Arabidopsis CULLIN4 forms an E3 ubiquitin ligase with RBX1 and the CDD complex in mediating light control of development

作者：Chen Haodong; Shen Yunping; Tang Xiaobo; Yu Lu; Wang Jia; Guo Lan; Zhang Yu; Zhang Huiyong; Feng Suhua; Strickland Elizabeth; Zheng Ning; Deng Xing Wang^*

来源：Plant Cell, 2006, 18(8): 1991-2004.

DOI：10.1105/tpc.106.043224

Repression of photomorphogenesis in Arabidopsis thaliana requires activity of the COP9 signalosome (CSN), CDD, and COP1 complexes, but how these three complexes work in concert to accomplish this important developmental switch has remained unknown. Here, we demonstrate that Arabidopsis CULLIN4 (CUL4) associates with the CDD complex and a common catalytic subunit to form an active E3 ubiquitin ligase both in vivo and in vitro. The partial loss of function of CUL4 resulted in a constitutive photomorphogenic phenotype with respect to morphogenesis and light-regulated gene expression. Furthermore, CUL4 exhibits a synergistic genetic interaction with COP10 and DET1. Therefore, this CUL4- based E3 ligase is essential for the repression of photomorphogenesis. This CUL4- based E3 ligase appears to associate physically with COP1 E3 ligase and positively regulates the COP1-dependent degradation of photomorphogenesis-promoting transcription factors, whereas the CSN controls the biochemical modification of CUL4 essential for E3 activity. Thus, this study suggests a biochemical activity connection between CSN and CDD complexes in their cooperation with COP1 in orchestrating the repression of photomorphogenesis.

• 出版日期2006-8
• 单位北京生命科学研究所; 北京大学