MOTS-c 10mg

MOTS-c (Mitochondrial Open reading frame of the Twelve S rRNA type-c, CAS 1627580-64-6) is a 16-amino acid peptide encoded by a short open reading frame within the mitochondrial 12S rRNA gene (MT-RNR1). It has a molecular formula of C₁₀₁H₁₅₂N₂₈O₂₂S₂ and a molecular weight of 2,174.58 Da. The peptide sequence is MRWQEMGYIFYPRKLR. First characterized by Lee et al. (2015), MOTS-c belongs to the class of mitochondrial-derived peptides (MDPs) — bioactive peptides encoded within the mitochondrial genome that function as retrograde signaling molecules from mitochondria to the nucleus and distant tissues.

The primary characterized signaling target of MOTS-c is the AMP-activated protein kinase (AMPK) pathway. MOTS-c activates AMPK through an indirect mechanism involving modulation of the folate-methionine cycle. Specifically, MOTS-c inhibits the de novo purine biosynthesis pathway by reducing the availability of 10-formyl-tetrahydrofolate (10-formyl-THF), a one-carbon donor required for AICAR (5-aminoimidazole-4-carboxamide ribonucleotide) transformylase activity. This leads to intracellular accumulation of AICAR, an endogenous AMPK activator. AICAR is phosphorylated to ZMP, which mimics AMP and binds the gamma-subunit of AMPK, promoting Thr172 phosphorylation of the catalytic alpha-subunit by upstream kinases (LKB1, CaMKKbeta).

Activated AMPK phosphorylates multiple downstream substrates including acetyl-CoA carboxylase (ACC, Ser79 — inhibiting fatty acid synthesis), ULK1 (Ser555 — activating autophagy), TSC2 (Ser1387 — inhibiting mTORC1), and CRTC2 (promoting cytoplasmic sequestration to suppress gluconeogenic gene transcription). Kim et al. (2018) further demonstrated that MOTS-c undergoes nuclear translocation under metabolic stress conditions, where it interacts with antioxidant response element (ARE) transcription factors to regulate adaptive gene expression.

Supplied as a lyophilized powder for in vitro research applications only. Not for human or veterinary use.

In Vitro Research Applications: MOTS-c is employed in metabolic signaling and mitochondrial biology research. Standard cell models include C2C12 myotubes (skeletal muscle), HepG2 hepatocytes, and 3T3-L1 adipocytes. Key assay formats include AMPK activation assays (phospho-Thr172 AMPK-alpha Western blot), downstream substrate phosphorylation panels (phospho-ACC Ser79, phospho-ULK1 Ser555, phospho-raptor Ser792), and metabolomic profiling of the folate-methionine cycle using LC-MS/MS. Glucose uptake assays using 2-NBDG (fluorescent glucose analog) or radiolabeled 2-deoxyglucose quantify functional metabolic effects. Working concentrations in cell culture typically range from 0.1 to 10 micromolar.

Signaling Pathway Studies: Research applications include AICAR accumulation measurement by HPLC following MOTS-c treatment (establishing the mechanistic link to AMPK activation), nuclear translocation assays by subcellular fractionation and Western blot or immunofluorescence microscopy with anti-MOTS-c antibodies, and chromatin immunoprecipitation (ChIP) assays to characterize MOTS-c interaction with ARE-containing promoter regions. The AMPK-dependence of observed effects is verified using AMPK inhibitors (Compound C/dorsomorphin) or AMPK-alpha knockout cell lines. Mitochondrial function can be assessed in parallel using Seahorse XF respirometry to measure oxygen consumption rate (OCR) and extracellular acidification rate (ECAR).

Molecular Characterization: Identity verification is performed via ESI-MS or MALDI-TOF mass spectrometry (expected MW 2,174.58 Da). Purity is assessed by reversed-phase HPLC. The peptide sequence can be confirmed by tandem MS/MS fragmentation. Stability under cell culture conditions is evaluated by time-course HPLC in complete media at 37 degrees C. Cellular uptake kinetics can be characterized using biotinylated or fluorescently labeled MOTS-c analogs with confocal microscopy and flow cytometry.

References

1. Lee C, et al. (2015) The mitochondrial-derived peptide MOTS-c promotes metabolic homeostasis and reduces obesity and insulin resistance. Cell Metab, 21(3):443-454. PMID: 25738459
2. Kim SJ, et al. (2018) MOTS-c: an equal opportunity insulin sensitizer. J Mol Med, 96(9):869-872. PMID: 30027295
3. Reynolds JC, et al. (2021) MOTS-c is an exercise-induced mitochondrial-encoded regulator of age-dependent physical decline and muscle homeostasis. Nat Commun, 12(1):470. PMID: 33473109