Fig. 6

Protein degradation pathways are activated with acute inhibition of DRP1 in adult muscles. a The total protein extracts from adult muscles were immunoblotted with indicated antibodies. A representative immunoblot of four independent experiments is shown. Statistical significance, of specified densitometric ratios is indicated with asterisks on the right. b In vivo SUnSET technique shows no differences in protein synthesis rate during adulthood (n = 4). c Representative immunoblot (n = 4) and RT-PCR analysis (n ≥ 5) (d) showing the activation of the unfolded protein response and the upregulation of FGF21 in DRP1 KO muscles. e Immunoblot and densitometric quantification showing the accumulation of FoxO3 in the nuclear fraction of tibialis anterior muscles from Drp1^−/− mice (n = 5 each condition). f RT-PCR analysis of transcriptional levels of the muscle-specific ubiquitin ligases Atrogin1 and MuRF1 and the novel ubiquitin–ligases MUSA1, SMART, FbxO31, TRIM37, and Itch. The data represent average ± SEM (at least n = 5 per condition). g Quantitative PCR analysis of autophagy-related transcripts showing a significant induction of autophagy markers in Drp1^−/−. h Western blot analysis of autophagy marker showing an impaired autophagy in Drp1^−/− (WT, n = 4; KO, n = 5). i Immunoblots and relative densitometric quantification from colchicine treated mice support a block in autophagic flux after Drp1 inhibition (n ≥ 5 mice per each condition). j Keima assay indicating the decreased mitophagy in DRP1-KO myofibers (WT, n = 41; KO, n = 39). Two-tailed unpaired Student’s t test was used. Statistical significance: **p ≤ 0.01; ***p ≤ 0.001