Fig. 7.

Simplified scheme of the BR pathway at the early heading stage in WT (Left) or ic1 (Right) plants. In the presence of BR at the early heading stage, when BrOPS is highly expressed, BrOPS interacts directly with BrBIN2 at the plasma membrane, blocking BrBIN2 accumulation in the nucleus. Unphosphorylated BrBES1 accumulates in the nucleus, inhibiting transcription of BrAS1. Low expression of BrAS1 causes leaf outward curling in the WT. In the absence of BrOPS in ic1, BrBIN2 accumulates in the nucleus, phosphorylating the transcription factor BrBES1. Phosphorylated BrBES1 releases the repression of BrAS1 transcription, leading to leaf inward curling in ic1.