Functions as a component of numerous distinct DCX (DDB1-CUL4-X-box) E3 ubiquitin-protein ligase complexes which mediate the ubiquitination and subsequent proteasomal degradation of target proteins (PubMed:17452440, PubMed:28437394, PubMed:28302793, PubMed:31686031, PubMed:31819272). In the DCX complexes, acts as a scaffolding subunit required to stabilize the complex (PubMed:31686031, PubMed:31819272). Protein modification; protein ubiquitination. Component of numerous DCX (DDB1-CUL4-X-box) E3 ubiquitin-protein ligase complexes which consist of a core of DDB1, cullin-4 (CUL4A or CUL4B), DDA1 and RBX1 (PubMed:28437394, PubMed:28302793, PubMed:31693891, PubMed:31686031, PubMed:31819272, PubMed:31693911). Component of the DCX(DCAF15) complex, also named CLR4(DCAF15) complex, composed of DCAF15, DDB1, cullin-4 (CUL4A or CUL4B), DDA1 and RBX1 (PubMed:28437394, PubMed:28302793, PubMed:31693891, PubMed:31686031, PubMed:31819272, PubMed:31693911). Part of the DDD core complex containing DET1, DDA1 and DDB1; the DDD core complex recruits a specific UBE2E enzyme, such as UBE2E1, UBE2E2 UBE2E3, to form specific DDD-E2 complexes (PubMed:17452440). Belongs to the DDA1 family.