nagoya-u.ac.jp
Nakamichi
Norihito
N
D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D001683:Biological Clocks / Q000235:genetics*; D002940:Circadian Rhythm / Q000235:genetics*; D018506:Gene Expression Regulation, Plant / Q000235:genetics; D015398:Signal Transduction / Q000502:physiology*; D014157:Transcription Factors; D015533:Transcriptional Activation / Q000502:physiology
D029681:Arabidopsis Proteins; C411822:TOC1 protein, Arabidopsis; D014157:Transcription Factors