Fig. 2

HDAC4 mediates the activation of ubiquitin-proteasome pathway in skeletal muscle upon denervation. a Proteasome activity in control (CTR) and HDAC4mKO muscles, 1 week following denervation. n = 3–4. b Representative western blot for MHC protein in control (CTR) and HDAC4mKO muscles, 1 week following denervation. Gapdh was used as loading control. c Densitometric measurements of MHC protein, 1 week following denervation. n = 4. d Proteasome activity in control (CTR) and HDAC4mKO muscles, 2 weeks following denervation. Data are shown as mean ± SEM; n = 3–4. Two-way ANOVA revealed an interaction (F = 5.48; df 1; p = 0.03); *p < 0.05 by Tukey’s HSD test. e Representative western blot for MHC protein in control (CTR) and HDAC4mKO muscles, 2 weeks following denervation. Gapdh was used as loading control. f Densitometric measurements of MHC protein, 2 weeks following denervation. n = 4; two-way ANOVA revealed an interaction (F = 4.96; df 1; p = 0.046); *p < 0.05 by Tukey’s HSD test. g Representative pictures of control (CTR) and HDAC4mKO muscles electroporated with Ub-G76 V-YFP (green), a UPS activity reporter and dsRED (red) plasmids, for monitoring the efficiency of electroporation, 2 weeks after denervation. Scale bar = 50 μm. Quantification of green and red positive fibers. n = 3; between 50 and 300 dsRED⁺ fibers were counted per sample. Two-way ANOVA revealed an interaction (F = 5.48; df 1; p = 0.03); *p < 0.05 by Tukey’s HSD test. h Proteasome activity in control (CTR) and HDAC4mKO muscles, 4 weeks following denervation. Data are shown as mean ± SEM; n = 3–4. i Representative western blot for MHC protein in control (CTR) and HDAC4mKO muscles, 4 weeks following denervation. Gapdh was used as loading control. l Densitometric measurements of MHC protein, 4 weeks following denervation. n = 4; two-way ANOVA revealed an interaction (F = 5.25; df 1; p = 0.04); *p < 0.05 by Tukey’s HSD test.