ATP5B encodes the beta subunit of mitochondrial ATP synthase (Complex V), the catalytic subunit responsible for ATP synthesis from ADP and inorganic phosphate. This is the key catalytic component of the ATP synthase complex.
ATP5B is essential for:
- ATP synthesis — the primary function
- Energy metabolism — cellular ATP production
- Mitochondrial function — maintains membrane potential
- Contains three catalytic sites for ATP synthesis
- Undergoes conformational changes during catalysis
- Binds ADP and Pi to generate ATP
- Open (E), Loose (D), and Tight (T) conformations
- ~529 amino acids
- Molecular weight ~56 kDa
- Part of the F1 catalytic domain
- Forms hexameric ring with alpha subunits
- Inhibitory protein (IF1) binding
- Oligomycin sensitivity via OSCP subunit
- ADP/ATP ratios affect activity
- Reduced ATP5B expression in AD brain
- Impaired ATP synthesis
- Contributes to neuronal energy crisis
- Correlates with disease severity
- Mitochondrial dysfunction in substantia nigra
- Reduced ATP production in dopaminergic neurons
- Contributes to cell death
- Mutations can cause ATP synthase deficiency
- Leigh syndrome phenotype
ATP5B is ubiquitously expressed:
- Brain: High in neurons
- Heart: Highest (continuous energy demand)
- Muscle: High
- Liver: High metabolic activity
- Brown et al., ATP synthase in neurodegenerative disease (2014)
- Pedersen et al., ATP synthase and neurodegeneration (2007)