Study summary · research use only
Signal transduction pathways that regulate muscle growth
Plain-language summary
Paraphrased from the published abstract below — not a verdict on whether anything works.
This review (human physiology context) discusses signal transduction pathways regulating muscle growth. The authors state that progressive high-resistance exercise with 8-12 repetitions per set to near failure for beginners and 1-12 repetitions for athletes increases muscle protein synthesis for up to 72 h, and that about 20 g of protein, especially ingested directly after exercise, promotes growth by elevating protein synthesis above breakdown. They describe muscle growth as regulated by signaling pathways sensing local and systemic signals, with the main mechanisms being phosphorylation by kinases and dephosphorylation by phosphatases. Growth is described as stimulated by the mTOR system, which senses IGF-1/MGF/insulin, mechanical signals, amino acids, and muscle energy state and regulates protein synthesis, and as opposed by myostatin-Smad signaling that inhibits muscle growth via gene transcription.
Abstract
Progressive high-resistance exercise with 8-12 repetitions per set to near failure for beginners and 1-12 repetitions for athletes will increase muscle protein synthesis for up to 72 h; approx. 20 g of protein, especially when ingested directly after exercise, will promote high growth by elevating protein synthesis above breakdown. Muscle growth is regulated by signal transduction pathways that sense and compute local and systemic signals and regulate various cellular functions. The main signalling mechanisms are the phosphorylation of serine, threonine and tyrosine residues by kinases and their dephosphorylation by phosphatases. Muscle growth is stimulated by the mTOR (mammalian target of rapamycin) system, which senses (i) IGF-1 (insulin-like growth factor 1)/MGF (mechano-growth factor)/insulin and/or (ii) mechanical signals, (iii) amino acids and (iv) the energetic state of the muscle, and regulates protein synthesis accordingly. The action of the mTOR system is opposed by myostatin-Smad signalling which inhibits muscle growth via gene transcription.
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