MOTS-C

MOTS-C was identified in 2015 as a 16-amino-acid peptide encoded by a small open reading frame within mitochondrial 12S rRNA.¹ Its discovery expanded the emerging field of mitochondrial-derived peptides—short signaling molecules produced from regions of mitochondrial DNA that had not traditionally been viewed as protein coding. The original study connected MOTS-C with metabolic homeostasis in cell and mouse models.¹ In 2018, researchers reported that metabolic stress could drive MOTS-C into the nucleus, where it interacted with transcription-related processes and altered stress-responsive gene expression.² This finding positioned the peptide as a possible messenger between mitochondria and the nuclear genome. Later work examined circulating and skeletal-muscle MOTS-C in relation to exercise and age-associated physical decline.³ These studies broadened interest from cellular metabolism to exercise adaptation and aging biology. MOTS-C’s unusual genetic origin and proposed mitochondria-to-nucleus signaling distinguish it from conventional secreted peptides. Most mechanistic and outcome evidence remains preclinical, however, and the extent of its physiological role in humans is still being defined.

MOTS-C appears to coordinate cellular responses to metabolic stress rather than acting through one confirmed surface receptor. One of its best-studied effects is activation of AMP-activated protein kinase (AMPK), an energy sensor that responds to changes in cellular energy status. In preclinical models, MOTS-C-associated AMPK signaling was linked to increased glucose uptake and altered fatty-acid metabolism.¹ Research has also reported changes in skeletal-muscle glucose handling and exercise-related metabolic adaptation.⁴ MOTS-C may additionally participate in mitochondria-to-nucleus communication. Under metabolic stress, the peptide has been observed to translocate to the nucleus and interact with transcriptional networks involved in cellular adaptation. This suggests that some of its effects may arise through changes in gene expression rather than a single receptor cascade. Animal studies have further examined mitochondrial function, physical performance and age-associated metabolic decline.⁴–⁶ Together, the findings support a multi-pathway model involving AMPK, nutrient metabolism and stress-responsive gene regulation. Its upstream molecular targets and the relevance of these pathways to human outcomes remain active areas of investigation.