BSKs Mediate Signal Transduction from the Receptor Kinase BRI1 in Arabidopsis

• Published in: Science (American Association for the Advancement of Science) Vol. 321; no. 5888; pp. 557 - 560
• Main Authors: Tang, Wenqiang, Kim, Tae-Wuk, Oses-Prieto, Juan A, Sun, Yu, Deng, Zhiping, Zhu, Shengwei, Wang, Ruiju, Burlingame, Alma L, Wang, Zhi-Yong
• Format: Journal Article
• Language: English
• Published: Washington, DC American Association for the Advancement of Science 25.07.2008; The American Association for the Advancement of Science
• Subjects: Agronomy. Soil science and plant productions; Amino Acid Sequence; Antibodies; Arabidopsis - enzymology; Arabidopsis - genetics; Arabidopsis - metabolism; Arabidopsis Proteins - chemistry; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Biochemistry; Biological and medical sciences; Botany; Brassinosteroids; Cell Membrane - metabolism; Cell membranes; Cholestanols - metabolism; Cholestanols - pharmacology; Fundamental and applied biological sciences. Psychology; Genetics and breeding of economic plants; Hypocotyls; Molecular Sequence Data; Mutagenesis, Insertional; Phenotypes; Phosphorylation; Plants, Genetically Modified; Protein Kinases - chemistry; Protein Kinases - genetics; Protein Kinases - metabolism; Protein Structure, Tertiary; Protein-Serine-Threonine Kinases; Proteins; Proteomics; Receptors; Recombinant Fusion Proteins - metabolism; Seedlings; Signal Transduction; Steroids; Steroids, Heterocyclic - metabolism; Steroids, Heterocyclic - pharmacology; Membrane protein; Enzyme; Transferases; Gene expression; Extracellular; Arabidopsis thaliana; Signal transduction; Brassinosteroid; Cruciferae; Kinase; Dicotyledones; Angiospermae; Plasma membrane; Proteomics; Genetics; Spermatophyta; Experimental plant
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1156973

Brassinosteroids (BRs) bind to the extracellular domain of the receptor kinase BRI1 to activate a signal transduction cascade that regulates nuclear gene expression and plant development. Many components of the BR signaling pathway have been identified and studied in detail. However, the substrate of BRI1 kinase that transduces the signal to downstream components remains unknown. Proteomic studies of plasma membrane proteins lead to the identification of three homologous BR-signaling kinases (BSK1, BSK2, and BSK3). The BSKs are phosphorylated by BRI1 in vitro and interact with BRI1 in vivo. Genetic and transgenic studies demonstrate that the BSKs represent a small family of kinases that activate BR signaling downstream of BRI1. These results demonstrate that BSKs are the substrates of BRI1 kinase that activate downstream BR signal transduction.