Abstract

Simple SummaryStarvation triggers profound metabolic reprogramming in skeletal muscle to sustain survival during nutrient scarcity, yet the role of lysine β-hydroxybutyrylation (Kbhb)—a metabolite-derived post-translational modification (PTM) linked to ketone metabolism—remains unclear. Here, we performed integrative quantitative proteomics and Kbhb profiling on gastrocnemius muscle from mice subjected to 72 h food deprivation. Starvation induced muscle atrophy, elevated systemic β-hydroxybutyrate levels, and widespread changes in Kbhb modification. Proteomic analysis revealed a shift from anabolic to catabolic/oxidative pathways, with downregulation of ribosomal proteins and upregulation of autophagy/lipid catabolism. Deep Kbhb profiling identified over 7500 modified sites across 2000 proteins, with starvation enhancing Kbhb on key metabolic enzymes (glycolysis, TCA cycle, fatty acid β-oxidation) at conserved residues proximal to functional domains, and reducing Kbhb on structural/contractile proteins. Our findings establish Kbhb as a dynamic PTM mediating gastrocnemius muscle adaptation to energy deficiency, expanding the role of metabolite-driven regulation in muscle metabolism.Starvation elicits profound metabolic adaptations in skeletal muscle, enabling survival during nutrient scarcity. While global proteomic changes underpinning muscle atrophy have been studied, the role of lysine β-hydroxybutyrylation (Kbhb), a novel metabolite-derived post-translational modification linked to ketone metabolism, remains largely unexplored. In this study, we subjected mice to 72 h of food deprivation and performed integrative quantitative proteomics and Kbhb-modified peptide profiling on gastrocnemius muscle. Starvation induced significant body weight and muscle mass loss, accompanied by increased systemic β-hydroxybutyrate levels and widespread Kbhb modification of muscle proteins. Proteomic analysis revealed extensive downregulation of ribosomal and translation-associated