What is MOTS-C?

MOTS-C (mitochondrial open reading frame of the 12S rRNA-c) is a 16-amino-acid peptide encoded within the mitochondrial genome. First identified in 2015, MOTS-C represents a novel class of mitochondrial-derived peptides (MDPs) that act as signalling molecules between mitochondria and the nucleus.

Unlike nuclear-encoded peptides, MOTS-C is translated from mitochondrial DNA within the mitochondrial matrix, then exported to the cytosol and extracellular space. For UK research laboratories, MOTS-C serves as a reference compound for studies examining mitochondrial signalling, metabolic regulation, and cellular stress responses.

MOTS-C operates through several distinct mechanisms in cellular and in vitro models:

Metabolic Regulation — MOTS-C regulates metabolic pathways through activation of AMP-activated protein kinase (AMPK). In cellular studies, the peptide increases AMPK phosphorylation, leading to downstream effects on glucose uptake, fatty acid oxidation, and mitochondrial biogenesis.

Mitochondrial-Nuclear Communication — As a mitochondrial-encoded peptide, MOTS-C represents a retrograde signalling molecule that communicates mitochondrial status to the nucleus. In cellular models, MOTS-C translocates to the nucleus and modulates gene expression programmes related to metabolism and stress resistance.

Cellular Stress Response — MOTS-C is upregulated in response to metabolic stress, including glucose deprivation and oxidative stress. In cellular studies, the peptide confers resistance to metabolic stress by enhancing glucose uptake and optimising mitochondrial function.

Insulin Sensitivity — In cellular and animal models, MOTS-C improves insulin sensitivity through multiple pathways. The peptide enhances glucose uptake in skeletal muscle cells and adipocytes, and reduces hepatic glucose production in hepatocyte cultures.

MOTS-C is employed across multiple research domains in UK laboratories:

Metabolic Disease Research — In vitro studies examine MOTS-C's effects on glucose metabolism, insulin signalling, and lipid oxidation in cellular models.

Ageing and Cellular Senescence — Cellular senescence models examine MOTS-C's effects on senescence markers, telomere maintenance, and stress resistance.

Mitochondrial Biology — MOTS-C serves as a tool compound for studying mitochondrial-nuclear communication and the role of mitochondrial DNA-encoded peptides in cellular regulation.

Exercise Physiology — In cellular models, MOTS-C is studied in the context of exercise-mimetic effects. The peptide activates AMPK and enhances metabolic flexibility, creating research questions about mitochondrial-derived peptides and physical activity.

Comparative Mitochondrial Peptides — MOTS-C is compared to other mitochondrial-derived peptides (humanin, SHLPs) in cellular studies.

MOTS-C is supplied as a lyophilised powder. Standard laboratory preparation:

• Bacteriostatic water (0.9% benzyl alcohol) recommended for reconstitution
• Typical concentrations: 1–10 mg/mL depending on assay requirements
• Solubility: The peptide is generally soluble in aqueous solutions; brief vortexing may aid dissolution
• Protease sensitivity: Due to small size, MOTS-C may be susceptible to proteolytic degradation; protease inhibitors may be included in incubation media
• pH: Maintain solutions at pH 6.5–7.5

• Lyophilised powder: −20°C, protected from light
• Reconstituted solution: 2–8°C, protected from light
• Stability: 7–14 days under refrigeration; aliquot and freeze at −20°C for extended studies
• Avoid: Repeated freeze-thaw cycles