Transcriptional repressor that binds to the brassinosteroid (BR) response element (BRRE) 5'-CGTG(T/C)G-3' in gene promoter. Regulates positively the brassinosteroid-signaling pathway (PubMed:33324437). Mediates downstream growth responses and negative feedback regulation of brassinosteroid biosynthesis. Promotes growth. Modulates ovule initiation and development by monitoring the expression of genes related to ovule development (e.g. HLL, ANT, and AP2). Regulates negatively the abscisic acid (ABA) signaling pathway during the post-germination stage (PubMed:33324437). Homodimer (PubMed:30287951). Interacts with BIN2 through its C-terminal fragment (PubMed:12427989, PubMed:12114546). Interacts with MKK5 (PubMed:24019147). Interacts with SAUR50 (PubMed:23020777). Interacts with B'ALPHA, B'BETA, B'ETA and B'THETA (PubMed:21258370). Accumulates in the growing region of the hypocotyl. By brassinosteroid (BR) (PubMed:15681342). Up-regulated in response to abscisic acid (ABA) via epigenetic regulation on repressive histone marks (H3K27me3) mediated by JMJ30 and JMJ32 (PubMed:33324437). Phosphorylated by BIN2 and MKK5 in response to brassinosteroid (BR). Dephosphorylation level is consistent with ovule and seed number. In bzr1-1D, weak dwarf phenotype with reduced hypocotyl and petiole lengths and dark green curled leaves when light-grown. Increased cell elongation in the dark. Hypersensitive to brassinosteroid (BR). Phosphorylation by BIN2 increases protein degradation and/or interferes with the nuclear localization. Belongs to the BZR/LAT61 family.