MOTS-c is one of the mitochondrial-derived peptides, a class of short peptides translated from small open reading frames inside mitochondrial DNA rather than the nuclear genome. Its origin is the experimental interest: it places a signalling molecule inside the organelle whose own genome encodes it, which makes it a tractable model for retrograde communication from mitochondrion to nucleus.

The characterised mechanism runs through one-carbon metabolism. MOTS-c interferes with the folate cycle, causing accumulation of 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR), an endogenous AMP mimetic that activates AMP-activated protein kinase. AMPK activation then shifts substrate handling toward glucose uptake and fatty acid oxidation in cell and skeletal muscle preparations, which is why MOTS-c appears in exercise-mimetic and insulin-sensitivity models alongside more conventional AMPK agonists.

A second line of controlled laboratory investigation concerns its localisation. Under metabolic or oxidative stress the peptide translocates from the cytosol to the nucleus, where it associates with stress-responsive transcription factors including NRF2 and ATF1 and modulates antioxidant response element gene expression. Research models also examine the m.1382A>C polymorphism, which alters the peptide sequence and has been used to study genotype-dependent differences in mitochondrial signalling. Endpoints are typically AMPK phosphorylation state, glucose uptake, mitochondrial respiration rate, and ARE-driven transcript levels. No therapeutic, diagnostic, or clinical conclusion is drawn from any study referenced above, and none should be inferred.