Conformational Dynamics of the D53−D3−D14 Complex in Strigolactone Signaling

作者：Simiao Liu, Jia Wang, Bin Song, Xinqi Gong, Huihui Liu, Qingliang Hu, Junhui Zhang, Qianqian Li, Jie Zheng, Hong‐Wei Wang, H. Eric Xu, Jiayang Li, Bing Wang · 发表于：Plant and Cell Physiology · 年份：2023 · DOI：10.1093/pcp/pcad067 · 被引用次数：17 · 研究领域：Plant Parasitism and Resistance、Plant and animal studies、Plant Molecular Biology Research

Strigolactones (SLs) play fundamental roles in regulating plant architecture, which is a major factor determining crop yield. The perception and signal transduction of SLs require the formation of a complex containing the receptor DWARF14 (D14), an F-box protein D3 and a transcriptional regulator D53 in an SL-dependent manner. Structural and biochemical analyses of D14 and its orthologs DAD2 and AtD14, D3 and the complexes of ASK1-D3-AtD14 and D3CTH-D14 have made great contributions to understanding the mechanisms of SL perception. However, structural analyses of D53 and the D53-D3-D14 holo-complex are challenging, and the biochemical mechanism underlying the complex assembly remains poorly understood. Here, we found that apo-D53 was rather flexible and reconstituted the holo-complex containing D53, S-phase kinase-associated protein 1 (SKP1), D3 and D14 with rac-GR24. The cryo-electron microscopy (cryo-EM) structure of SKP1-D3-D14 in the presence of D53 was analyzed and superimposed on the crystal structure of ASK1-D3-AtD14 without D53. No large conformational rearrangement was observed, but a 9Å rotation appeared between D14 and AtD14. Using hydrogen-deuterium exchange monitored by mass spectrometry, we analyzed dynamic motifs of D14, D3 and D53 in the D53-SKP1-D3-D14 complex assembly process and further identified two potential interfaces in D53 that are located in the N and D2 domains, respectively. Together, our results uncovered the dynamic conformational changes and bui...