| Aspect | Findings |
|---|---|
| identity/domains | - Human **DTL** corresponds to UniProt **Q9NZJ0** and is explicitly identified in recent literature as **CDT2/DCAF2/RAMP**, a **DDB1- and CUL4-associated factor (DCAF)** within the CRL4 system (pqac-00000012, pqac-00000011)  <br>- It belongs to the **WD40/DCAF substrate-receptor class**, consistent with the UniProt WD-repeat family/domain assignment and literature describing DTL/CDT2 as a WD40-containing CRL4 receptor (pqac-00000012, pqac-00000006) |
| complex | - DTL functions as the **substrate receptor/adaptor** of the **CRL4^CDT2** E3 ubiquitin ligase built around **CUL4–DDB1** (pqac-00000001, pqac-00000004)  <br>- This complex mediates ubiquitin-dependent proteolysis of replication- and repair-linked proteins to preserve genome stability (pqac-00000001, pqac-00000012) |
| mechanism | - Core mechanism is **PCNA-coupled proteolysis**: DTL recognizes substrates engaged with **chromatin-bound PCNA** and promotes their ubiquitination and proteasomal degradation (pqac-00000001, pqac-00000004)  <br>- Canonical substrates carry a **PIP-degron** (PIP box plus basic residue motif), which binds PCNA with higher affinity than standard PIP motifs and creates a degron for CRL4^CDT2 (pqac-00000004, pqac-00000005)  <br>- Image-based PLA data support **CDT2 proximity to PCNA at replication forks**, reinforcing PCNA as the recruitment platform (pqac-00000015) |
| key substrates | - Best-established substrates are **CDT1**, **p21/CDKN1A**, and **SET8/PR-Set7/KMT5A** (pqac-00000001, pqac-00000004)  <br>- Additional reported substrates/targets in disease contexts include **E2F1**, **PDCD4**, **SLTM**, and **RUVBL1** (pqac-00000003, pqac-00000013)  <br>- SET8 turnover is especially important because SET8 is the **sole H4K20 monomethyltransferase**, linking DTL to chromatin state and fork protection (pqac-00000005) |
| localization | - DTL acts mainly in the **nucleus/on chromatin at replication forks** through association with PCNA during DNA synthesis and repair synthesis (pqac-00000001, pqac-00000015)  <br>- In HCC tissue, DTL protein was reported as mainly **cytoplasmic in paracancer tissue** but elevated in **both cytoplasm and nucleus** in tumors; stronger nuclear localization associated with worse survival (pqac-00000009) |
| pathways/biological processes | - Principal functions cluster in **DNA replication licensing**, **S-phase progression**, **DNA damage responses**, **replication stress tolerance**, and **genome stability maintenance** (pqac-00000004, pqac-00000012)  <br>- By degrading CDT1, p21, and SET8, DTL helps prevent **re-replication**, coordinate checkpoint/cell-cycle transitions, and regulate chromatin during replication (pqac-00000004, pqac-00000005)  <br>- GSEA/pan-cancer analyses linked DTL to **cell cycle**, **G2/M checkpoint**, **E2F targets**, **mTORC1 signaling**, **oocyte meiosis**, and **pyrimidine metabolism** (pqac-00000012) |
| recent 2023-2024 developments | - **2023:** DCAF14 was shown to restrain CRL4^CDT2 activity; loss of DCAF14 causes excessive degradation of SET8/p21/CDT1 and **fork collapse under replication stress** (pqac-00000002, pqac-00000005)  <br>- **2024:** In breast cancer, DTL-mediated **RUVBL1 ubiquitination** promoted a shift toward **NHEJ gene transcription** and radiation resistance (pqac-00000013)  <br>- **2024:** In HCC, **hypoxia/HIF-1α-induced DTL** promoted proliferation, metastasis, and **sorafenib resistance** via **SLTM degradation** and Notch activation (pqac-00000003) |
| disease/clinical relevance | - DTL is repeatedly reported as **overexpressed across many tumor types** and associated with poor prognosis, proliferation, genomic instability, and aggressive disease biology (pqac-00000012, pqac-00000003)  <br>- HCC-focused studies linked high DTL expression to poorer overall survival and to cell-cycle/proliferative programs (pqac-00000009, pqac-00000011)  <br>- Pan-cancer analyses also associate DTL with **immune infiltration** and possible relevance to **immunotherapy response** (pqac-00000012) |
| actionable/therapeutic angles | - **Cullin/neddylation inhibition** (e.g., **MLN4924/pevonedistat**) stabilizes CRL4^CDT2 substrates and is widely used experimentally to blunt DTL-dependent proteolysis, supporting pathway tractability (pqac-00000002, pqac-00000005)  <br>- Recent cancer studies propose DTL as a candidate **biomarker** and possible **therapeutic target** in HCC and breast cancer, including potential radiosensitization by targeting the **DTL–RUVBL1/2–β-catenin** axis (pqac-00000003, pqac-00000013)  <br>- Indirect strategies include modulating upstream regulators such as **HIF-1α** or **E2F1**, or targeting the **PCNA-coupled degradation interface** (pqac-00000003, pqac-00000011) |
| key quantitative stats | - **HCC TCGA dataset:** DTL mRNA reported as **8.51 vs 4.88** in tumor vs adjacent tissue, from **474 cancer** and **50 adjacent** samples; survival analysis used **n=363** patients split into **181 low** and **182 high** DTL groups (pqac-00000009)  <br>- **HCC protein cohort:** tissue microarray included **94 HCC** and **86 adjacent** specimens; follow-up was **4–6.7 years** (pqac-00000011)  <br>- **2024 HCC study:** clinical cohort size **n=209**; **2024 breast cancer RT study:** **7 mice/group**, five **3 Gy** fractions, tumors collected **4 h** after the final irradiation (pqac-00000003, pqac-00000013) |


*Table: This table summarizes verified identity, mechanism, substrates, localization, pathways, and recent disease-relevant findings for human DTL/CDT2/DCAF2. It is useful as a compact evidence map for functional annotation and translational interpretation.*