title: OsBRI1 Activates BR Signaling by Preventing Binding between the TPR and Kinase Domains of OsBSK3 via Phosphorylation.
abstract: Many plant receptor kinases transduce signals through receptor-like cytoplasmic kinases (RLCKs); however, the molecular mechanisms that create an effective on-off switch are unknown. The receptor kinase BR INSENSITIVE1 (BRI1) transduces brassinosteroid (BR) signal by phosphorylating members of the BR-signaling kinase (BSK) family of RLCKs, which contain a kinase domain and a C-terminal tetratricopeptide repeat (TPR) domain. Here, we show that the BR signaling function of BSKs is conserved in Arabidopsis (Arabidopsis thaliana) and rice (Oryza sativa) and that the TPR domain of BSKs functions as a "phospho-switchable" autoregulatory domain to control BSKs' activity. Genetic studies revealed that OsBSK3 is a positive regulator of BR signaling in rice, while in vivo and in vitro assays demonstrated that OsBRI1 interacts directly with and phosphorylates OsBSK3. The TPR domain of OsBSK3, which interacts directly with the protein's kinase domain, serves as an autoinhibitory domain to prevent OsBSK3 from interacting with bri1-SUPPRESSOR1 (BSU1). Phosphorylation of OsBSK3 by OsBRI1 disrupts the interaction between its TPR and kinase domains, thereby increasing the binding between OsBSK3's kinase domain and BSU1. Our results not only demonstrate that OsBSK3 plays a conserved role in regulating BR signaling in rice, but also provide insight into the molecular mechanism by which BSK family proteins are inhibited under basal conditions but switched on by the upstream receptor kinase BRI1.
authors.affiliation: Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Collaboration Innovation Center for Cell Signaling, Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang 050016, China (B.Z., X.W., Z.Z., R.W., Y.Z., L.Y., X.X., Y.G., Y.S., W.T.);Key Laboratory of Molecular Development Biology, Insitute of Genetics and Development Biology, Chinese Academy of Sciences, Beijing 100101, China (X.H., Y.W.); andMass spectrometry facility, Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94143 (A.L.B.).
authors.forename: Baowen
authors.identifier: http://orcid.org/0000-0002-4615-5273
authors.initials: B
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Collaboration Innovation Center for Cell Signaling, Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang 050016, China (B.Z., X.W., Z.Z., R.W., Y.Z., L.Y., X.X., Y.G., Y.S., W.T.);Key Laboratory of Molecular Development Biology, Insitute of Genetics and Development Biology, Chinese Academy of Sciences, Beijing 100101, China (X.H., Y.W.); andMass spectrometry facility, Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94143 (A.L.B.).
authors.forename: Xiaolong
authors.initials: X
authors.lastname: Wang
authors.affiliation: Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Collaboration Innovation Center for Cell Signaling, Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang 050016, China (B.Z., X.W., Z.Z., R.W., Y.Z., L.Y., X.X., Y.G., Y.S., W.T.);Key Laboratory of Molecular Development Biology, Insitute of Genetics and Development Biology, Chinese Academy of Sciences, Beijing 100101, China (X.H., Y.W.); andMass spectrometry facility, Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94143 (A.L.B.).
authors.forename: Zhiying
authors.initials: Z
authors.lastname: Zhao
authors.affiliation: Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Collaboration Innovation Center for Cell Signaling, Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang 050016, China (B.Z., X.W., Z.Z., R.W., Y.Z., L.Y., X.X., Y.G., Y.S., W.T.);Key Laboratory of Molecular Development Biology, Insitute of Genetics and Development Biology, Chinese Academy of Sciences, Beijing 100101, China (X.H., Y.W.); andMass spectrometry facility, Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94143 (A.L.B.).
authors.forename: Ruiju
authors.initials: R
authors.lastname: Wang
authors.affiliation: Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Collaboration Innovation Center for Cell Signaling, Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang 050016, China (B.Z., X.W., Z.Z., R.W., Y.Z., L.Y., X.X., Y.G., Y.S., W.T.);Key Laboratory of Molecular Development Biology, Insitute of Genetics and Development Biology, Chinese Academy of Sciences, Beijing 100101, China (X.H., Y.W.); andMass spectrometry facility, Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94143 (A.L.B.).
authors.forename: Xiahe
authors.initials: X
authors.lastname: Huang
authors.affiliation: Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Collaboration Innovation Center for Cell Signaling, Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang 050016, China (B.Z., X.W., Z.Z., R.W., Y.Z., L.Y., X.X., Y.G., Y.S., W.T.);Key Laboratory of Molecular Development Biology, Insitute of Genetics and Development Biology, Chinese Academy of Sciences, Beijing 100101, China (X.H., Y.W.); andMass spectrometry facility, Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94143 (A.L.B.).
authors.forename: Yali
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Collaboration Innovation Center for Cell Signaling, Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang 050016, China (B.Z., X.W., Z.Z., R.W., Y.Z., L.Y., X.X., Y.G., Y.S., W.T.);Key Laboratory of Molecular Development Biology, Insitute of Genetics and Development Biology, Chinese Academy of Sciences, Beijing 100101, China (X.H., Y.W.); andMass spectrometry facility, Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94143 (A.L.B.).
authors.forename: Li
authors.initials: L
authors.lastname: Yuan
authors.affiliation: Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Collaboration Innovation Center for Cell Signaling, Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang 050016, China (B.Z., X.W., Z.Z., R.W., Y.Z., L.Y., X.X., Y.G., Y.S., W.T.);Key Laboratory of Molecular Development Biology, Insitute of Genetics and Development Biology, Chinese Academy of Sciences, Beijing 100101, China (X.H., Y.W.); andMass spectrometry facility, Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94143 (A.L.B.).
authors.forename: Yingchun
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Collaboration Innovation Center for Cell Signaling, Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang 050016, China (B.Z., X.W., Z.Z., R.W., Y.Z., L.Y., X.X., Y.G., Y.S., W.T.);Key Laboratory of Molecular Development Biology, Insitute of Genetics and Development Biology, Chinese Academy of Sciences, Beijing 100101, China (X.H., Y.W.); andMass spectrometry facility, Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94143 (A.L.B.).
authors.forename: Xiaodong
authors.identifier: http://orcid.org/0000-0002-8795-7651
authors.initials: X
authors.lastname: Xu
authors.affiliation: Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Collaboration Innovation Center for Cell Signaling, Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang 050016, China (B.Z., X.W., Z.Z., R.W., Y.Z., L.Y., X.X., Y.G., Y.S., W.T.);Key Laboratory of Molecular Development Biology, Insitute of Genetics and Development Biology, Chinese Academy of Sciences, Beijing 100101, China (X.H., Y.W.); andMass spectrometry facility, Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94143 (A.L.B.).
authors.forename: Alma L
authors.initials: AL
authors.lastname: Burlingame
authors.affiliation: Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Collaboration Innovation Center for Cell Signaling, Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang 050016, China (B.Z., X.W., Z.Z., R.W., Y.Z., L.Y., X.X., Y.G., Y.S., W.T.);Key Laboratory of Molecular Development Biology, Insitute of Genetics and Development Biology, Chinese Academy of Sciences, Beijing 100101, China (X.H., Y.W.); andMass spectrometry facility, Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94143 (A.L.B.).
authors.forename: Yingjie
authors.initials: Y
authors.lastname: Gao
authors.affiliation: Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Collaboration Innovation Center for Cell Signaling, Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang 050016, China (B.Z., X.W., Z.Z., R.W., Y.Z., L.Y., X.X., Y.G., Y.S., W.T.);Key Laboratory of Molecular Development Biology, Insitute of Genetics and Development Biology, Chinese Academy of Sciences, Beijing 100101, China (X.H., Y.W.); andMass spectrometry facility, Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94143 (A.L.B.).
authors.forename: Yu
authors.identifier: http://orcid.org/0000-0002-1931-8583
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Collaboration Innovation Center for Cell Signaling, Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang 050016, China (B.Z., X.W., Z.Z., R.W., Y.Z., L.Y., X.X., Y.G., Y.S., W.T.);Key Laboratory of Molecular Development Biology, Insitute of Genetics and Development Biology, Chinese Academy of Sciences, Beijing 100101, China (X.H., Y.W.); andMass spectrometry facility, Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94143 (A.L.B.) tangwq@mail.hebtu.edu.cn.
authors.forename: Wenqiang
authors.identifier: http://orcid.org/0000-0002-2972-5748
authors.initials: W
authors.lastname: Tang
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics; D060406:Brassinosteroids / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D012275:Oryza / Q000201:enzymology / Q000378:metabolism*; D010641:Phenotype; D010748:Phosphopeptides / Q000737:chemistry / Q000378:metabolism; D010766:Phosphorylation; D010768:Phosphoserine / Q000378:metabolism; D010940:Plant Proteins / Q000737:chemistry* / Q000378:metabolism*; D030821:Plants, Genetically Modified; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D015398:Signal Transduction; D013379:Substrate Specificity
chemical_list: D060406:Brassinosteroids; D010748:Phosphopeptides; D010940:Plant Proteins; D010768:Phosphoserine