Conversion from CUL4-based COP1-SPA E3 apparatus to UVR8-COP1-SPA complexes underlies a distinct biochemical function of COP1 under UV-B.
The evolutionarily conserved constitutive photomorphogenesis 1 (COP1) is a RING and WD40 protein that functions as a substrate receptor of CULLIN4-damaged DNA binding protein 1 (CUL4-DDB1)-based E3 ubiquitin ligases in both plants and animals. In Arabidopsis, COP1 is a central repressor of photomorphogenesis in the form of COP1-suppressor of PHYA (SPA) complex(es). CUL4-DDB1-COP1-SPA suppresses the photomorphogenic program by targeting the transcription factor elongated hypocotyl 5 for degradation. Intriguingly, under photomorphogenic UV-B light, COP1 reverses its repressive role and promotes photomorphogenesis. However, the mechanism by which COP1 is functionally switched is still obscure. Here, we demonstrate that UV-B triggers the physical and functional disassociation of the COP1-SPA core complex(es) from CUL4-DDB1 and the formation of a unique complex(es) containing the UV-B receptor UV resistance locus 8 (UVR8). The establishment of this UV-B-dependent COP1 complex(es) is associated with its positive modulation of elongated hypocotyl 5 stability and activity, which sheds light on the mechanism of COP1's promotive action in UV-B-induced photomorphogenesis.
Peking-Yale Joint Center for Plant Molecular Genetics and Agro-Biotechnology, National Laboratory of Protein Engineering and Plant Genetic Engineering, College of Life Sciences, Peking University, Beijing 100871, China.
Xi
X
Huang
Xinhao
X
Ouyang
Panyu
P
Yang
On Sun
OS
Lau
Liangbi
L
Chen
Ning
N
Wei
Xing Wang
XW
Deng
D017360:Arabidopsis; D029681:Arabidopsis Proteins / Q000378:metabolism* / Q000502:physiology* / Q000528:radiation effects; D050976:Basic-Leucine Zipper Transcription Factors / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000378:metabolism*; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism*; D044842:Cullin Proteins / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D015151:Immunoblotting; D047468:Immunoprecipitation; D055537:Light Signal Transduction / Q000502:physiology*; D046912:Multiprotein Complexes / Q000378:metabolism* / Q000528:radiation effects; D009687:Nuclear Proteins / Q000378:metabolism; D063245:Plant Development / Q000502:physiology* / Q000528:radiation effects; D060888:Real-Time Polymerase Chain Reaction; D020798:Two-Hybrid System Techniques; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism; D014466:Ultraviolet Rays
D029681:Arabidopsis Proteins; D050976:Basic-Leucine Zipper Transcription Factors; C514806:CULLIN4 protein, Arabidopsis; D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D044842:Cullin Proteins; C517426:DDB1a protein, Arabidopsis; D004268:DNA-Binding Proteins; C109254:HY5 protein, Arabidopsis; D046912:Multiprotein Complexes; D009687:Nuclear Proteins; C118571:SPA1 protein, Arabidopsis; C525052:Uvr8 protein, Arabidopsis; C471983:AT2G32950 protein, Arabidopsis; D044767:Ubiquitin-Protein Ligases
light signaling; posttranscriptional regulation; protein complex