MOTS-c in the research literature: a mitochondrial-encoded peptide and how it is studied

MOTS-c is unusual among research peptides: it is encoded not in the nuclear genome but inside the mitochondrial 12S ribosomal RNA gene, in a short open reading frame that was overlooked until 2015. The decade of work since then is mostly cell-based and mouse-based, and it centres on one enzyme, AMPK. This guide summarises what has been reported, what has not, and the handling points that matter for a 16-residue peptide with two methionines. For laboratory research use only.

What MOTS-c is

MOTS-c stands for “mitochondrial open reading frame of the 12S rRNA type-c”. It is a 16-amino-acid peptide (sequence MRWQEMGYIFYPRKLR) encoded by a short open reading frame within the mitochondrial MT-RNR1 gene, which otherwise codes for the 12S ribosomal RNA. It was identified in 2015 by Changhan Lee and colleagues in Pinchas Cohen’s laboratory at the University of Southern California, and belongs to the small family of mitochondrial-derived peptides that also includes humanin and the SHLPs.

Sequence	Met-Arg-Trp-Gln-Glu-Met-Gly-Tyr-Ile-Phe-Tyr-Pro-Arg-Lys-Leu-Arg (MRWQEMGYIFYPRKLR)
Also known as	Mitochondrial ORF of the 12S rRNA type-c; MOTS-c (human)
CAS number	1627580-64-6
Molecular weight	≈ 2,174.6 g/mol (C101H152N28O22S2)
Encoding gene	MT-RNR1 (mitochondrial 12S rRNA)
Solubility	Water, bacteriostatic water

What the literature has studied

AMPK and the folate–methionine cycle

The founding paper (Lee et al., Cell Metabolism, 2015) reported that MOTS-c inhibits the folate cycle and, downstream, de novo purine biosynthesis, leading to accumulation of the intermediate AICAR and activation of AMP-activated protein kinase (AMPK). In cultured cells this was associated with increased glucose uptake and changes in fatty-acid metabolism; in mice fed a high-fat diet, the peptide was reported to reduce weight gain and improve measures of insulin sensitivity. AMPK activation is the mechanism most subsequent papers build on.

Nuclear translocation under metabolic stress

A 2018 follow-up (Kim et al., Cell Metabolism) reported that under metabolic stress, such as glucose restriction or oxidative stress, MOTS-c moves from the cytoplasm into the nucleus and associates with stress-responsive transcription factors, regulating nuclear gene expression. This is the basis for describing MOTS-c as a “mitonuclear” signalling peptide.

Exercise and ageing models

Reynolds et al. (Nature Communications, 2021) reported that MOTS-c levels in skeletal muscle and plasma rise with exercise in humans, and that giving the peptide to young, middle-aged and old mice improved treadmill performance and altered skeletal-muscle metabolic gene expression. Separate work has reported that circulating MOTS-c declines with age.

A natural sequence variant

A variant in the mitochondrial genome, m.1382A>C, changes residue 14 of MOTS-c from lysine to glutamine (K14Q). It is common in East Asian populations and has been associated in some cohorts with altered risk of type 2 diabetes in men, which is cited as genetic evidence that the peptide is functional in people.

Human data

Human work on MOTS-c itself is observational: measurements of circulating levels in relation to age, exercise and metabolic status. A synthetic analogue (not MOTS-c itself) has been through early-phase clinical testing by a biotechnology company. There are no controlled human efficacy data for the native peptide as a research reagent.

What the literature has not shown

Almost every mechanistic finding comes from cell lines and mice, often from a small number of laboratories connected to the original discovery. The AMPK mechanism is well supported in vitro; its relevance in whole organisms rests mainly on mouse data. Statements about effects in people are extrapolations. A research supplier can confirm identity and purity; it cannot tell you what the peptide does in a person.

How MOTS-c is supplied for research

Quantum Peptides supplies synthetic human MOTS-c as a 10 mg lyophilised powder: MOTS-c peptide, 10 mg. Every lot is tested by an independent US laboratory to a minimum of 99% purity by HPLC, with mass-spectrometry identity, and the lot certificate is linked on the product page. Because the sequence contains two methionine residues, look on the certificate for any note of oxidised species (a +16 Da mass peak per oxidised methionine); a clean certificate shows the expected mass with no significant oxidised peak.

Reconstitution and handling

MOTS-c dissolves readily in sterile or bacteriostatic water. As an example, 10 mg reconstituted with 2 mL gives 5 mg/mL; the peptide calculator works it out for any diluent volume, and the reconstitution guide covers the procedure. The main handling point is oxidation: the two methionines (positions 1 and 6) oxidise readily in solution, which changes the mass and can change activity. Prepare solutions fresh where possible, keep them cold (2–8 °C) and dark, avoid repeated freeze–thaw cycles by dividing into single-use portions, and prefer sterile water for cell-based work (see bacteriostatic water vs sterile water). Store the lyophilised powder at −20 °C, desiccated and protected from light (peptide storage and shelf life).

Frequently asked questions

What does “mitochondrial-derived peptide” mean?

A peptide encoded by the mitochondrial genome rather than the nuclear genome. MOTS-c is encoded within the 12S rRNA gene (MT-RNR1).

What is the CAS number of MOTS-c?

1627580-64-6.

What is the molecular weight of MOTS-c?

Approximately 2,174.6 g/mol for the 16-residue human sequence.

Why is MOTS-c sensitive in solution?

Its two methionine residues oxidise readily, adding 16 Da each and potentially altering activity. Fresh preparation, cold dark storage and single-use portions limit this.

Is MOTS-c an AMPK activator?

In the published cell and mouse work, yes: it activates AMPK indirectly, through inhibition of the folate cycle and purine biosynthesis leading to AICAR accumulation.

Can I buy MOTS-c for human use?

No. Quantum Peptides products are supplied for in-vitro and preclinical laboratory research only, not for human or veterinary use.

References

1. Lee C, Zeng J, Drew BG, et al. The mitochondrial-derived peptide MOTS-c promotes metabolic homeostasis and reduces obesity and insulin resistance. Cell Metabolism. 2015.
2. Kim KH, Son JM, Benayoun BA, Lee C. The mitochondrial-encoded peptide MOTS-c translocates to the nucleus to regulate nuclear gene expression in response to metabolic stress. Cell Metabolism. 2018.
3. Reynolds JC, Lai RW, Woodhead JST, et al. MOTS-c is an exercise-induced mitochondrial-encoded regulator of age-dependent physical decline and muscle homeostasis. Nature Communications. 2021.

Quantum Peptides supplies lyophilised research peptides for in-vitro and preclinical laboratory research only. Products are not for human or veterinary use. This guide summarises published literature and is not guidance on administration of any kind.