Pathway link TRANSL-MUSCLE
Protein synthesis Muscle growth
Protein synthesis activates Muscle growth.
Ongoing protein-building is what physically builds muscle; in mice, the signals that drive it are needed for muscle growth and are enough to cause it. In people, blocking mTOR blunts the rise in muscle protein-building after a single bout of exercise, but how much muscle is gained over months under the drug was not measured.
The conditions it holds under
Mouse (BOD2001) and cultured myotubes (ROM2001). The human study DRU2009 is cited on the step before this one (LOAD-MTORC1): rapamycin blocked the rise in muscle protein synthesis 1-2 h after one bout of contractions (and also blocked ERK1/2). It did not measure muscle growth, so it is not evidence for this arrow.
Requires mechanical load. mTORC1 activation without loading does not reproduce healthy hypertrophy, and constitutive activation alone is not sufficient.
- Time it takes
- days
- Step
- indirect (through steps not drawn here)
- Measured in
- mouse, mouse myotubes
- Reaches people?
- plausible in people, not shown directly
- How settled
- settled in the literature
Studies behind it
| Year | Evidence | Study |
|---|---|---|
| 2001 | A | Akt/mTOR pathway is a crucial regulator of skeletal muscle hypertrophy and can prevent muscle atrophy in vivoBOD2001 Akt/mTOR signalling is necessary and sufficient to drive skeletal-muscle hypertrophy and counteract atrophy in vivo. |
| 2001 | M | Mediation of IGF-1-induced skeletal myotube hypertrophy by PI(3)K/Akt/mTOR and PI(3)K/Akt/GSK3 pathwaysROM2001 Shows IGF-1 drives muscle fiber hypertrophy through Akt, via both the mTOR and GSK3 branches, in cultured myotubes, establishing mTOR as a central node for muscle growth signaling. |
Points the other way
| Year | Evidence | Study |
|---|---|---|
| 2026 | A | Feeding-Induced Muscle mTORC1 Signaling Regulates Postprandial Protein Synthesis and Endurance but Not Muscle SizeLAP2026 Using a mouse model expressing an AKT-nonphosphorylatable TSC2 mutant specifically in skeletal muscle, the Manning lab genetically separated feeding-induced from contraction-induced mTORC1 activation. AKT-mediated TSC2 phosphorylation is required for feeding (but not contraction) to activate muscle mTORC1 and drive postprandial protein synthesis — yet mice lacking this feeding-induced signal have normal muscle mass and myofiber size, and instead show improved maximal endurance capacity with a modest rise in mitochondrial content. The finding dissociates mTORC1's role in postprandial anabolism from its role in maintaining steady-state muscle mass, and is a directly relevant data point for whether the pattern/source of mTORC1 activation (feeding vs. mechanical) — not just its average level — shapes downstream outcomes. |
Who has checked this
- Checked by
- No researcher outside the project has checked this link yet.
- Curator sign-off
- Not signed off yet. This link was drafted with AI help and has not been reviewed link by link; treat it as a proposal until it is.
- Curated by
- Oliver Barton, with AI help for drafting; see how links are checked.
← The whole pathway · This link as JSON
Thank you. Your answer was counted anonymously.
Thank you. That helps us know which pages have been read by someone who knows the work.
Thank you. We will check it and correct the page.