Mechanism
MOTS-c: What Research Says About the Mitochondrial Peptide
Updated · 7 cited sources · ResearchChem Research Team
Short answer: MOTS-c is a 16-amino-acid peptide encoded by a short open reading frame inside the mitochondrial 12S rRNA gene. Its first description in 2015 named skeletal muscle as its main target tissue. In that work, MOTS-c inhibited the folate cycle and the de novo purine synthesis linked to it, which led to AMPK activation. Later studies reported that under metabolic stress, MOTS-c moves into the cell nucleus and changes nuclear gene expression. In mouse models it has been linked to better insulin sensitivity and physical performance, and in humans its levels rose after exercise. Most of the evidence comes from animal and cell models, and MOTS-c remains a research compound only.
What is MOTS-c?
MOTS-c (mitochondrial open reading frame of the 12S rRNA type-c) was first described in 2015 by Lee and colleagues. They reported a short open reading frame within the mitochondrial 12S rRNA that encodes a 16-amino-acid peptide. They described it as a regulator of insulin sensitivity and metabolic homeostasis, with skeletal muscle as its main target organ [1].
MOTS-c belongs to a small group called mitochondrial-derived peptides. These are short peptides encoded in mitochondrial DNA rather than in the nuclear genome. A 2016 review by the same group placed MOTS-c next to humanin as a mitochondrial-encoded peptide. It described these peptides as signals that may act between cells and across the whole organism, and it noted that MOTS-c targets skeletal muscle and enhances glucose metabolism [2].
How does MOTS-c act on metabolism?
The mechanism proposed in the original study runs through one-carbon metabolism. MOTS-c inhibited the folate cycle and the de novo purine biosynthesis connected to it. This led to activation of AMP-activated protein kinase (AMPK), a central sensor of cellular energy status [1]. AMPK activation is the link most later MOTS-c studies build on.
In the same paper, mice treated with MOTS-c were protected from insulin resistance linked to age and to a high-fat diet, and from diet-induced obesity [1]. These results come from rodent models and describe effects on metabolic markers, not clinical outcomes.
Does MOTS-c signal to the nucleus?
A 2018 study by Kim and colleagues reported that MOTS-c moves into the nucleus in response to metabolic stress, and that this depends on AMPK. Once there, it regulated a broad set of nuclear genes under glucose restriction, including genes with antioxidant response elements. It also interacted with stress-responsive transcription factors, including NRF2 [3].
The authors described this as direct communication from the mitochondrial genome to the nuclear genome. They proposed that the two genomes co-evolved to regulate each other [3]. A later review covering aging and age-related disease repeats this model: MOTS-c is encoded in the 12S rRNA region and moves into the nucleus under stress to regulate genes involved in metabolic dysfunction [7].
What does research show about MOTS-c, exercise and muscle?
Reynolds and colleagues (2021) described MOTS-c as an exercise-induced, mitochondrial-encoded regulator. In mice, MOTS-c treatment improved physical performance in young, middle-aged and old animals. It regulated nuclear genes involved in metabolism and protein homeostasis, and it improved muscle cells' adaptation to metabolic stress. Intermittent treatment started late in life improved physical capacity and healthspan in the mouse model [4].
The same study gave one of the few human data points: exercise raised MOTS-c levels in both skeletal muscle and circulation [4]. This is an observation about the body's own MOTS-c responding to exercise. It is not a test of giving MOTS-c to people.
Cell-culture work points the same way. García-Benlloch and colleagues tested MOTS-c in human (LHCN-M2) and mouse (C2C12) muscle precursor cells. Wild-type MOTS-c increased myotube formation, protected against IL-6-induced loss of nuclear myogenin staining, and blocked IL-6-induced STAT3 transcriptional activity. A Y8F mutant, altered in a putative SH2-binding motif in the YIFY region, did none of these things. The authors proposed that MOTS-c interacts with STAT3 through this motif [5].
What has been reported in metabolic disease models?
MOTS-c has also been studied in a mouse model of gestational diabetes mellitus (GDM), induced with a short-term high-fat diet and low-dose streptozotocin. In that model, MOTS-c treatment during pregnancy was reported to lower blood glucose and improve insulin sensitivity and glucose tolerance. Offspring birth weight and offspring deaths were reduced, and skeletal muscle showed better insulin sensitivity and glucose uptake. The authors also reported that MOTS-c protected pancreatic β-cells from streptozotocin-induced injury [6].
These findings fit the skeletal-muscle and glucose-handling profile from the original work. They come from one induced rodent model, so their relevance to any human condition has not been established.
How does MOTS-c relate to aging?
Aging is a recurring theme in MOTS-c research. The 2015 study included protection against age-related insulin resistance in mice [1], and the 2021 exercise study reported benefits from treatment started late in life in mice [4]. A 2022 review notes that plasma MOTS-c levels decline with age. It surveys reported effects across preclinical models of diabetes, cardiovascular disease, osteoporosis, postmenopausal obesity and Alzheimer's disease [7].
| Study | Model | Main reported finding |
|---|---|---|
| Lee et al., 2015 | Mice; cells | Encoded in 12S rRNA; inhibits folate cycle, activates AMPK; prevented diet- and age-related insulin resistance |
| Kim et al., 2018 | Cells under metabolic stress | AMPK-dependent move into the nucleus; regulates antioxidant-response genes; interacts with NRF2 |
| Reynolds et al., 2021 | Mice; human exercise | Improved physical performance across ages in mice; exercise raised MOTS-c levels in human muscle and circulation |
| García-Benlloch et al., 2022 | LHCN-M2 and C2C12 cells | Increased myotube formation; blocked IL-6-induced STAT3 activity; Y8F mutant inactive |
| Yin et al., 2022 | GDM mouse model | Lowered blood glucose; improved insulin sensitivity and glucose tolerance |
What are the limits of the current evidence?
Most published MOTS-c data come from rodents and cultured cells. The human data in the cited abstracts measure the body's own MOTS-c, for example the rise after exercise [4] and the decline with age [7]. They do not come from controlled trials of the peptide. The mechanisms (folate-cycle inhibition, AMPK activation, nuclear translocation and STAT3 interaction) are each supported by a small number of studies, several of them from the same research group.
For researchers sourcing MOTS-c, the findings above describe the native 16-amino-acid sequence studied in these papers. Results from modified or mutant sequences, such as the inactive Y8F variant [5], show that single-residue changes can remove activity in vitro. MOTS-c is sold for laboratory research use only. Nothing here is guidance on dosing or human use.
Frequently asked questions
What does MOTS-c stand for?
Mitochondrial open reading frame of the 12S rRNA type-c. It is a 16-amino-acid peptide encoded in the mitochondrial 12S rRNA gene.
What is the main proposed mechanism of MOTS-c?
The original research reported that MOTS-c inhibits the folate cycle and linked de novo purine synthesis, leading to AMPK activation, mainly in skeletal muscle.
Does MOTS-c act in the nucleus?
A 2018 study reported that MOTS-c moves into the nucleus under metabolic stress in an AMPK-dependent way. There it regulates nuclear genes, including antioxidant-response genes, and interacts with NRF2.
Is there human data on MOTS-c?
Published abstracts report that exercise raised MOTS-c levels in human muscle and circulation, and reviews note that plasma levels fall with age. Effects of giving the peptide come from animal and cell studies.
How is MOTS-c related to exercise research?
A 2021 study called MOTS-c an exercise-induced regulator. It reported improved physical performance in mice of several ages, including with treatment started late in life.
Is MOTS-c approved for human use?
No. MOTS-c is sold as a research-use-only compound, and the cited evidence is preclinical apart from measurements of its natural levels.
Cited studies
- Lee C, Zeng J, Drew BG, et al. The mitochondrial-derived peptide MOTS-c promotes metabolic homeostasis and reduces obesity and insulin resistance.. Cell Metab. 21(3):443-54 (2015). PubMed 25738459 DOI
- Lee C, Kim KH, Cohen P. MOTS-c: A novel mitochondrial-derived peptide regulating muscle and fat metabolism.. Free Radic Biol Med. 100:182-187 (2016). PubMed 27216708 DOI
- 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 Metab. 28(3):516-524.e7 (2018). PubMed 29983246 DOI
- 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.. Nat Commun. 12(1):470 (2021). PubMed 33473109 DOI
- García-Benlloch S, Revert-Ros F, Blesa JR, Alis R. MOTS-c promotes muscle differentiation in vitro.. Peptides. 155:170840 (2022). PubMed 35842023 DOI
- Yin Y, Pan Y, He J, et al. The mitochondrial-derived peptide MOTS-c relieves hyperglycemia and insulin resistance in gestational diabetes mellitus.. Pharmacol Res. 175:105987 (2022). PubMed 34798268 DOI
- Mohtashami Z, Singh MK, Salimiaghdam N, et al. MOTS-c, the Most Recent Mitochondrial Derived Peptide in Human Aging and Age-Related Diseases.. Int J Mol Sci. 23(19) (2022). PubMed 36233287 DOI
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