title: Allosteric receptor activation by the plant peptide hormone phytosulfokine.
abstract: Phytosulfokine (PSK) is a disulfated pentapeptide that has a ubiquitous role 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 of PSK, the activation of PSKR and the identity of the components downstream of the initial binding remain elusive. Here we report the crystal structures of the extracellular LRR domain of PSKR in free, PSK- and co-receptor-bound forms. The structures reveal that PSK interacts mainly with a β-strand from the island domain of PSKR, forming an anti-β-sheet. The two sulfate moieties of PSK interact directly with PSKR, sensitizing PSKR recognition of PSK. Supported by biochemical, structural and genetic evidence, PSK binding enhances PSKR heterodimerization with the somatic embryogenesis receptor-like kinases (SERKs). However, PSK is not directly involved in PSKR-SERK interaction but stabilizes PSKR island domain for recruitment of a SERK. Our data reveal the structural basis for PSKR recognition of PSK and allosteric activation of PSKR by PSK, opening up new avenues for the design of PSKR-specific small molecules.
authors: Ministry of Education Key Laboratory of Protein Science, Center for Structural Biology, School of Life Sciences, Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing 100084, China.
authors: Jizong
authors: J
authors: Wang
authors: State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.
authors: Hongju
authors: H
authors: Li
authors: Ministry of Education Key Laboratory of Protein Science, Center for Structural Biology, School of Life Sciences, Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing 100084, China.
authors: Zhifu
authors: Z
authors: Han
authors: Ministry of Education Key Laboratory of Protein Science, Center for Structural Biology, School of Life Sciences, Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing 100084, China.
authors: Heqiao
authors: H
authors: Zhang
authors: State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.
authors: Tong
authors: T
authors: Wang
authors: Ministry of Education Key Laboratory of Protein Science, Center for Structural Biology, School of Life Sciences, Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing 100084, China.
authors: Guangzhong
authors: G
authors: Lin
authors: School of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450001, China.
authors: Junbiao
authors: J
authors: Chang
authors: State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.
authors: Weicai
authors: W
authors: Yang
authors: Ministry of Education Key Laboratory of Protein Science, Center for Structural Biology, School of Life Sciences, Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing 100084, China.
authors: Jijie
authors: J
authors: Chai
mesh_terms: D000494:Allosteric Regulation / Q000187:drug effects; D017360:Arabidopsis / Q000737:chemistry*; D029681:Arabidopsis Proteins / Q000819:agonists* / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D009154:Mutation / Q000235:genetics; D036361:Peptide Hormones / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D010937:Plant Growth Regulators / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology*; D010940:Plant Proteins / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D011485:Protein Binding; D011494:Protein Kinases / Q000737:chemistry / Q000378:metabolism; D055503:Protein Multimerization / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry / Q000378:metabolism; D055550:Protein Stability; D017433:Protein Structure, Secondary / Q000187:drug effects; D017434:Protein Structure, Tertiary / Q000187:drug effects; D011956:Receptors, Cell Surface / Q000819:agonists* / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D029681:Arabidopsis Proteins; C100975:PSK-alpha protein, plant; C515018:PSKR1 protein, Arabidopsis; D036361:Peptide Hormones; D010937:Plant Growth Regulators; D010940:Plant Proteins; D011956:Receptors, Cell Surface; D011494:Protein Kinases; C440035:SERK1 protein, Arabidopsis; D017346:Protein Serine-Threonine Kinases; C000601951:somatic embryogenesis receptor-like kinase 2, Arabidopsis