Hexokinase-2 moonlights as a suppressor of STING-mediated innate immunity.

Metabolic enzymes are increasingly recognized for "moonlighting" functions beyond their primary metabolic roles. While such non-canonical activities are well characterized in cancer biology, their roles in innate immunity remain poorly defined. Here, we show that Hexokinase II (HK2), a rate-limiting enzyme of glycolysis, suppresses STING-mediated innate immune responses independently of its enzymatic activity. Upon STING activation, reactive oxygen species (ROS) trigger the dissociation of HK2 from the mitochondria to the cytosol. Cytosolic HK2 then interacts with STING, impeding its oligomerization and translocation to the Golgi apparatus, thereby dampening downstream immune signaling. Notably, HK-TAT, a peptide that induces HK2 release from the mitochondria, effectively inhibits STING-dependent immune activation and ameliorates disease phenotypes in STING-driven autoimmune mouse models. Our findings highlight the moonlighting role of HK2 as a negative regulator of STING signaling and provide a potential therapeutic approach for treating autoimmune diseases driven by STING dysregulation.