MOTS-c is a 16-amino-acid peptide encoded within a short open reading frame inside the 12S ribosomal RNA (rRNA) gene of mitochondrial DNA (mtDNA). It was first described in a 2015 paper from a research group at the University of Southern California, building on the earlier discovery of humanin, another short signaling peptide encoded in a different region of mtDNA. Most proteins studied in cell biology are encoded in the nuclear genome; MOTS-c is different, originating from the mitochondrion itself, which is why it has drawn interest from researchers studying how mitochondria might signal metabolic status to the rest of the cell, including the nucleus. Published work spans cultured cells, biochemical pathway studies, and rodent models, alongside human genetic association literature on a naturally occurring sequence variant.
| Attribute | Detail |
|---|---|
| Name | MOTS-c (Mitochondrial Open Reading Frame of the 12S rRNA-c) |
| Length | 16 amino acids |
| Genetic origin | Short open reading frame within the mitochondrial 12S rRNA gene (mtDNA), not the nuclear genome |
| Pathway studied | Folate cycle and de novo purine biosynthesis, AMPK activation, nuclear gene regulation under metabolic stress |
| Known variant | m.1382A>C polymorphism producing a K14Q amino acid substitution |
| Model systems used | Cultured myocytes and other cell lines, high-fat-fed and aging mouse models, human genetic cohorts for the K14Q variant |
| Form supplied | Lyophilized powder, research use only |
What is MOTS-c and where in the genome does it come from?
MOTS-c stands for Mitochondrial Open Reading Frame of the 12S rRNA-c, a name that describes its origin directly: the coding sequence sits inside the gene for 12S rRNA, a structural RNA component of the small mitochondrial ribosomal subunit, rather than in a conventional protein-coding gene. Because mtDNA is a closed, tightly packed genome much smaller than nuclear DNA, finding a functional peptide inside what was assumed to be a purely structural RNA gene was notable in itself. At 16 amino acids, MOTS-c is one of a small number of mitochondrial-derived peptides identified to date, a category that also includes humanin and several humanin-like peptides encoded elsewhere in mtDNA.
What did the original discovery study examine?
Lee and colleagues reported that its cellular actions inhibit the folate cycle and the tethered de novo purine biosynthesis pathway, which in turn activates AMP-activated protein kinase (AMPK), a central cellular energy sensor (Lee et al., 2015). Skeletal muscle appeared to be a primary site of action in their cell and tissue experiments. In mouse experiments, MOTS-c administration was associated with changes in glucose tolerance measurements and insulin-resistance markers during aging and high-fat feeding, alongside lower diet-induced weight gain relative to control mice. The authors framed this as evidence that mitochondria can participate in metabolic homeostasis through peptides encoded in their own genome.
What is the folate cycle and AMPK pathway studied with MOTS-c?
The folate cycle is a set of one-carbon metabolic reactions feeding into de novo purine synthesis, the pathway cells use to build new purine nucleotides from simpler precursors. Inhibiting this pathway in cultured cells was linked to a shift in the cellular AMP-to-ATP ratio that AMPK senses, triggering AMPK activation (Lee et al., 2015). Researchers in this field commonly use AICAR, a compound that mimics a purine-synthesis intermediate, as a pharmacological tool to activate AMPK independently and compare its downstream effects against those produced by MOTS-c in the same cell systems. This is cell-based biochemistry describing enzymatic and metabolic flux changes measured in cultured cells and tissue extracts.
What happens when MOTS-c moves to the nucleus under metabolic stress?
A 2018 study from the same research program reported that MOTS-c translocates to the cell nucleus under metabolic stress, such as glucose restriction in cultured cells, and that this movement depends on AMPK activity (Kim et al., 2018). Once in the nucleus, MOTS-c was reported to regulate a broad set of genes, including genes containing antioxidant response elements, and to interact with stress-responsive transcription factors such as NRF2 (nuclear factor erythroid 2-related factor 2). The authors proposed that the mitochondrial and nuclear genomes may have co-evolved factors that regulate each other directly, a concept referred to as mitonuclear communication, a finding about where a peptide localizes and which genes it associates with under defined laboratory stress conditions.
What does the K14Q variant literature show?
A naturally occurring mitochondrial DNA polymorphism, m.1382A>C, produces a single amino acid substitution in MOTS-c, changing a lysine to a glutamine at position 14 (K14Q), largely specific to East Asian populations. A meta-analysis across three large cohorts reported that men, though not women, carrying the variant allele had a higher prevalence of type 2 diabetes, strongest among men in the lowest tertile of physical activity, a pattern the authors described as a gene-by-activity interaction (Zempo et al., 2021). In the same study, high-fat-fed male mice given standard MOTS-c showed measurable changes in body weight and glucose tolerance, while mice given the K14Q variant did not, and parallel cell assays found lower insulin-sensitizing activity for the variant peptide in vitro. A separate human cohort study examined the same polymorphism against skeletal muscle fiber type composition and muscular performance measures, reporting associations between the variant and fiber-type distribution (Kumagai et al., 2022). This line of work uses K14Q as a tool for probing which parts of the MOTS-c sequence its measured effects depend on.
What have rodent studies measured on aging and physical performance?
A 2021 study examined MOTS-c across young, middle-aged and old mice, reporting measurable physical performance differences across all three age groups, including in a cohort where administration began late in the animals' lifespan (Reynolds et al., 2021). The same study reported changes in nuclear gene expression related to metabolism and proteostasis, skeletal muscle metabolic markers, and myoblast responses to metabolic stress in cells derived from the animals. The authors characterized MOTS-c as an exercise-induced, mitochondrial-encoded factor, noting that circulating peptide levels changed with physical activity in their model.
How does MOTS-c relate to other mitochondrial-derived research peptides?
MOTS-c is one of several short peptides encoded within mitochondrial DNA that researchers now study as a category, distinct from the nuclear-encoded proteins carrying out most mitochondrial functions. For a side-by-side look at MOTS-c, NAD+ and SS-31 in overlapping but mechanistically distinct research contexts, see mitochondrial research compounds compared; that comparison is not repeated here. Background on NAD+ as a coenzyme studied in redox and sirtuin research is covered in what is NAD+. A compound-level summary of MOTS-c is maintained on our MOTS-c learn page.
Handling notes
MOTS-c is supplied as a lyophilized powder for research use. As with other short peptides, it should be stored according to the certificate of analysis and reconstituted using standard bench technique and concentration math for the assay at hand; this is bench preparation for laboratory use, not guidance for use in a subject. See peptide half-life explained for background on why cold storage and prompt use after reconstitution matter for a given research timeline. Confirm identity and purity from the lot-specific certificate of analysis before use in any assay. Lot-specific specs for research-grade MOTS-c are posted on our MOTS-c lot page.
Frequently asked questions
Is MOTS-c the same molecule as humanin?
No. Both are short peptides encoded within mitochondrial DNA, which places them in the same general category of mitochondrial-derived peptides, but they come from different regions of the mitochondrial genome, have different sequences, and have been studied in different cellular pathways.
What cell and animal models have been used to study MOTS-c?
Published studies have used cultured myocytes and other cell lines to characterize pathway effects, along with high-fat-fed and aging mouse models to examine glucose handling, body weight, and physical performance measures.
What is the K14Q variant?
K14Q refers to a naturally occurring mitochondrial DNA polymorphism that substitutes one amino acid in the MOTS-c sequence. It is largely specific to East Asian populations and has been studied for its association with type 2 diabetes prevalence and with reduced activity in cell and mouse assays compared with the standard sequence.
Has MOTS-c been studied directly in humans?
Human data in this literature consists mainly of genetic association studies examining the K14Q variant against health measures in existing cohorts. Administration studies measuring direct biological effects have been conducted in cultured cells and in mice, not in human trials.
What outcome measures do these rodent studies report?
Reported measures include glucose tolerance testing, body weight tracking, physical performance testing, markers of insulin sensitivity, and gene expression changes in skeletal muscle and nuclear gene sets.
How is MOTS-c supplied for laboratory use?
As a lyophilized powder intended for research use only, sold by lot with an accompanying certificate of analysis.
References
- 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. 2015;21(3):443-454. PubMed 25738459.
- 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. 2018;28(3):516-524.e7. PubMed 29983246.
- Zempo H, Kim SJ, Fuku N, et al. A pro-diabetogenic mtDNA polymorphism in the mitochondrial-derived peptide, MOTS-c. Aging (Albany NY). 2021;13(2):1692-1717. PubMed 33468709.
- 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. 2021;12(1):470. PubMed 33473109.
- Kumagai H, Natsume T, Kim SJ, et al. The MOTS-c K14Q polymorphism in the mtDNA is associated with muscle fiber composition and muscular performance. Biochim Biophys Acta Gen Subj. 2022;1866(2):130048. PubMed 34728329.
Research use only. Homegrown Peptides products are for laboratory research and are not for human or animal use. Nothing in this article is medical advice.
