After consuming 2 grams of leucine, the level of a specific molecular signal in muscle cells at one hour is related to how quickly muscle proteins are built over the next three hours in young, active...
Mechanism
Synthesis from 1 study
Leucine from food tells muscle cells to start building more protein by activating a molecular switch that moves to the edge of the cell and turns on the protein-making machines. How strong that switch is at one hour predicts how much protein the muscle will make over the next three hours.
Most probable mechanism
When leucine enters muscle cells, it triggers a chain reaction that moves a key growth regulator to the edge of the cell, where it turns on a signal that tells the cell's protein-making machinery to work faster, leading to more muscle protein being built.
Leucine is absorbed from the bloodstream into skeletal muscle cells and binds to intracellular sensors that detect amino acid availability.
This binding releases inhibition on a complex that activates Rag GTPases, which direct the mTORC1 protein complex to move to the lysosome and cell periphery.
At the lysosome and cell periphery, mTORC1 becomes fully activated and phosphorylates the ribosomal protein RPS6 at specific sites.
Phosphorylated RPS6 increases the efficiency of ribosomes in initiating the translation of messenger RNA into new muscle proteins.
The level of RPS6 phosphorylation at 60 minutes predicts the rate at which myofibrillar proteins are synthesized over the next 180 minutes.
Evidence from Studies
Supporting (1)
Community contributions welcome
Leucine ingestion promotes mTOR translocation to the periphery and enhances total and peripheral RPS6 phosphorylation in human skeletal muscle
Contradicting (0)
Community contributions welcome
Gold Standard Evidence Needed
According to GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this specific claim, ordered from strongest to weakest evidence.