MOTS-c

MOTS-c was discovered in 2015 by Chang Hee Lee and colleagues at the University of Southern California. Its discovery overturned the established dogma that the mitochondrial genome only encodes for 13 proteins of the respiratory chain — revealing that mitochondria also produce regulatory peptides with systemic metabolic effects.

MOTS-c functions as a retrograde signal from mitochondria to the nucleus and other cells, coordinating metabolic responses to bioenergetic stress. Its plasma levels decline with aging in humans, and are lower in type 2 diabetic patients, suggesting it plays a physiological role in metabolic homeostasis. Exercise increases circulating MOTS-c, and exogenous MOTS-c supplementation produces exercise-like metabolic benefits even in sedentary animals.

// AMPK ACTIVATION

MOTS-c activates AMP-activated protein kinase (AMPK) — the master cellular energy sensor — by modulating the folate cycle in a manner that increases AMP:ATP ratio. AMPK activation drives glucose uptake (via GLUT4 translocation), mitochondrial biogenesis (via PGC-1α), and fatty acid oxidation.

// FOLATE CYCLE & AICAR PRODUCTION

MOTS-c inhibits the folate cycle enzyme MTHFD1L, causing accumulation of AICAR (5-aminoimidazole-4-carboxamide ribonucleotide) — a natural AMPK activator. This is distinct from other AMPK activators and explains MOTS-c's unique metabolic signature.