Figure 6.
Atrogin-1 and MuRF-1 expression levels do not change in atrophic hearts, but are significantly upregulated in atrophic skeletal muscle. (A) Atrogin-1 and MuRF-1 mRNA fold changes (normalized to 18S expression) in male and female control and atrophic hearts. (B) Relative atrogin-1 and MuRF-1 gene expression at day 27 in male heart and skeletal muscle (gastrocnemius). (C) Western blot of day 15 cardiac muscle lysates for total ubiquitin. Lower panel: Ubiquitin conjugation assays do not show a difference in ubiquitination activity between groups. (D) Proteasome activity in atrophic cardiac and skeletal muscle. Velcade is a potent and specific proteasome inhibitor. n = 4 per group. Mean ± SEM. *p < 0.05, **p < 0.01 vs. control.