mTORC1 activation affects the PKB/Akt and PGC1 pathways. (A) Western blot analysis of soleus muscles from 90-day-old control (ctrl) and TSCmKO mice using antibodies directed against the proteins indicated. α-actinin is used as loading control. (B, C) Relative mRNA expression of atrogin-1/MAFbx ( Atr-1) and MuRF1 in TA and soleus muscles of TSCmKO and control mice. All values were normalized to the expression of β-actin and control muscles were set to 100% (TA: N ≥4 mice; Sol: N ≥5 mice). (D, E) Relative mRNA expression of Pgc1α and Pgc1β is shown in TA (D) and soleus (E) muscles of TSCmKO and control mice. All values are normalized to expression of β-actin. Relative expression in muscles from control littermates were set to 100%. TA: N ≥4; Sol: N ≥5. Note that levels of Pgc1β but not Pgc1α are up-regulated in TSCmKO mice. (F) Relative mRNA levels of Pgc1α in differentiated C2C12 cells that were infected with adenoviral vectors encoding GFP (ad-GFP), PGC1β (ad-PGC1β), shRNA to a scrambled sequence (ad-siScr) or shRNA to Pgc1β (ad-siPGC1β). Values are normalized to each control (ad-GFP and ad-siScr) and were set to 100% (N = 9). Note that expression of Pgc1α inversely correlates with PGC1β levels. Quantitative data (B-F) represent mean ± SEM. P-values are ***P <0.001; **P <0.01; *P <0.05; Student’s t-test. (G) NADH-TR staining of TA and soleus muscles of 90-day-old control and TSCmKO mice. Both muscles of TSCmKO are more oxidative. Scale bar = 50 μm.