mTOR
Definition
mTOR, short for mechanistic target of rapamycin, is a protein kinase that helps cells sense nutrients, growth factors, energy status, and other environmental signals. It acts as a central regulator of cell growth, protein synthesis, metabolism, autophagy, and survival. mTOR functions mainly through two related protein complexes, called mTORC1 and mTORC2. [1] [2] [3]
Why It Matters in Ageing Research
mTOR matters in ageing research because it sits at the intersection of nutrient sensing, growth, repair, and stress response. In many model organisms, reduced mTOR signalling has been linked with longer lifespan or improved healthspan, and rapamycin is studied partly because it inhibits mTORC1. However, mTOR is not simply a harmful pathway: it is also necessary for normal growth, immune function, tissue repair, and metabolism. The central question in longevity research is not whether mTOR should be permanently switched off, but how mTOR activity is regulated across tissues, doses, timing, and contexts. [4] [5] [6] [7]
Common Confusion
- mTOR is not the same thing as rapamycin; rapamycin is a drug that can inhibit part of the mTOR pathway.
- mTORC1 and mTORC2 are related but not identical, and they can have different biological roles.
- Lower mTOR signalling is not automatically better in every tissue, person, or situation.
Related Reading
References
- Soliman, G. A. (2013). The role of mechanistic target of rapamycin (mTOR) complexes signaling in the immune responses. https://pmc.ncbi.nlm.nih.gov/articles/PMC3725503/
- Kennedy, B. K., & Lamming, D. W. (2016). The mechanistic target of rapamycin: The grand conducTOR of metabolism and aging. https://pmc.ncbi.nlm.nih.gov/articles/PMC4910876/
- Szwed, A., Kim, E., & Jacinto, E. (2021). Regulation and metabolic functions of mTORC1 and mTORC2. https://pmc.ncbi.nlm.nih.gov/articles/PMC8424549/
- López-Otín, C., et al. (2013). The hallmarks of aging. https://pmc.ncbi.nlm.nih.gov/articles/PMC3836174/
- Lamming, D. W. (2016). Inhibition of the mechanistic target of rapamycin (mTOR)-rapamycin and beyond. https://pmc.ncbi.nlm.nih.gov/articles/PMC4852795/
- Mannick, J. B., et al. (2023). Targeting the biology of aging with mTOR inhibitors. https://pmc.ncbi.nlm.nih.gov/articles/PMC10330278/
- Wang, G., et al. (2022). Mechanistic target of rapamycin complex 1: From a nutrient sensor to a central regulator of metabolism. https://pmc.ncbi.nlm.nih.gov/articles/PMC9526850/
This glossary entry is provided for educational purposes only and does not constitute medical advice.