Lithocholic acid (LCA) is accumulated in mammals during calorie restriction and it can activate AMP-activated protein kinase (AMPK) to slow down ageing¹. However, the molecular details of how LCA activates AMPK and induces these biological effects are unclear. Here we show that LCA enhances the activity of sirtuins to deacetylate and subsequently inhibit vacuolar H⁺-ATPase (v-ATPase), which leads to AMPK activation through the lysosomal glucose-sensing pathway. Proteomics analyses of proteins that co-immunoprecipitated with sirtuin 1 (SIRT1) identified TUB-like protein 3 (TULP3), a sirtuin-interacting protein², as a LCA receptor. In detail, LCA-bound TULP3 allosterically activates sirtuins, which then deacetylate the V1E1 subunit of v-ATPase on residues K52, K99 and K191. Muscle-specific expression of a V1E1 mutant (3KR), which mimics the deacetylated state, strongly activates AMPK and rejuvenates muscles in aged mice. In nematodes and flies, LCA depends on the TULP3 homologues tub-1 and ktub, respectively, to activate AMPK and extend lifespan and healthspan. Our study demonstrates that activation of the TULP3–sirtuin–v-ATPase–AMPK pathway by LCA reproduces the benefits of calorie restriction.

石胆酸 （LCA） 在卡路里限制期间在哺乳动物体内积累，它可以激活 AMP 活化蛋白激酶 （AMPK） 以延缓衰老¹。然而，LCA 如何激活 AMPK 并诱导这些生物学效应的分子细节尚不清楚。在这里，我们表明 LCA 增强了去乙酰化酶的活性，随后抑制液泡 H⁺-ATP 酶 （v-ATPase），这导致通过溶酶体葡萄糖感应途径激活 AMPK。对与 sirtuin 1 （SIRT1） 共免疫沉淀的蛋白质组学分析发现，TUB 样蛋白 3 （TULP3）（一种与 sirtuin 相互作用的蛋白²）是 LCA 受体。详细地说，LCA 结合的 TULP3 变构激活去乙酰化酶，然后去乙酰化残基 K52、K99 和 K191 上 v-ATP 酶的 V1E1 亚基。模拟脱乙酰状态的 V1E1 突变体 （3KR） 的肌肉特异性表达强烈激活 AMPK 并使老年小鼠的肌肉恢复活力。在线虫和果蝇中，LCA 分别依赖于 TULP3 同源物 tub-1 和 ktub 来激活 AMPK 并延长寿命和健康寿命。我们的研究表明，LCA 激活 TULP3-sirtuin-v-ATP 酶-AMPK 通路再现了卡路里限制的好处。