期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2013
卷号：110
期号：41
页码：16669-16674
DOI：10.1073/pnas.1316622110
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：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.
关键词：light signaling ; protein complex ; posttranscriptional regulation
