Nfe2l1-mediated proteasome function controls muscle energy metabolism in obesity

Muscle function is an important denominator of energy balance and metabolic health. Adapting the proteome to energetic challenges, in response to diet or fasting, is facilitated by programs of proteostasis, but the adaptive role of the ubiquitin-proteasome system (UPS) in muscle remains unclear. Here, using a multi-omics approach, we uncover that the distinct metabolic condition of obesity is associated with recalibration of the UPS in muscle. Interestingly, obesity is associated with the activation of the transcription factor Nuclear factor, erythroid derived 2,- like 1 (Nfe2l1, also known as Nrf1), and loss of myocyte Nfe2l1 diminishes proteasomal activity and leads to hyperubiquitylation. Mice lacking Nfe2l1 display hormetic energy metabolism and resistance to diet-induced obesity, associated with a lean phenotype and muscle fiber type switching. In conclusion, we define a new adaptive role for UPS in remolding of muscle proteome and function, which is controlled by fine-tuning of proteasome function by Nfe2l1.