Component of light signal transduction machinery. Involved in fruit pigmentation and fruit nutritional quality. Acts as a negative regulator of fruit pigmentation. Probably acts by participating in the CDD complex, a complex probably required to regulate the activity of ubiquitin conjugating enzymes. Repression of photomorphogenesis is probably mediated by ubiquitination and subsequent degradation of photomorphogenesis-promoting factors such as HY5 (By similarity). Protein modification; protein ubiquitination. Probable component of the CDD complex, which probably also contains DET1. Belongs to the DDB1 family.