APE2 (Apurinic/Apyrimidinic Endonuclease 2), also known as APEX2, is a DNA repair enzyme belonging to the DNA repair endonuclease family. The gene encodes a 517-amino acid protein localized primarily to the nucleus and mitochondria. APE2 plays a critical role in base excision repair (BER), the primary pathway for repairing small, non-bulky DNA lesions caused by oxidative damage, alkylation, and spontaneous base loss (AP sites).
The APE2 gene is located on chromosome 6p25.2 and encodes a 517-amino acid protein with a molecular weight of approximately 56 kDa. The protein contains: [1]
APE2 shares structural and functional homology with the well-characterized APE1 (APEX1), though APE2 has distinct biological functions. [2]
In the nervous system, APE2 is crucial for: [3]
Base Excision Repair (BER): APE2 cleaves AP sites (abasic sites) in DNA, creating a single-strand break that is subsequently processed by DNA polymerase and ligase
Mitochondrial DNA Repair: APE2 localizes to mitochondria where it maintains mitochondrial DNA (mtDNA) integrity. Neurons are highly dependent on mitochondrial function
Response to Oxidative Stress: Neurons generate high levels of reactive oxygen species (ROS) from mitochondrial metabolism. APE2 helps repair oxidative DNA damage
Transcriptional Regulation: APE2 interacts with transcription factors to modulate gene expression in response to DNA damage
APE2 has been implicated in Alzheimer's disease (AD) through multiple mechanisms: [4]
In Parkinson's disease (PD), APE2 may play protective roles:
APE2 dysregulation has been reported in ALS:
Recent studies link APE2 to ataxia-telangiectasia (AT)-like disorder, emphasizing its role in neuronal survival.
APE2 represents a potential therapeutic target:
APE2 is expressed in all tissues, with high expression in:
Subcellular localization: both nuclear and mitochondrial compartments.
APE2 interacts with:
APE2 is a critical DNA repair enzyme that protects neurons from oxidative DNA damage. Its role in both nuclear and mitochondrial DNA repair makes it essential for neuronal survival, and dysfunction contributes to neurodegenerative diseases including AD, PD, and ALS.
Thapa et al. APE2 and Alzheimer's disease (2019). 2019. ↩︎
Cheng et al. Mitochondrial APE2 in neurodegeneration (2022). 2022. ↩︎
Yang et al. APE2 deficiency and oxidative stress (2021). 2021. ↩︎
Li et al. DNA repair in Parkinson's disease (2023). 2023. ↩︎