Research Overview
MOTS-c, short for Mitochondrial Open Reading Frame of the Twelve S rRNA type-c, is a 16-amino-acid peptide encoded within the mitochondrial 12S ribosomal RNA gene rather than the nuclear genome. The sequence MRWQEMGYIFYPRKLR was first characterised by the Lee laboratory at the University of Southern California, who identified it as one of the founding members of a class of mitochondrial-derived peptides that signal between the mitochondrion and the rest of the cell.
Because it originates from the mitochondrial genome, MOTS-c is studied as a retrograde signalling molecule that informs nuclear gene expression about mitochondrial energetic status. Researchers are drawn to it as a probe for cross-genome communication, AMPK pathway activation, and adaptive responses to metabolic and exercise stress.
The peptide is highly conserved across vertebrates, which has supported its use in murine, primate and human cell-culture work. The 10 mg vial from originlabsresearch.com is supplied as sterile lyophilised powder at 99.2% purity (CAS 1627580-64-6, MW 2174.5 Da), synthesised by solid-phase chemistry and verified by HPLC and mass spectrometry.
Each batch is accompanied by an analytical certificate available on request. The vial is presented for in-vitro and in-vivo laboratory research only and is not intended for human consumption, clinical use or veterinary administration.
Mechanism Studied in Research
MOTS-c is investigated as a regulator of cellular energy sensing that operates upstream of the AMPK-activated protein kinase (AMPK) signalling cascade. In mechanistic studies the peptide has been shown to influence folate-methionine one-carbon metabolism, which leads to accumulation of AICAR, an endogenous AMPK activator (Lee et al., 2015).
Cell Metabolism. Activated AMPK then phosphorylates downstream substrates that increase glucose uptake via GLUT4 translocation, enhance fatty-acid oxidation and inhibit anabolic processes such as protein and lipid synthesis. MOTS-c has also been investigated for its capacity to translocate to the nucleus under metabolic stress, where it interacts with stress-responsive transcription factors including NRF2 and antioxidant-response elements.
This places the peptide in a unique position as both a cytosolic signalling effector and a nuclear-localised transcriptional co-regulator. In skeletal-muscle cultures and rodent exercise models, MOTS-c levels rise acutely with contraction, and administration of synthetic peptide has been studied for its influence on insulin sensitivity, glucose disposal and mitochondrial gene expression.
Researchers have used phosphoproteomics, GLUT4 imaging and Seahorse extracellular flux assays to characterise the downstream metabolic phenotype. The receptor that mediates extracellular MOTS-c uptake has not been definitively identified, and elucidation of the binding interaction remains an active area of investigation. This open mechanistic question is itself a reason researchers continue to use the peptide as a tool compound, as it is one of the few well-characterised peptides whose receptor biology is still being mapped.
Research Applications
Insulin sensitivity and glucose-uptake research. MOTS-c is used in L6 myotube, C2C12 and primary adipocyte cultures to study insulin-stimulated and AMPK-mediated GLUT4 translocation. Investigators combine it with insulin-resistance models induced by palmitate or high-glucose challenge to assess restoration of glucose disposal, often pairing the readout with phospho-AKT and phospho-AMPK western blots.
Mitochondrial bioenergetics and AMPK signaling. In Seahorse extracellular flux assays, MOTS-c is investigated for its effect on basal respiration, ATP-linked oxygen consumption and maximal respiratory capacity. Researchers also study its influence on mitochondrial biogenesis markers such as PGC-1alpha, TFAM and NRF1, and on the AMPK-ACC-CPT1 axis governing fatty-acid oxidation.
Exercise-physiology and skeletal-muscle research. Because circulating MOTS-c rises with acute exercise, it has been used as a probe to investigate muscle-adaptation pathways. Studies in rodent treadmill and resistance models have characterised changes in fibre-type composition, capillary density and AMPK pathway activation following exogenous peptide administration.
Age-related metabolic decline and senescence research. MOTS-c is investigated in aged rodent and senescent cell models for its influence on insulin sensitivity, mitochondrial DNA copy number and SASP-related markers. The peptide’s identity as a mitochondrial-derived signaling molecule positions it as a tool for studying mito-nuclear retrograde communication in the context of metabolic ageing.
Reconstitution Reference
MOTS-c is supplied as a sterile lyophilised powder in a 10 mg vial. Bacteriostatic water (0.9% benzyl alcohol) is the standard diluent for laboratory reconstitution, as the preservative supports multi-draw use across the working period.
Before opening, the vial is equilibrated to room temperature for ten to fifteen minutes to prevent condensation forming on the stopper. The rubber septum is swabbed with 70% isopropanol, then the diluent is injected slowly down the inner wall of the vial rather than directly onto the powder cake. Vigorous shaking is avoided.
The vial is gently swirled or rolled between the palms until the powder dissolves into a clear, colourless solution. A worked example for the 10 mg vial: adding 2 mL of bacteriostatic water gives a working concentration of 5 mg/mL, so 0.02 mL withdrawn into a U-100 insulin syringe corresponds to 100 micrograms of peptide.
Alternatively, 1 mL of diluent yields a 10 mg/mL stock for laboratory-preferred smaller working volumes. The lot number, diluent and reconstitution date are recorded on the vial label and in the laboratory notebook for traceability and audit purposes.
Storage and Handling
Lyophilised MOTS-c is stable for at least twenty-four months when stored sealed at -20°C, protected from light and moisture. For long-term archival storage of bulk research stocks, -80°C is preferred. Once reconstituted with bacteriostatic water, the solution should be kept refrigerated at 2-8°C and used within three to four weeks based on published stability data for similar mitochondria-derived peptides.
Repeated freeze-thaw cycling of the reconstituted solution should be avoided because it can promote aggregation and loss of activity. If extended storage of working solution is required, researchers aliquot into low-protein-binding polypropylene tubes and freeze once at -20°C.
All vials are protected from direct sunlight and fluorescent UV exposure, and warming during handling should be minimized. Any reconstituted material that becomes cloudy, discoloured or shows visible particulate should be discarded and a fresh vial reconstituted.
References
[2] Kim SJ, Xiao J, Wan J, Cohen P, Yen K. (2017). Mitochondrial-derived peptides as novel regulators of metabolism. Nature Reviews Endocrinology.
[3] Kim KH, Son JM, Benayoun BA, Lee C. (2018). The mitochondrial-encoded peptide MOTS-c translocates to the nucleus to regulate nuclear gene expression in response to metabolic stress. Cell Metabolism.
[4] Reynolds JC, Lai RW, Woodhead JST, Joly JH, Mitchell CJ, Cameron-Smith D, Lu R, Cohen P. (2021). MOTS-c is an exercise-induced mitochondrial-encoded regulator of age-dependent physical decline and muscle homeostasis. Nature Communications.
[5] Lu H, Wei Y, Zhu Y, Wang X, Li S, Wang L. (2019). MOTS-c peptide regulates adipose homeostasis and improves metabolic function in experimental models. Frontiers in Endocrinology.