MOTS-c (mitochondrial open reading frame of the 12S rRNA type-c) is a 16-residue peptide encoded by a short open reading frame inside the mitochondrial 12S ribosomal RNA gene. It belongs to the small group of mitochondrial-derived peptides and is used in cell-based work on AMPK signalling and on mitochondrial-to-nuclear communication. NuVion supplies MOTS-c as a synthetic peptide and laboratory chemical for in vitro research use only.
Key facts
| Type/class | Synthetic peptide, mitochondrial-derived peptide |
| Amino acid count | 16 |
| Sequence | MRWQEMGYIFYPRKLR (Met-Arg-Trp-Gln-Glu-Met-Gly-Tyr-Ile-Phe-Tyr-Pro-Arg-Lys-Leu-Arg) |
| Molecular formula | C101H152N28O22S2 |
| Molecular weight | 2174.6 g/mol |
| CAS number | 1627580-64-6 |
| Synonyms/other names | Mitochondrial ORF of the 12S rRNA type-c, MT-RNR1-derived peptide |
| Supplied form | Lyophilised powder in a sealed vial |
Structure and chemistry
The MOTS-c open reading frame sits within MT-RNR1, the gene for the mitochondrial 12S rRNA. Read with the standard nuclear genetic code it gives a 16-residue product, and the transcript is polyadenylated and translated on cytoplasmic ribosomes, which is why the peptide is described as mitochondrially encoded but cytoplasmically made. Read with the mitochondrial genetic code the same stretch of sequence would be interrupted by a stop codon, a detail that helped establish the cytoplasmic translation model.
The sequence is basic and amphipathic. Three arginines and one lysine against a single glutamate give a net charge of about +3 at neutral pH, and the central Gly-Tyr-Ile-Phe-Tyr-Pro stretch is hydrophobic. Two methionines (positions 1 and 6) and one tryptophan (position 3) are the residues most prone to oxidation, so mass spectrometry of stored solutions is checked for +16 Da and +32 Da species. A naturally occurring mitochondrial DNA variant, m.1382A>C, changes lysine 14 to glutamine (K14Q), and a Tyr8 to Phe substitution is used as an inactive control in several cell-based assays. Synthetic MOTS-c is made by solid-phase synthesis with a free N-terminus and free C-terminal carboxylate, and it dissolves readily in water or dilute aqueous buffer.
Mechanism of action
MOTS-c has no identified cell-surface receptor. In cultured cells it acts intracellularly, and two connected mechanisms have been described. The first runs through one-carbon metabolism. In HEK293 cells and myoblasts, MOTS-c lowers the level of 5-methyltetrahydrofolate and slows de novo purine synthesis. The purine intermediate AICAR then accumulates, and because AICAR is an AMP mimetic it activates AMP-activated protein kinase (AMPK). Phosphorylation of AMPK at Thr172 is the standard readout, with downstream changes including increased GLUT4 expression and higher glucose uptake in differentiated myotubes and adipocytes, and a shift in flux toward glycolysis.
The second mechanism is nuclear. Under glucose restriction, serum deprivation or oxidative stress, MOTS-c moves from the cytoplasm into the nucleus in an AMPK-dependent way. There it associates with chromatin at regions containing antioxidant response elements (ARE) and co-regulates transcription with NRF2 (NFE2L2). Readouts are NRF2 stress response genes such as HMOX1 and NQO1, measured by qPCR, or ARE-driven luciferase reporters. This nuclear translocation is the basis for describing MOTS-c as a retrograde signal, a peptide of mitochondrial origin that adjusts nuclear gene expression to metabolic state.
In C2C12 and LHCN-M2 myoblast cultures, wild-type MOTS-c increases myotube formation while the Y8F variant does not, and the change is linked to reduced STAT3 transcriptional activity downstream of IL-6 and JAK signalling. In myotube culture the peptide also increases Akt phosphorylation and reduces FOXO1 activity, which lowers transcription of myostatin and other FOXO1 targets. These pathway-level findings sit alongside interest in MOTS-c as a marker, since the endogenous peptide is quantified by immunoassay in cell lysates and conditioned media.
Research applications
MOTS-c sits in the Cellular Ageing category and is used in the following kinds of work.
- AMPK activation assays by western blot for phospho-Thr172 AMPK and phospho-ACC in myoblasts, myotubes, adipocytes or HEK293 cells.
- Glucose uptake assays with 2-deoxyglucose or 2-NBDG in differentiated myotubes, with GLUT4 expression by qPCR or immunoblot.
- One-carbon metabolomics by LC-MS, following 5-methyltetrahydrofolate, S-adenosylmethionine and AICAR after peptide exposure.
- Nuclear translocation imaging by immunofluorescence under glucose restriction or oxidative stress, and chromatin immunoprecipitation at ARE-containing promoters.
- ARE and NRF2 reporter assays and target gene expression (HMOX1, NQO1) in cultured cells.
- Myoblast differentiation assays with fusion index and myosin heavy chain readouts, and mitochondrial respiration measurements by extracellular flux analysis.
Handling in the laboratory
The lyophilised peptide is reconstituted with bacteriostatic water added down the side of the vial and swirled gently, with no vortexing, until the solution is clear. The reconstitution calculator gives the volume for a chosen stock concentration from the vial content. Because of the two methionines and the tryptophan, stock solutions are kept away from light, and dividing the stock into single-use aliquots limits both freeze-thaw cycles and repeated exposure to air. For cell work, the stock is diluted into medium immediately before use.
Unopened vials are kept sealed, dry, away from light and refrigerated as described in the product documentation. Reconstituted solution is refrigerated and used within the period given in that documentation. The compound is characterised by RP-HPLC for purity and by mass spectrometry for identity, and the same two methods are the ones to repeat in-house if a stock has been held for some time, since oxidised species elute earlier on a C18 column and show the expected mass shift.
Testing and supply from NuVion
MOTS-c from NuVion is made by a GMP-audited manufacturer and supplied lyophilised in sealed vials. Most batches are independently tested by Janoshik Analytical for purity by RP-HPLC and identity by mass spectrometry, and the Certificate of Analysis for a tested batch is published on the product page and in the Certificates of Analysis library. Orders are dispatched from within Australia.
Related compounds
Compounds in the same category that are often run alongside MOTS-c include SS-31, a cardiolipin-binding tetrapeptide used in mitochondrial membrane and respiration work, and NAD+, the redox coenzyme and sirtuin substrate.
Frequently asked questions
What is MOTS-c used for in research?
It is used as a tool peptide for AMPK activation, one-carbon metabolism and nuclear stress response signalling in cultured cells. Typical readouts are AMPK phosphorylation, glucose uptake in myotubes, folate and purine intermediates by LC-MS, and NRF2 target gene expression.
How is MOTS-c supplied?
As a lyophilised powder in a sealed vial. Purity is determined by RP-HPLC and identity by mass spectrometry, and a Certificate of Analysis for a tested batch is available on the product page.
Is MOTS-c a therapeutic good in Australia?
No. MOTS-c from NuVion is a laboratory chemical for in vitro research. It is not included in the Australian Register of Therapeutic Goods and has not been assessed by the Therapeutic Goods Administration.
How should MOTS-c be stored?
Keep the sealed vial dry, away from light and refrigerated as set out in the product documentation. After reconstitution, keep the solution refrigerated, aliquot it to limit freeze-thaw cycles and air exposure, and use it within the period stated in the documentation.
Research use only. This product is a laboratory chemical supplied for in vitro research. It is not included in the Australian Register of Therapeutic Goods and has not been assessed by the Therapeutic Goods Administration for quality, safety or efficacy. It is not for human or veterinary use, and nothing on this page is a representation about therapeutic use.
