Research Paper Advance Articles

Figure 4. Aging-related changes in gene or protein expression levels of protein synthesis and degradation markers in the gastrocnemius muscles of female mice. Results of the Western blot analyses for components of the Akt/mechanistic target of the rapamycin (mTOR) pathway, Akt and p70S6 kinase (S6K), in the gastrocnemius muscles of 6- and 24-month-old female mice with PAI-1 gene deficiency (PAI-1^−/−) and their wild-type counterparts (PAI-1^+/+) (A) are shown (n = 9−10 in each group). The protein expression levels of phosphorylated Akt (Ser473), total Akt, phosphorylated S6K (Thr389), and total S6K are expressed as a ratio to GAPDH. Additionally, the phosphorylation rates of Akt (Ser473) and S6K (Thr389) are expressed as a ratio of phosphorylated to total protein levels. pAkt: phosphorylated Akt; pS6K: phosphorylated S6K. Results of real-time PCR analyses for the muscle-specific ubiquitin ligases (B), atrogin-1 and MuRF1, and autophagy-related genes (C), beclin1 and LC3B, in the gastrocnemius muscles of 6- and 24-month-old female PAI-1^+/+ and PAI-1^−/− mice are shown (n = 9−10 in each group). The expression levels of atrogin-1, MuRF1, beclin1, and LC3B mRNA are expressed as a ratio to 18S rRNA. Data are presented as mean ± standard error of the mean. ^**P < 0.01 and ^*P < 0.05.