MOTS-c broke a fundamental assumption in biology when it was discovered in 2015: that mitochondrial DNA only encodes proteins involved in the electron transport chain. Instead, researchers found that mitochondria produce a signaling peptide that communicates with the nucleus and the rest of the body — regulating metabolism, insulin sensitivity, and the aging process itself.
What Is MOTS-c?
MOTS-c (Mitochondrial Open reading frame of the Twelve S rRNA type-c) is a 16-amino-acid peptide encoded within the 12S rRNA gene of mitochondrial DNA. It was discovered by Dr. Changhan David Lee and colleagues at the University of Southern California and published in Cell Metabolism in 2015. It was the first mitochondrial-derived peptide (MDP) shown to regulate cellular metabolism and nuclear gene expression — establishing an entirely new category of retrograde signaling from mitochondria to the nucleus.[1]
How MOTS-c Works
AMPK Activation: MOTS-c’s primary mechanism is activation of AMP-activated protein kinase (AMPK) — the same metabolic sensor activated by exercise, caloric restriction, and metformin. AMPK is often called the “metabolic master switch” because it regulates energy homeostasis across the entire body. When activated, AMPK stimulates glucose uptake independent of insulin, increases fatty acid oxidation (fat burning), promotes mitochondrial biogenesis (creation of new mitochondria), suppresses mTOR-driven anabolic processes when energy is scarce, and activates autophagy (cellular cleanup and recycling).[2]
Nuclear Translocation: Under metabolic stress, MOTS-c translocates to the cell nucleus where it directly regulates gene expression — particularly genes involved in the antioxidant response (via the ARE/Nrf2 pathway). This mitochondria-to-nucleus signaling represents a feedback system where mitochondria communicate their functional status to the cell’s command center and request appropriate adaptations.[3]
Folate-Methionine Cycle: MOTS-c affects the folate cycle and de novo purine biosynthesis pathway, redirecting cellular metabolism in ways that improve metabolic flexibility — the ability to switch between fuel sources depending on availability. This metabolic reprogramming mirrors what happens during exercise adaptation.[1]
Research Findings
Insulin Sensitivity: In mice fed a high-fat diet, MOTS-c treatment prevented diet-induced insulin resistance and obesity. Treated animals maintained normal glucose tolerance and insulin sensitivity despite the obesogenic diet — effects that were mediated through AMPK-dependent skeletal muscle glucose uptake.[1]
Exercise Performance: A 2020 study published in Nature Communications found that MOTS-c levels increase in skeletal muscle during exercise in humans and that administering MOTS-c to mice improved their physical performance on treadmill tests. The researchers concluded that MOTS-c acts as a mitochondrial signal that enhances metabolic adaptation to physical stress.[4]
Aging: MOTS-c levels decline with age in humans — paralleling the decline in mitochondrial function that characterizes aging. In aged mice, MOTS-c treatment improved physical performance and metabolic parameters, suggesting it may counteract some aspects of age-related metabolic decline.[4]
MOTS-c vs. Other Exercise Mimetics
While SLU-PP-332 activates exercise-like gene expression through ERRγ, MOTS-c activates exercise-like metabolic signaling through AMPK. These are complementary pathways — ERRγ drives the transcriptional adaptations (gene expression changes) while AMPK drives the acute metabolic adaptations (fuel utilization, energy sensing). Both contribute to the full spectrum of exercise benefits.
References
- Lee C, et al. “The mitochondrial-derived peptide MOTS-c promotes metabolic homeostasis and reduces obesity and insulin resistance.” Cell Metabolism. 2015;21(3):443-454.
- Hardie DG, et al. “AMPK: a nutrient and energy sensor that maintains energy homeostasis.” Nature Reviews Molecular Cell Biology. 2012;13(4):251-262.
- Kim KH, et al. “MOTS-c is an exercise-induced mitochondrial encoded regulator of age-dependent physical decline.” Nature Communications. 2020;11:2457.
- Reynolds JC, et al. “MOTS-c is an exercise-induced mitochondrial-encoded regulator of age-dependent physical decline.” Nature Communications. 2021;12:470.
