InterPro domain: IPR033264

Brassinosteroids (BRs) are essential steroid hormones that regulate plant growth and development [ 1 ]. This entry represents the BZR (BRASSINAZOLE-RESISTANT) family, whose members include BZR1 and BZR2 (BES1) from Arabidopsis [ 2 ]. BZR1 is a transcriptional repressor and a positive regulator of the brassinosteroid (BR) signalling pathway that mediates both downstream BR responses and negative feedback regulation of BR biosynthesis [ 3 ]. It interacts with REPRESSOR OF ga1-3 (RGA), a member of the DELLA family of transcriptional regulators that inhibits the GA signaling pathway in Arabidopsis thaliana [ 4 ]. BZR2/BES1 cooperates with MYB30 to regulate brassinosteroid-induced gene expression [ 5 ]. It also interacts with other transcription factors such as BIM1 and AtMYB30, as well as putative histone demethylases ELF6 and REF6 [ 6 , 7 , 7 ].

1. Molecular genetic studies confirm the role of brassinosteroids in plant growth and development. Plant J. 10, 1-8
2. Recent advances in the regulation of brassinosteroid signaling and biosynthesis pathways. J Integr Plant Biol 53, 455-68
3. BZR1 is a transcriptional repressor with dual roles in brassinosteroid homeostasis and growth responses. Science 307, 1634-8
4. An interaction between BZR1 and DELLAs mediates direct signaling crosstalk between brassinosteroids and gibberellins in Arabidopsis. Sci Signal 5, ra72
5. Arabidopsis MYB30 is a direct target of BES1 and cooperates with BES1 to regulate brassinosteroid-induced gene expression. Plant J. 58, 275-86
6. A new class of transcription factors mediates brassinosteroid-regulated gene expression in Arabidopsis. Cell 120, 249-59
7. Modulation of brassinosteroid-regulated gene expression by Jumonji domain-containing proteins ELF6 and REF6 in Arabidopsis. Proc. Natl. Acad. Sci. U.S.A. 105, 7618-23