RUP2 facilitates UVR8 redimerization via two interfaces  

作　　者：Lixia Wang Yidong Wang Hongfei Chang Hui Ren Xinquan Wu Jia Wen Zeyuan Guan Ling Ma Liang Qiu Junjie Yan Delin Zhang Xi Huang Ping Yin 

机构地区：[1]National Key Laboratory of Crop Genetic Improvement,Hubei Hongshan Laboratory,Huazhong Agricultural University,Wuhan 430070,China [2]State Key Laboratory of Cellular Stress Biology,School of Life Sciences,Faculty of Medicine and Life Sciences,Xiamen University,Xiamen 361102,China

出　　处：《Plant Communications》2023年第1期136-147,共12页植物通讯（英文）

基　　金：supported by funds from the National Key R&D Program of China(2018YFA0507700 and 2017YFA0506100);the National Natural Science Foundation of China(31722017,31870753,and 32122011);the Foundation of Hubei Hongshan Laboratory(2021hszd010);the China Postdoctoral Science Foundation(2020M682437 for Ling Ma).

摘　　要：The plant UV-B photoreceptor UV RESISTANCE LOCUS 8(UVR8)exists as a homodimer in its inactive ground state.Upon UV-B exposure,UVR8monomerizes and interacts with a downstreamkey regulator,theCONSTITUTIVE PHOTOMORPHOGENIC 1/SUPPRESSOR OF PHYA(COP1/SPA)E3 ubiquitin ligase complex,to initiate UV-B signaling.Two WD40 proteins,REPRESSOR OF UV-B PHOTOMORPHOGENESIS 1(RUP1)and RUP2 directly interact with monomeric UVR8 and facilitate UVR8 ground state reversion,completing the UVR8 photocycle.Here,we reconstituted the RUP-mediated UVR8 redimerization process in vitro and reported the structure of the RUP2-UVR8^(W285A) complex(2.0A).RUP2 and UVR8^(W285A) formed a heterodimer via two distinct interfaces,designated Interface 1 and 2.The previously characterized Interface 1 is found between the RUP2 WD40 domain and the UVR8 C27 subregion.The newly identified Interface 2 is formed through interactions between the RUP2 WD40 domain and the UVR8 core domain.Disruption of Interface 2 impairedUV-B induced photomorphogenic development in Arabidopsis thaliana.Further biochemical analysis indicated that both interfaces are important for RUP2-UVR8 interactions and RUP2-mediated facilitation of UVR8 redimerization.Our findings suggest that the two-interface-interaction mode is adopted by both RUP2 and COP1 when they interact with UVR8,marking a step forward in understanding the molecular basis that underpins the interactions between UVR8 and its photocycle regulators.

关 键 词：PHOTOMORPHOGENESIS UV-B photoreceptor UVR8 RUP2 COP1 

分 类 号：Q945[生物学—植物学]