Estimation of p70S6K Thr³⁸⁹ and 4E‐BP1 Thr^37/46 phosphorylation support dependency of tension per se in a dose‐response relationship for downstream mTORC1 signalling

Concomitant excitation and tension development are required for myocellular gene expression and protein synthesis in rat skeletal muscle

“…This suggests that signalling for translation initiation is independent of excitation, Ca 2+ ‐release and active actin‐myosin interaction. This finding is in agreement with recent data from our lab showing that activation of signalling for translation initiation is dependent on tension development per se in a dose‐response manner 36,37 …”

“…35 In another recent study by ourselves, we employed an ex vivo approach and observed similar increases in mTORC1 signalling in response to eccentric contractions (ECC) and passive stretching (PAS) when peak tension and tension-time-integral was equalized. 36,37 In addition, we observed a dose-response relationship between increases in mTORC1 signalling and peak tension during PAS. Collectively, these data suggest that increased tension development is an important independent factor for the initiation of the anabolic process in skeletal muscle.…”

“…In one study, Eftestøl et al (2016) observed a larger hypertrophic response in rat hind limb muscles following 6 weeks of electrically stimulated isometric contractions with high levels of tension development as compared to concentric contractions with lower levels of tension development when neural output was equalized between the contraction modes 35 . In another recent study by ourselves, we employed an ex vivo approach and observed similar increases in mTORC1 signalling in response to eccentric contractions (ECC) and passive stretching (PAS) when peak tension and tension‐time‐integral was equalized 36,37 . In addition, we observed a dose‐response relationship between increases in mTORC1 signalling and peak tension during PAS.…”

“…This finding is in agreement with recent data from our lab showing that activation of signalling for translation initiation is dependent on tension development per se in a dose-response manner. 36,37 Signalling proteins inherent of the mTORC1 signalling pathway have been used as biomarkers of increased muscle protein synthesis and hypertrophy. This contention is founded on observations of a close correlation between the increased p70S6K phosphorylation in response to an acute bout of resistance exercise and the hypertrophic response to prolonged exercise training in both rodent 15 and human 16 models.…”

ASPP2 Coordinates ERS-Mediated Autophagy and Apoptosis Through mTORC1 Pathway in Hepatocyte Injury Induced by TNF-α

“…As another variety of regulatory molecules in the upstream of autophagy, mTORC1 can suppress the initial formation of autophagic vesicles by inhibiting ATG13 ( Odle et al, 2020 ). In addition to inhibiting autophagy, mTORC1 also regulates the growth and proliferation of cells through two different types of downstream molecule, namely, P70S6K and 4E-BP1 ( Rindom et al, 2020 ). In our previous study, it was demonstrated that ASPP2 can regulate liver regeneration and hepatocyte proliferation through mTORC1 pathway ( Shi et al, 2018 ), despite the lack of clarity on whether ASPP2 could regulate autophagy and apoptosis through mTORC1 pathway.…”