| Complex/Axis | DDB1 role | Key partner(s) | Biological process | Type of evidence (structure/proteomics/review) | Quantitative/statistical highlight | Key citation IDs |
|---|---|---|---|---|---|---|
| UV-DDB / GG-NER | Non-DNA-binding subunit of UV-DDB; scaffolds damage-recognition machinery with DDB2 and links lesion sensing to ubiquitylation steps | DDB2, XPC, CUL4 | Recognition of UV-induced DNA lesions and initiation of global-genome nucleotide excision repair | Review/proteomics-supported functional synthesis | DDB2-associated DCAF interaction can be stimulus-specific under UV damage; myc-BirA*-DDB2 cells showed 12 proteins decreased at 16 h in pulse-SILAC workflow (pqac-00000007) | (pqac-00000001, pqac-00000003, pqac-00000007) |
| CRL4 core adaptor axis | Central adaptor linking CUL4A/B scaffold to WD40 substrate receptors (DCAFs) through H-box recognition; organizes CRL4 E3 ligase architecture | CUL4A, CUL4B, ROC1/RBX1, DCAFs | Ubiquitin-dependent proteostasis across DNA repair, replication, cell cycle, tumorigenesis | Structure + proteomics | CRLs account for ~20% of proteasomal protein degradation; 58 DCAFs characterized, 15/58 showed DDB1/CUL4 interactions, and 10 were enriched for both DDB1 and CUL4A/B (pqac-00000005, pqac-00000007) | (pqac-00000005, pqac-00000007) |
| DDB1 structural architecture | Triple WD40-like β-propeller adaptor (BPA/BPB/BPC); BPB contacts CUL4 N-terminus and creates receptor-binding scaffold | CUL4A/B, substrate receptors such as AMBRA1 | Assembly of multi-subunit E3 ligase complexes | Structure | Cryo-EM structure of DDB1-AMBRA1 solved at 3.08 Å; HDX-MS covered 203 peptides and 98.8% of AMBRA1 sequence (pqac-00000006) | (pqac-00000006, pqac-00000016) |
| CRL4-AMBRA1 | Adaptor that binds AMBRA1 substrate receptor and enables substrate ubiquitination | AMBRA1, Cyclin D1, CUL4A/B-RBX1 | Cell-cycle regulation and coupling of ubiquitin ligase function to AMBRA1 biology | Structure + functional biochemistry | DDB1-binding-defective AMBRA1 mutants blocked Cyclin D1 ubiquitination in vitro and increased cell-cycle progression; structure resolved at 3.08 Å (pqac-00000006) | (pqac-00000006, pqac-00000016) |
| DDB1-CUL4 interactome / DCAF network | Hub for selective assembly with a limited subset of bona fide DCAFs and associated substrates | DDA1, ERCC8, DDB2, multiple WD40 DCAFs | Mapping substrate-receptor usage, chromatin-linked and vesicle/secretory functions | Proteomics | Only 14/58 DCAFs (23%) were enriched in DDB1/CUL4 assays; reciprocal interactomes supported seven high-confidence DCAFs; DDA1 proximity labeling enriched 12 DCAFs (pqac-00000000, pqac-00000012) | (pqac-00000000, pqac-00000012) |
| Replication / cohesion chromatin axis | CRL4-DDB1 complex component supporting chromatin-associated regulation beyond DNA damage recognition | Esco2, DDA1, CUL4 | Replication-coupled sister chromatid cohesion and genome stability | Proteomics/literature synthesis | Reported as a genomic-stability pathway linked to DDB1-CUL4 complexes; no direct effect size given in provided context (pqac-00000001, pqac-00000004) | (pqac-00000001, pqac-00000004) |
| Noncanonical oxidative DNA repair support via UV-DDB | Within UV-DDB, supports DDB2-centered stimulation of BER enzymes at oxidative lesions | DDB2, SMUG1, OGG1, MUTYH, APE1 | Base excision repair of oxidative damage / lesion handoff | Primary mechanistic study summarized in provided context | UV-DDB stimulated OGG1 ~3-fold, MUTYH 4–5-fold, APE1 8-fold, and SMUG1 4–5-fold; reduced SMUG1 DNA residence time by >8-fold (pqac-00000003) | (pqac-00000003) |
| Influenza A virus–rewired CRL4 axis | Core adaptor in host CRL4 complexes rewired during infection; supports non-degradative ubiquitination of viral factor PB2 | DCAF11, DCAF12L1, PB2 | Host–virus interaction and antiviral/ proviral ubiquitin signaling | Proteomics | IAV caused a global loss of DDB1 and DCAF11 interactions while increasing DCAF12L1 associations; DDB1/DCAF11/DCAF12L1 required for optimal in vitro infection (pqac-00000015) | (pqac-00000015) |
| Induced proximity / DDB1-directed degraders | Direct small-molecule engagement point for induced-proximity chemistry; can serve as recruiter in DDB1-dependent degradation | C173-targeting covalent ligand, BRD4, AR, CUL4A-DDB1 | Targeted protein degradation / chemical biology applications | Chemoproteomics + cellular degradation | Covalent recruiter bound DDB1 at C173 and supported BRD4 and AR degradation that was proteasome-, NEDDylation-, and DDB1-dependent; DDB1 noted as essential, potentially limiting resistance (pqac-00000008, pqac-00000010) | (pqac-00000008, pqac-00000010) |
| CDK12–cyclin K–DDB1 molecular glue axis | DDB1 provides a gluable surface in ternary complexes that drive cyclin K degradation | CDK12, cyclin K, CRL4 | Molecular-glue-induced targeted degradation | Review of structural/biochemical studies | >90 compounds screened; 40 had <100 nM biochemical affinity; 28 ternary crystal structures solved; DDB1 Arg928 identified as hotspot residue and degraders contributed ~20% of the PPI interface (pqac-00000009) | (pqac-00000009) |


*Table: This table summarizes the main experimentally supported DDB1 complexes, adaptor roles, and biological functions relevant to human DDB1/Q16531. It emphasizes recent structural, proteomic, and induced-proximity findings, including quantitative highlights useful for functional annotation.*