Structural insight into UV-B-activated UVR8 bound to COP1

Yidong Wang; Lixia Wang; Zeyuan Guan; Hongfei Chang; Ling Ma; Cuicui Shen; Liang Qiu; Junjie Yan; Delin Zhang; Jian Li; Xing Wang Deng; Ping Yin

doi:10.1126/sciadv.abn3337

Structural insight into UV-B-activated UVR8 bound to COP1

Sci Adv. 2022 Apr 22;8(16):eabn3337. doi: 10.1126/sciadv.abn3337. Epub 2022 Apr 20.

Authors

Yidong Wang¹, Lixia Wang¹, Zeyuan Guan¹, Hongfei Chang¹, Ling Ma¹, Cuicui Shen¹, Liang Qiu¹, Junjie Yan¹, Delin Zhang¹, Jian Li², Xing Wang Deng^{2

3}, Ping Yin¹

Affiliations

¹ National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan 430070, China.
² Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes, Institute of Plant and Food Science, School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China.
³ School of Advanced Agricultural Sciences and School of Life Sciences, State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China.

Abstract

The CONSTITUTIVE PHOTOMORPHOGENIC 1-SUPPRESSOR OF PHYA-105 (COP1-SPA) complex is a central repressor of photomorphogenesis. This complex acts as an E3 ubiquitin ligase downstream of various light signaling transduced from multiple photoreceptors in plants. How the COP1-SPA activity is regulated by divergent light-signaling pathways remains largely elusive. Here, we reproduced the regulation pathway of COP1-SPA in ultraviolet-B (UV-B) signaling in vitro and determined the cryo-electron microscopy structure of UV-B receptor UVR8 in complex with COP1. The complex formation is mediated by two-interface interactions between UV-B-activated UVR8 and COP1. Both interfaces are essential for the competitive binding of UVR8 against the signaling hub component HY5 to the COP1-SPA complex. We also show that RUP2 dissociates UVR8 from the COP1-SPA4^1-464-UVR8 complex and facilitates its redimerization. Our results support a UV-B signaling model that the COP1-SPA activity is repressed by UV-B-activated UVR8 and derepressed by RUP2, owing to competitive binding, and provide a framework for studying the regulatory roles of distinct photoreceptors on photomorphogenesis.