In rice DWARF14 (D14) and DWARF3 (D3) proteins play crucial roles in strigolactone (SL) signal transduction. D14, an ?/? hydrolase, is responsible for SL perception, while D3, an F-box protein with leucine-rich repeats, is essential for SL signal transduction. In the nucleus, D14 associates with D3 and D53 in a strigolactone-dependent manner, which leads to the D53 ubiquitination and degradation. D53 acts as a repressor of SL signaling. The rice hyper-branching mutant d53 (containing a 5-amino-acid deletion and a single amino acid substitution) shows a defect in D53 ubiquitination. As a result, the mutant-type D53 protein constitutively repressed SL signaling (Jiang et al., 2013; Zhou et al., 2013).
