Naijin Zhang, Xinyue Huang, Saien Lu, Yuanming Zou, Guozhe Sun, Wei Zhang, Huijun Lu, Limin Wang, Xinxin Lu, Zhaobo Zhang, Cheng Cheng, Shilong You, He Zhang, Ying Zhang, Pengbo Wang, Pan Zhou, Juan Luo, Yuyi Chen, Feng Wu, Jiayan Guo, Anqi Ning, Yushan Guo, Liu Cao, Liming Sun, Yingxian Sun
How fluctuations in central metabolites are transduced into cell-death decisions remains poorly understood. Here we show that lactate directly promotes necroptosis through lactylation of receptor-interacting protein kinase 3 (RIPK3) at lysine 63 (K63). Large-scale screening identified LDH inhibition as a suppressor of mixed lineage kinase domain-like pseudokinase (MLKL)-dependent necroptosis, implicating intracellular lactate as a pivotal modulator. PCAF-mediated K63 lactylation enhances RIPK3 kinase activity and stabilizes the RIPK3-MLKL complex, driving membrane disruption. K63R mutation or PCAF loss potently suppresses necroptosis. This pathway operates in both pathological and physiological contexts: K63R knockin mice and LDH/PCAF inhibition protect against injury in myocardial ischemia-reperfusion and influenza A infection, whereas exercise-induced lactate engages the identical cascade to drive myofiber necroptosis, activating muscle stem cells and enhancing athletic performance. These findings reveal RIPK3-K63 lactylation as a pivotal mechanism linking lactate fluctuations to cell-death outcomes across disease and physiology.