Jijie Chai Research Group from Tsinghua Published Article in Nature, Revealing New Receptor Activation Mechanism by Plant Peptide Hormone
The research group led by Prof. Jijie Chai from School of Life Sciences, Tsinghua University, collaborated with Dr. Weicai Yang’s group from the Institute of Genetics and Developmental Biology, Chinese Academy of Sciences published a paper in Nature online on August 26, 2015. The paper entitled "Allosteric receptor activation by the plant peptide hormone phytosulfokine” reported the crystal structures of phytosulfokine (PSK) recognition complex and receptor activation complex, revealing the new receptor activation mechanism by PSK.
Plant peptide hormone plays critical roles in regulating plant physiology. PSK is a secreted disulfated pentapeptide (Tyr(SO3H)-Ile-Tyr(SO3H)-Thr-Gln) which has ubiquitous roles in plant growth and development. PSK is perceived by its receptor PSKR, a leucine-rich repeat receptor kinase (LRR-RK). The mechanisms underlying the recognition, PSKR activation and components downstream of the initial perception remain elusive.
Prof. Jijie Chai’s Research Group solved the crystal structure of PSKR ectodomains complexed with PSK. The structure reveals the recognition mechanism that PSK mainly interacts with the island domain of PSKR. Based on the structural analysis, the research group hypothesized that SERK members may act as co-receptors involved in PSKR activation. Through collaboration with researchers from Dr. Weicai Yang’s group, the hypothesis was verified by in vitro and in vivo experiments. It’s a successful case that structure biology guides the discovery of new components in PSK signal transduction pathway. With many trials, Prof. Jijie Chai’s Research Group further determined the PSKR-PSK-SERK activation complex structure and firstly reveals a new receptor activation mechanism that PSK induces the conformational changes of PSKR and allosterically induces the interface for PSKR-SERKs interaction.
Fig. crystal structures of PSK recognition and activation complexes.
(A) Overall structure of PSK-PSKR. (B) PSKR-SERKs interaction in planta. (C) Overall structure of PSK-PSKR-SERK. (D) Structural comparison of the ligand-bound PSKR with the free PSKR.
PSKR-PSK-SERK activation complex is the first plant peptide hormone activation complex structure. The activation model further supports the dimerization model and probably reveals the attractive scenario that SERKs can be co-receptors of multiple peptide hormone-receptor pairs. From the structural view, the activation mechanism differs to the “molecular glue” activation mechanism of the classific plant hormones such as auxin, jasmonic acid and brassinolide, and flg22 induced FLS2-BAK1 interaction. Based on these structures, the analogues of PSK, which are suitable for plant growth additives, can be designed for crops yield promotion.
Prof. Jijie Chai from School of Life Sciences, Tsinghua University, and Dr. Weicai Yang from Institute of Genetics and Developmental Biology are the corresponding authors of the paper; Jizong Wang (PhD student) from School of Life Sciences, Tsinghua University, and Hongju Li (associate research fellow) from CAS Institute of Genetics and Developmental Biology are co-first authors; Dr. Zhifu Han and Heqiao Zhang (PhD student) from School of Life Sciences, Tsinghua University and Prof. Junbiao Chang from School of Chemistry and Molecular Engineering, Zhengzhou University also participated in part of the work. Shanghai Synchrotron Radiation (SSRF, Beam line BL17U1) provided support for diffraction data collection. This research in Tsinghua University was funded by Projects of International Cooperation and Exchanges NSFC (31420103906), Chinese Ministry of Science and Technology (2015CB910200) and State Key Program of National Natural Science of China (31130063).
The paper links：http://www.nature.com/nature/journal/vaop/ncurrent/full/nature14858.html
(From School of Life Sciences)
