Brassinosteroid signal transduction from receptor kinases to transcription factors.
Brassinosteroids (BRs) are growth-promoting steroid hormones in plants. Genetic studies in Arabidopsis illustrated the essential roles of BRs in a wide range of developmental processes and helped identify many genes involved in BR biosynthesis and signal transduction. Recently, proteomic studies identified missing links. Together, these approaches established the BR signal transduction cascade, which includes BR perception by the BRI1 receptor kinase at the cell surface, activation of BRI1/BAK1 kinase complex by transphosphorylation, subsequent phosphorylation of the BSK kinases, activation of the BSU1 phosphatase, dephosphorylation and inactivation of the BIN2 kinase, and accumulation of unphosphorylated BZR transcription factors in the nucleus. Mass spectrometric analyses are providing detailed information on the phosphorylation events involved in each step of signal relay. Thus, the BR signaling pathway provides a paradigm for understanding receptor kinase-mediated signal transduction as well as tools for the genetic improvement of the productivity of crop plants.
Kim
Tae-Wuk
TW
Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305, USA.
Wang
Zhi-Yong
ZY
D017360:Arabidopsis / Q000378:metabolism; D010766:Phosphorylation; D010940:Plant Proteins / Q000378:metabolism*; D010944:Plants / Q000378:metabolism*; D011494:Protein Kinases / Q000378:metabolism; D015398:Signal Transduction; D014157:Transcription Factors / Q000378:metabolism*
D010940:Plant Proteins; D014157:Transcription Factors; D011494:Protein Kinases