BSKs mediate signal transduction from the receptor kinase BRI1 in Arabidopsis.
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.
Tang
Wenqiang
W
Department of Plant Biology, Carnegie Institution of Washington, Stanford, CA 94305, USA.
Kim
Tae-Wuk
TW
Oses-Prieto
Juan A
JA
Sun
Yu
Y
Deng
Zhiping
Z
Zhu
Shengwei
S
Wang
Ruiju
R
Burlingame
Alma L
AL
Wang
Zhi-Yong
ZY
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D060406:Brassinosteroids; D002462:Cell Membrane / Q000378:metabolism; D002777:Cholestanols / Q000378:metabolism / Q000494:pharmacology; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D010766:Phosphorylation; D030821:Plants, Genetically Modified; D011494:Protein Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases; D017434:Protein Structure, Tertiary; D040901:Proteomics; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D015398:Signal Transduction; D013260:Steroids, Heterocyclic / Q000378:metabolism / Q000494:pharmacology
D029681:Arabidopsis Proteins; D060406:Brassinosteroids; D002777:Cholestanols; D011993:Recombinant Fusion Proteins; D013260:Steroids, Heterocyclic; D011494:Protein Kinases; C108270:BRI1 protein, Arabidopsis; D017346:Protein Serine-Threonine Kinases; C530518:brassinosteroid-signaling kinase1, Arabidopsis; C530531:brassinosteroid-signaling kinase2, Arabidopsis; C530532:brassinosteroid-signaling kinase3, Arabidopsis; C023623:brassinolide