FBP1‐Mediated Compartmentalization of Glycolytic Enzyme Complexes Suppresses PKM2 Function to Ameliorate MASLD Progression

ABSTRACT

Metabolic dysfunction‐associated steatotic liver disease (MASLD) is driven by aberrant hepatocyte glycolytic reprogramming. Fructose‐1,6‐bisphosphatase 1 (FBP1), a key gluconeogenic enzyme, has poorly defined roles in MASLD progression. Here, we show that FBP1 is consistently downregulated during MASLD progression, with a progressive decline from MASL to MASH in clinical specimens and key preclinical models. Mechanistically, FBP1 directly interacts with glycolytic enzymes Pyruvate kinase M2 (PKM2), Enolase 1 (ENO1), and Lactate Dehydrogenase A (LDHA) to form compartmentalized complexes, suppressing PKM2 activity and restricting excessive glycolysis and lipid accumulation in hepatocytes. Domain mapping defined the precise interaction interface between FBP1 189–235 aa and PKM2 390–531 aa, and disruption of this binding abrogated FBP1's glycolysis‐repressive effects in hepatocytes. In vivo, only liver‐specific overexpression of enzymatically inactive but binding‐competent FBP1 G260R, not its interaction‐deficient mutant FBP1 G260R‐Δ189‐235, alleviated hepatic steatosis, inflammation, and fibrosis in diet‐induced MASLD mice. This study reveals a non‐canonical function of FBP1 independent of its enzymatic activity in regulating glycolytic complex assembly and identifies the FBP1‐PKM2 interaction as a novel candidate intervention target for MASLD.