Caspase 2 is a protein that caspase 2 has diverse cellular functions beyond apoptosis:. This page describes its structure, normal nervous system function, role in neurodegenerative disease, and potential as a therapeutic target.
Caspase 2 is an evolutionarily conserved caspase with unique features:
- Prodomain: Long N-terminal prodomain (~165 aa) containing a CARD (Caspase Recruitment Domain)
- Large subunit (p19): ~19 kDa catalytic subdomain
- Small subunit (p12): ~12 kDa subunit
- Active heterotetramer: p19₂p12₂ forms the active enzyme
Caspase 2 is the most conserved caspase across species and is unique among caspases in its ability to be activated by multiple mechanisms.
Caspase 2 has diverse cellular functions beyond apoptosis:
- Apoptosis initiation: Can initiate apoptosis independently or through the apoptosome
- PIDDosome activation: Forms the PIDDosome complex for caspase-2 activation
- Mitochondrial pathway: Responds to mitochondrial outer membrane permeabilization
¶ DNA Repair and Genome Stability
- p53 activation: Cooperates with p53 in DNA damage response
- Checkpoint regulation: Links DNA damage to apoptosis
- Tumor suppression: Acts as a tumor suppressor
- Metabolic regulation: Affects cellular metabolism
- Endoplasmic reticulum stress: Responds to ER stress
- Pyroptosis: Can mediate inflammasome-independent pyroptosis
Caspase 2 plays a critical role in HD pathogenesis:
- Mutant huntingtin cleavage: Caspase 2 cleaves mutant huntingtin protein
- Toxic fragment generation: Cleavage generates toxic fragments that accumulate
- Neuronal death: Contributes to striatal and cortical neuron loss
- Therapeutic target: Caspase-2 inhibitors show promise in HD models
- Amyloid-beta toxicity: Mediates Aβ-induced neuronal apoptosis
- Tau cleavage: Can cleave tau protein
- Synaptic loss: Contributes to synaptic dysfunction
- Dopaminergic neuron death: Mediates apoptosis in substantia nigra neurons
- Alpha-synuclein toxicity: Interacts with α-syn aggregation pathways
- Mitochondrial dysfunction: Links mitochondrial damage to apoptosis
- Motoneuron degeneration: Contributes to motoneuron death
- SOD1 toxicity: Mediates mutant SOD1-induced apoptosis
- Caspase-2 inhibitors: Z-VDVAD-FMK and other peptide inhibitors
- Non-peptidic inhibitors: Small molecule approaches
- Gene silencing: siRNA and antisense oligonucleotides
- Neuroprotective strategies: Combined approaches targeting multiple cell death pathways
- Graham et al., Caspase-2 is the initiating caspase in Huntington's disease (2008)
- Troy et al., Caspase-2 in neurodegeneration (2009)
- Zheng et al., Caspase-2 deficiency enhances amyloid-beta pathology (2014)
- Sullivan et al., Caspase-2: A potential therapeutic target in Parkinson's disease (2020)
- Puentes et al., Caspase-2 in ALS: Friend or foe? (2019)