Huot, Joshua R.Thompson, BrianMcMullen, CharlotteMarino, Joseph S.Arthur, Susan T.2023-01-192023-01-192021-06-15Huot JR, Thompson B, McMullen C, Marino JS, Arthur ST. GSI Treatment Preserves Protein Synthesis in C2C12 Myotubes. Cells. 2021;10(7):1786. Published 2021 Jul 15. doi:10.3390/cells10071786https://hdl.handle.net/1805/30958It has been demonstrated that inhibiting Notch signaling through γ-secretase inhibitor (GSI) treatment increases myogenesis, AKT/mTOR signaling, and muscle protein synthesis (MPS) in C2C12 myotubes. The purpose of this study was to determine if GSI-mediated effects on myogenesis and MPS are dependent on AKT/mTOR signaling. C2C12 cells were assessed for indices of myotube formation, anabolic signaling, and MPS following GSI treatment in combination with rapamycin and API-1, inhibitors of mTOR and AKT, respectively. GSI treatment increased several indices of myotube fusion and MPS in C2C12 myotubes. GSI-mediated effects on myotube formation and fusion were completely negated by treatment with rapamycin and API-1. Meanwhile, GSI treatment was able to rescue MPS in C2C12 myotubes exposed to rapamycin or rapamycin combined with API-1. Examination of protein expression revealed that GSI treatment was able to rescue pGSK3β Ser9 despite AKT inhibition by API-1. These findings demonstrate that GSI treatment is able to rescue MPS independent of AKT/mTOR signaling, possibly via GSK3β modulation.en-USAttribution 4.0 InternationalMuscle protein synthesisGSImTORAKTArticle