The RING-Finger E3 Ubiquitin Ligase COP1 SUPPRESSOR1 Negatively Regulates COP1 Abundance in Maintaining COP1 Homeostasis in Dark-Grown Arabidopsis Seedlings
Journal article, 2014
CONSTITUTIVE PHOTOMORPHOGENIC1 (COP1) functions as an E3 ubiquitin ligase in both plants and animals. In dark-grown Arabidopsis thaliana seedlings, COP1 targets photomorphogenesis-promoting factors for degradation to repress photomorphogenesis. Little is known, however, about how COP1 itself is regulated. Here, we identify COP1 SUPPRESSOR1 (CSU1), a RING-finger E3 ubiquitin ligase, as a regulator of COP1. Genetic evidence demonstrates that csu1 mutations suppress cop1-6 phenotypes completely in the dark. Furthermore, CSU1 colocalizes with COP1 in nuclear speckles and negatively regulates COP1 protein accumulation in darkness. CSU1 can ubiquitinate COP1 in vitro and is essential for COP1 ubiquitination in vivo. Therefore, we conclude that CSU1 plays a major role in maintaining COP1 homeostasis by targeting COP1 for ubiquitination and degradation in dark-grown seedlings.
GENE-EXPRESSION
LIGHT-DEPENDENT INTERACTION
Biochemistry & Molecular Biology
Cell Biology
CRYPTOCHROME
Plant Sciences
CONSTITUTIVELY
BLUE-LIGHT
B-BOX
PHOTOMORPHOGENIC1
1
TUMOR-SUPPRESSOR
UV-B
MEDIATED DEVELOPMENT
PROTEIN
PHOTOMORPHOGENIC REPRESSOR COP1
Author
Dongqing Xu
University of Gothenburg
Fang Lin
Jiang Yang
University of Gothenburg
Xi Huang
Jigang Li
Junjie Ling
Chamari Hettiarachchi
University of Gothenburg
Christian Tellgren-Roth
Magnus Holm
University of Gothenburg
Xing Wang Deng
Plant Cell
1040-4651 (ISSN) 1532-298X (eISSN)
Vol. 26 5 1981-1991Subject Categories
Biological Sciences
DOI
10.1105/tpc.114.124024