Pyruvate is a natural suppressor of interferon signaling by inducing STAT1 protein pyruvylation

Glycolysis is a central metabolic pathway that converts glucose into pyruvate. Although pyruvate has been well documented to be a key and terminal metabolite of glycolysis with both energetic and biosynthetic roles, its non-metabolic functions remain unexplored. Here, we report a pyruvate-mediated protein post-translational modification (PTM), protein pyruvylation. We reveal that high glucose-upregulated glycolysis promotes signal transducer and activator of transcription 1 (STAT1) pyruvylation at Lys201 (K201), which blocks STAT1 and signal transducer and activator of transcription 2 (STAT2) interaction, thus suppressing type I interferon (IFN-I) signaling and antiviral immune activity. Consequently, STAT1-K201R knockin mice exhibit enhanced IFN-I antiviral immunity. Importantly, high glucose promotes STAT1 pyruvylation and attenuates immune response to either virus infection or IFN-I treatment in humans. This study identifies the protein pyruvylation modification, reveals a non-metabolic function of the metabolite pyruvate, and provides insights into how high glucose impairs IFN-I antiviral immunity through pyruvate, offering strategies to improve IFN-I immune activity for both preventing and treating viral infections.