PMID- 21093457
OWN - NLM
STAT- MEDLINE
DCOM- 20110527
LR  - 20211020
IS  - 1095-8541 (Electronic)
IS  - 0022-5193 (Print)
IS  - 0022-5193 (Linking)
VI  - 270
IP  - 1
DP  - 2011 Feb 7
TI  - Ubiquitin ligase switch in plant photomorphogenesis: A hypothesis.
PG  - 31-41
LID - 10.1016/j.jtbi.2010.11.021 [doi]
AB  - The E3 ubiquitin ligase COP1 (CONSTITUTIVE PHOTOMORPHOGENIC1) plays a key role in 
      the repression of the plant photomorphogenic development in darkness. In the 
      presence of light, COP1 is inactivated by a mechanism which is not completely 
      understood. This leads to accumulation of COP1's target transcription factors, 
      which initiates photomorphogenesis, resulting in dramatic changes of the 
      seedling's physiology. Here we use a mathematical model to explore the possible 
      mechanism of COP1 modulation upon dark/light transition in Arabidopsis thaliana 
      based upon data for two COP1 target proteins: HY5 and HFR1, which play critical 
      roles in photomorphogenesis. The main reactions in our model are the inactivation 
      of COP1 by a proposed photoreceptor-related inhibitor I and interactions between 
      COP1 and a CUL4 (CULLIN4)-based ligase. For building and verification of the 
      model, we used the available published and our new data on the kinetics of HY5 
      and HFR1 together with the data on COP1 abundance. HY5 has been shown to 
      accumulate at a slower rate than HFR1. To describe the observed differences in 
      the timecourses of the "slow" target HY5 and the "fast" target HFR1, we 
      hypothesize a switch between the activities of COP1 and CUL4 ligases upon 
      dark/light transition, with COP1 being active mostly in darkness and CUL4 in 
      light. The model predicts a bi-phasic kinetics of COP1 activity upon the exposure 
      of plants to light, with its restoration after the initial decline and the 
      following slow depletion of the total COP1 content. CUL4 activity is predicted to 
      increase in the presence of light. We propose that the ubiquitin ligase switch is 
      important for the complex regulation of multiple transcription factors during 
      plants development. In addition, this provides a new mechanism for sensing the 
      duration of light period, which is important for seasonal changes in plant 
      development.
CI  - Copyright A(c) 2010 Elsevier Ltd. All rights reserved.
FAU - Pokhilko, Alexandra
AU  - Pokhilko A
AD  - School of Biological Sciences, University of Edinburgh, Mayfield Road, Edinburgh 
      EH9 3JH, United Kingdom. apokhilk@staffmail.ed.ac.uk
FAU - Ramos, Jason A
AU  - Ramos JA
FAU - Holtan, Hans
AU  - Holtan H
FAU - Maszle, Don R
AU  - Maszle DR
FAU - Khanna, Rajnish
AU  - Khanna R
FAU - Millar, Andrew J
AU  - Millar AJ
LA  - eng
GR  - BB/E015263/1/BB_/Biotechnology and Biological Sciences Research Council/United 
      Kingdom
PT  - Journal Article
DEP - 20101118
PL  - England
TA  - J Theor Biol
JT  - Journal of theoretical biology
JID - 0376342
RN  - 0 (Arabidopsis Proteins)
RN  - 0 (Basic-Leucine Zipper Transcription Factors)
RN  - 0 (CULLIN4 protein, Arabidopsis)
RN  - 0 (Cullin Proteins)
RN  - 0 (DNA-Binding Proteins)
RN  - 0 (HFR1 protein, Arabidopsis)
RN  - 0 (HY5 protein, Arabidopsis)
RN  - 0 (Nuclear Proteins)
RN  - EC 2.3.2.27 (AT2G32950 protein, Arabidopsis)
RN  - EC 2.3.2.27 (Ubiquitin-Protein Ligases)
SB  - IM
MH  - Algorithms
MH  - Arabidopsis/*growth & development/metabolism/*radiation effects
MH  - Arabidopsis Proteins/antagonists & inhibitors/genetics/*metabolism
MH  - Basic-Leucine Zipper Transcription Factors/genetics/metabolism
MH  - Computer Simulation
MH  - Cullin Proteins/metabolism
MH  - DNA-Binding Proteins/genetics/metabolism
MH  - Down-Regulation/radiation effects
MH  - Gene Expression Regulation, Plant/physiology/radiation effects
MH  - Kinetics
MH  - *Models, Biological
MH  - Morphogenesis/physiology/*radiation effects
MH  - Nuclear Proteins/genetics/metabolism
MH  - *Photoperiod
MH  - Ubiquitin-Protein Ligases/antagonists & inhibitors/*metabolism
MH  - Up-Regulation/radiation effects
PMC - PMC3021735
EDAT- 2010/11/26 06:00
MHDA- 2011/05/28 06:00
PMCR- 2011/02/07
CRDT- 2010/11/25 06:00
PHST- 2010/03/06 00:00 [received]
PHST- 2010/11/09 00:00 [revised]
PHST- 2010/11/11 00:00 [accepted]
PHST- 2010/11/25 06:00 [entrez]
PHST- 2010/11/26 06:00 [pubmed]
PHST- 2011/05/28 06:00 [medline]
PHST- 2011/02/07 00:00 [pmc-release]
AID - S0022-5193(10)00606-5 [pii]
AID - 10.1016/j.jtbi.2010.11.021 [doi]
PST - ppublish
SO  - J Theor Biol. 2011 Feb 7;270(1):31-41. doi: 10.1016/j.jtbi.2010.11.021. Epub 2010 
      Nov 18.