Gene

Metabolite

Cell biology

Biology

Citric acid cycle

Endocrinology

Apoptosis

Metabolism

Autophagy

Biochemistry

Calorie restriction

Genetics

Alpha ketoglutarate

Longevity

Mutant

Enzyme

Mitochondrion

Caenorhabditis elegans

Protein subunit

Adenosine triphosphate

ATPase

ATP synthase

Nature

Ageing in the worm Caenorhabditis elegans is shown to be delayed by supplementation with α-ketoglutarate, an effect that is probably mediated by ATP synthase—which is identified as a direct target of α-ketoglutarate—and target of rapamycin (TOR). Calorie restriction can extend lifespan and delay age-related deterioration in a range of organisms. A few small-molecule metabolites have been shown to regulate the ageing process, but little is known about the mechanisms involved. Here Jing Huang and colleagues report that the tricarboxylic acid cycle intermediate α-ketoglutarate (α-KG) extends the lifespan of adult Caenorhabditis elegans roundworms by approximately 50%. The molecular target of α-KG is the β subunit of ATPase. α-KG is dependent on the TOR (target of rapamycin) pathway and it does not extend the lifespan of dietary-restricted animals, suggesting a link between the effects of α-KG and starvation/dietary restriction. Metabolism and ageing are intimately linked. Compared with ad libitum feeding, dietary restriction consistently extends lifespan and delays age-related diseases in evolutionarily diverse organisms1,2. Similar conditions of nutrient limitation and genetic or pharmacological perturbations of nutrient or energy metabolism also have longevity benefits3,4. Recently, several metabolites have been identified that modulate ageing5,6; however, the molecular mechanisms underlying this are largely undefined. Here we show that α-ketoglutarate (α-KG), a tricarboxylic acid cycle intermediate, extends the lifespan of adult Caenorhabditis elegans. ATP synthase subunit β is identified as a novel binding protein of α-KG using a small-molecule target identification strategy termed drug affinity responsive target stability (DARTS)7. The ATP synthase, also known as complex V of the mitochondrial electron transport chain, is the main cellular energy-generating machinery and is highly conserved throughout evolution8,9. Although complete loss of mitochondrial function is detrimental, partial suppression of the electron transport chain has been shown to extend C. elegans lifespan10,11,12,13. We show that α-KG inhibits ATP synthase and, similar to ATP synthase knockdown, inhibition by α-KG leads to reduced ATP content, decreased oxygen consumption, and increased autophagy in both C. elegans and mammalian cells. We provide evidence that the lifespan increase by α-KG requires ATP synthase subunit β and is dependent on target of rapamycin (TOR) downstream. Endogenous α-KG levels are increased on starvation and α-KG does not extend the lifespan of dietary-restricted animals, indicating that α-KG is a key metabolite that mediates longevity by dietary restriction. Our analyses uncover new molecular links between a common metabolite, a universal cellular energy generator and dietary restriction in the regulation of organismal lifespan, thus suggesting new strategies for the prevention and treatment of ageing and age-related diseases.

The metabolite α-ketoglutarate extends lifespan by inhibiting ATP synthase and TOR