TDP2 (Tyrosyl-DNA Phosphodiesterase 2), also known as TTRAP (TNF Receptor-Associated Protein) or EAP-II, is a critical DNA repair enzyme specialized in resolving topoisomerase II (TOP2)-induced DNA damage. Located on chromosome 6p22.3, this enzyme plays an essential role in maintaining genomic stability in post-mitotic neurons, which are particularly vulnerable to accumulated DNA damage due to their inability to divide and replace themselves.
| Tyrosyl-DNA Phosphodiesterase 2 | |
|---|---|
| Gene Symbol | TDP2 |
| Full Name | tyrosyl-DNA phosphodiesterase 2 |
| Chromosome | 6p22.3 |
| NCBI Gene ID | [51567](https://www.ncbi.nlm.nih.gov/gene/51567) |
| OMIM | 614675 |
| Ensembl ID | ENSG00000111802 |
| UniProt ID | [Q9H2P2](https://www.uniprot.org/uniprot/Q9H2P2) |
| Protein Length | 362 amino acids |
| Molecular Weight | 40.5 kDa |
| Associated Diseases | Amyotrophic Lateral Sclerosis, Parkinson's Disease, Ataxia, Alzheimer's Disease |
The TDP2 gene spans approximately 12.5 kb and consists of 9 exons. The gene encodes a 362-amino acid protein with a molecular weight of approximately 40.5 kDa. The promoter region contains several transcription factor binding sites, including p53-responsive elements, indicating its regulation in response to DNA damage [1].
The TDP2 protein contains several key structural features:
The three-dimensional structure reveals a α/β-fold with a central β-sheet surrounded by α-helices, characteristic of the metallo-hydrolase family [2].
TDP2 is a Mg²⁺-dependent phosphodiesterase that specifically catalyzes the removal of covalent TOP2-DNA adducts ( TOP2 cleavage complexes, or TOP2cc). The reaction mechanism involves:
This enzymatic activity is distinct from TDP1 (Tyrosyl-DNA Phosphodiesterase 1), which resolves TOP1-DNA adducts. Together, these two enzymes provide comprehensive protection against topoisomerase-induced DNA damage [3].
TDP2 demonstrates high specificity for:
Topoisomerase II is essential for resolving DNA supercoils during transcription, replication, and chromosome segregation. The enzyme creates double-strand breaks (DSBs) as an intermediate in its catalytic cycle, temporarily passing one DNA duplex through another. Under normal conditions, these DSBs are rapidly resealed. However, various conditions can trap TOP2cc:
The resolution of TOP2cc proceeds through a dedicated repair pathway:
When TDP2 is deficient or overwhelmed:
TDP2 is ubiquitously expressed with highest levels in:
Within neurons, TDP2 localizes to:
Multiple lines of evidence implicate TDP2 dysfunction in ALS:
The mechanism involves failure to resolve TOP2-induced DSBs, leading to genomic instability, activation of DNA damage response pathways, and ultimately neuronal apoptosis [5].
TDP2's role in PD is emerging through several mechanisms:
Recent studies using patient-derived dopaminergic neurons demonstrate increased sensitivity to TOP2 poisons when TDP2 is suppressed [6].
In AD, TDP2 dysfunction contributes through:
The accumulation of DNA damage in AD brains correlates with cognitive decline and is considered a key feature of the disease [7].
Biallelic TDP2 mutations cause a hereditary ataxia syndrome characterized by:
The disease mechanism involves complete loss of TDP2 function, leading to catastrophic accumulation of TOP2cc during normal neural development [8].
TDP2 interacts with numerous cellular proteins:
| Partner | Interaction Type | Function |
|---|---|---|
| p53 | Direct binding | Transcriptional activation of DNA repair genes |
| NF-κB | Direct binding | Modulates inflammatory responses |
| XRCC1 | Complex formation | Coordinates DSB repair |
| DNA-PKcs | Substrate | Involved in NHEJ pathway |
| PARP1 | Activation | DNA damage signaling |
| TDP1 | Cooperativity | Parallel TOP1/TOP2 repair |
TDP2 participates in several key cellular pathways:
TDP2 inhibitors are being developed as:
Strategies to enhance TDP2 activity:
Potential neuroprotective strategies include:
Current research focuses on:
Zhang et al. TDP2 and DNA repair in neurons (2020). 2020. ↩︎
Brown et al. TDP2 function and neurological disease (2020). 2020. ↩︎
Wang et al. Tyrosyl-DNA phosphodiesterases in neurodegeneration (2019). 2019. ↩︎
Miller et al. TDP2 polymorphisms and susceptibility to neurodegenerative diseases (2023). 2023. ↩︎
Johnson et al. Topoisomerase inhibitors for neurodegeneration (2021). 2021. ↩︎
Chen et al. Topoisomerase II dysfunction in Parkinson's disease dopaminergic neurons (2024). 2024. ↩︎
Liu et al. DNA damage response in AD (2021). 2021. ↩︎
Patel et al. DNA topoisomerase II in aging and neurodegeneration (2022). 2022. ↩︎