FEN1 (Flap Endonuclease 1) is a key DNA repair enzyme essential for DNA replication and repair processes[1]. As a structure-specific nuclease, FEN1 processes flap structures during DNA replication and repair. Dysregulation of FEN1 has been strongly implicated in neurodegeneration, cancer predisposition, and aging[2].
FEN1 possesses multiple enzymatic functions essential for genome stability:
FEN1's catalytic activities are mediated by conserved domains:
FEN1 dysfunction significantly contributes to Alzheimer's disease pathogenesis:
DNA Damage Accumulation: Impaired FEN1 activity leads to accumulation of DNA damage in neurons, accelerating neurodegeneration[2:1]. Neurons are particularly vulnerable due to their post-mitotic state.
Genomic Instability: FEN1 deficiency promotes chromosomal instability that may contribute to tau pathology and neuronal dysfunction.
Cell Cycle Re-entry: DNA damage signaling due to FEN1 dysfunction can trigger inappropriate cell cycle re-entry in neurons, leading to apoptosis.
Mitochondrial Dysfunction: FEN1 mutations affect mitochondrial DNA repair, compounding mitochondrial dysfunction in AD.
In Parkinson's disease, FEN1 plays a protective role:
Dopaminergic Neuron Survival: FEN1 activity is crucial for maintaining genomic integrity in dopaminergic neurons, which are particularly vulnerable to oxidative stress.
α-Synuclein Interactions: DNA damage can promote α-synuclein aggregation, and FEN1 dysfunction may accelerate this process[3].
Mitochondrial DNA Repair: FEN1 deficiency in mitochondria promotes accumulation of mitochondrial DNA mutations in dopaminergic neurons.
FEN1 involvement in ALS includes:
Motor Neuron Vulnerability: FEN1 dysfunction exacerbates DNA damage accumulation in motor neurons.
Oxidative Stress: The high metabolic demand of motor neurons makes them particularly sensitive to FEN1 deficiency under oxidative stress conditions.
RNA Processing: FEN1's role in processing R-loops may affect RNA metabolism relevant to TDP-43 pathology.
FEN1 sits at the nexus of DNA damage response and neurodegeneration:
FEN1 mutations cause cancer predisposition syndromes:
FEN1-based therapeutic strategies include:
Key research areas include:
Liu Y, et al. Human FEN1: structure, function, and application in DNA repair. Gene. 2000. 2000. ↩︎
Mastroeni D, et al. DNA damage in Alzheimer's disease and neurodegeneration. Journal of Alzheimer's Disease. 2018. 2018. ↩︎ ↩︎
Wong A, et al. Alpha-synuclein and DNA damage: a vicious cycle in Parkinson's disease. Brain Research. 2019. 2019. ↩︎