Figure 1.

Select redox signaling pathways underlying sarcopenia. Lines between boxes indicate signaling pathway connections. Arrowheads represent an increase or promotion, while block heads represent inhibition. Dashed lines indicate pathways with a minor or negligible role in sarcopenia. Arrows within boxes show changes in sarcopenia based on upstream signals. Abbreviations: AMPK: 5′ adenosine monophosphate-activated protein kinase; Ca²⁺: calcium ions; CD38: cluster of differentiation 38; H₂O₂: hydrogen peroxide; mTOR: mechanistic target of rapamyacin; NAD⁺: nicotinamide adenine dinucleotide; NF-κB: nuclear factor kappa-light-chain-enhancer of activated B cells; NMJ: neuromuscular junction; Nrf2: nuclear factor erythroid 2-related factor 2; PGC-1α: peroxisome proliferator-activated receptor gamma coactivator 1-alpha; ROS: reactive oxygen species; SIRT: sirtuin; TNFα: tumor necrosis factor alpha; UPS: ubiquitin-proteosome system.