🧬 Aging Wiki

mots-c-peptide

Properties1
aliasesMitochondrial Open Reading Frame of the 12S rRNA-c, mitochondrial-derived peptide MOTS-c, MDP, MOTSC_HUMAN, MOTS c

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MOTS-c (endogenous peptide)

A 16-amino-acid peptide encoded by a short open reading frame embedded within the mitochondrial 12S rRNA gene (MT-RNR1) — making it one of the only biologically active peptides translated from the mitochondrial genome 1. MOTS-c functions as a circulating “mitokine”: it is released from skeletal muscle in response to exercise and metabolic stress, declines in plasma with aging, and promotes insulin sensitivity primarily through AMPK activation via folate-cycle disruption. It is the best-characterised member of the mitochondrial-derived peptide (MDP) class 2.

Companion page: mots-c covers therapeutic delivery framing, preclinical intervention evidence, and clinical-stage assessment for exogenous MOTS-c administration. This page covers the endogenous biology: gene structure, expression regulation, aging trajectory, and population genetics.

Identity

PropertyValue
UniProtA0A0C5B5G6 (MOTSC_HUMAN; Swiss-Prot reviewed)
Parent geneMT-RNR1 (NCBI Gene 4549; HGNC:7470)
Gene typeMitochondrial rRNA gene harbouring a peptide-coding ORF
SequenceMRWQEMGYIFYPRKLR
Length16 amino acids
Molecular weight2,174.6 Da (average; consistent with two Met residues → two sulfur atoms)
Molecular formulaC101H152N28O22S2
PubChem CID146675088 (exogenous form — see compound page)
GenAge IDnull — no HAGR entry for MT-RNR1 or MOTS-c as of 2026-05-09

Identity note on ncbi-gene: 4549: NCBI Gene 4549 is the MT-RNR1 gene entry (the 12S rRNA locus). The MOTS-c peptide is translated from a small ORF within this rRNA transcript; it does not have its own Gene ID. The parent-locus NCBI ID is provided for database cross-linking; queries against it will retrieve the rRNA gene, not a protein record.

Identity note on is-noncoding-rna: false: MT-RNR1 is annotated as an rRNA gene (non-coding by canonical classification), but MOTS-c is a translated peptide. UniProt A0A0C5B5G6 has “evidence at protein level” — it is a real protein product. The rRNA gene is a secondary scaffold; the peptide ORF within it is protein-coding. is-noncoding-rna: false reflects the gene product, not the gene class.

Encoding and biogenesis

MOTS-c belongs to the mitochondrial-derived peptide (MDP) class — small peptides translated from ORFs within mitochondrial transcripts 2. The MT-RNR1 gene encodes the 12S ribosomal RNA, a structural component of the mitoribosome small subunit. A 16-codon ORF within this transcript produces MOTS-c.

Biogenesis is mechanistically unusual. The standard mitochondrial genetic code uses AGA/AGG as stop codons, which would produce tandem start/stop signals within the MOTS-c ORF. UniProt A0A0C5B5G6 documents this explicitly: “usage of the mitochondrial genetic code yields tandem start and stop codons so translation must occur in the cytoplasm.” The mechanism — how an MT-RNR1 transcript exits the mitochondria to be translated on cytosolic ribosomes — is not resolved 1. no-mechanism

MDP class context: At least 8 MDPs have documented bioactivity. MOTS-c and humanin (also MT-RNR1-derived) are the most-studied. SHLP1–6 are encoded within 16S rRNA (MT-RNR2). All known MDPs are <25 amino acids and circulate in plasma. Levels of humanin, MOTS-c, and SHLP2 are reduced in obese and diabetic states 3.

Subcellular localisation and trafficking

CompartmentEvidence
Secreted (plasma)Circulating MOTS-c detected by ELISA; declines with age and metabolic disease 4
MitochondrionSite of primary expression; consistent with MT-RNR1 transcription
NucleusTranslocates from cytoplasm to nucleus under metabolic stress 5

The nuclear translocation mechanism is not characterised. UniProt mutagenesis data indicate positions 11–14 are required for both nuclear localisation and DNA binding; positions 13–16 are required for DNA binding but not for nuclear localisation. MOTS-c has no classical nuclear localisation signal 1. no-mechanism

Mechanism of action

Folate-methionine cycle inhibition → AICAR → AMPK

The primary metabolic mechanism, demonstrated by Lee et al. 2015 1:

  1. MOTS-c enters cells (uptake receptor unknown) and inhibits the folate-methionine cycle in skeletal muscle.
  2. Reduced methylene-tetrahydrofolate availability impairs de novo purine synthesis.
  3. AICAR (5-aminoimidazole-4-carboxamide ribonucleotide) accumulates — a natural AMP analogue and direct AMPK activator.
  4. Elevated AICAR → ampk activation → metabolic reprogramming (GLUT4 translocation, autophagy induction, mTOR suppression, mitochondrial biogenesis).

This AMPK activation route is mechanistically distinct from: (a) AMP/ADP-sensing triggered by exercise-induced energy depletion; (b) complex-I inhibition used by metformin; and (c) direct AICAR supplementation. The folate-cycle input is the distinguishing mechanistic signature of MOTS-c.

Verification caveat: The folate-AICAR step was demonstrated primarily in cell culture (C2C12 myotubes) in Lee 2015. In vivo demonstration of the folate-cycle step (as opposed to alternative AMPK-activating paths) is less direct. needs-replication

Nuclear transcriptional regulation

Under metabolic stress, MOTS-c translocates to the nucleus and regulates transcription of metabolic and proteostatic genes — including those involved in glucose transport (GLUT4), anti-inflammatory signalling (STAT3, IL-10), and stress response 5. This places MOTS-c in a rare category of peptides that are both circulating hormones and intracellular transcription modulators.

Exercise induction and aging trajectory

Exercise-induced expression in humans

MOTS-c is classified as an exerkine — an endogenous factor released by exercise that transduces metabolic benefits to target tissues 5.

Reynolds et al. 2021 (Nat Commun): In n=10 healthy young male volunteers (24.5 ± 3.7 yr), a single bout of aerobic exercise induced an 11.9-fold increase in skeletal muscle MOTS-c expression 5. Plasma MOTS-c also increased. The authors additionally showed that MOTS-c translocates to the nucleus under metabolic stress and regulates gene programmes related to metabolic adaptation and proteostasis maintenance.

Woodhead & Merry 2021 (BBA Gen Subj): Acute high-intensity exercise increases both humanin and MOTS-c in muscle and plasma; MOTS-c treatment produces adaptations overlapping with those of physical activity 6.

Whether MOTS-c is causally responsible for a component of exercise’s aging benefits (versus being a correlated marker) is not established. no-mechanism

The relationship between aging and MOTS-c expression is compartment-dependent:

  • Plasma MOTS-c: Declines with aging and in metabolic disease states (obesity, T2D) across multiple cohort samples [^zheng2023; ^merry2020]. This decline is the basis for the “MOTS-c as aging biomarker” framing.
  • Skeletal muscle MOTS-c: Paradoxically, D’Souza et al. 2020 found muscle MOTS-c mRNA expression was ~1.5-fold higher in older (70–81 yr) and middle-aged (45–55 yr) men compared to young (18–30 yr) participants (n=26 per group; observational cross-sectional; healthy sedentary-to-recreationally-active males free from cardiovascular or metabolic disease; plasma MOTS-c simultaneously declined by ~11–21%) 7. This increase associated with slow-type (type I) myofibre composition, which increases with age. The authors propose that muscle upregulation may represent a compensatory response to age-related metabolic dysfunction, with inadequate secretion into plasma, or that compartment-specific processing differs with age.

This plasma/muscle dissociation is an unresolved mechanistic gap and complicates simple “MOTS-c declines with aging” narratives. contradictory-evidence

Aging and hallmark connections

Mitochondrial dysfunction hallmark

MOTS-c expression originates in the mitochondrial genome. Aging-associated mtDNA mutation accumulation and declining mitochondrial biogenesis (reduced TFAM, reduced PGC-1α activity) impair mitochondrial transcription, plausibly reducing MOTS-c output. MOTS-c levels may therefore serve as a proxy for mitochondrial transcriptional health — declining with the mitochondrial-dysfunction hallmark even before frank mitochondrial dysfunction is measurable via standard assays.

Deregulated nutrient sensing hallmark

MOTS-c activates ampk — the canonical energy sensor that is dysregulated with aging (reduced AMPKα protein, blunted activation under energy stress). Via AMPK, MOTS-c feeds into the deregulated-nutrient-sensing hallmark axis:

  • AMPK suppresses mTORC1 (anti-anabolic / pro-autophagy)
  • AMPK activates ULK1 → disabled-macroautophagy reversal
  • AMPK promotes mitochondrial biogenesis (PGC-1α phosphorylation)
  • AMPK improves insulin sensitivity (GLUT4 translocation)

The folate-AICAR-AMPK mechanism is orthogonal to canonical AMPK activators (metformin via complex I; exercise via AMP/ADP), raising the theoretical possibility of additive effects in combination strategies, though no combination study has been conducted. needs-replication

Longevity genetics: the m.1382A>C polymorphism

A natural mtDNA single-nucleotide variant (m.1382A>C, rs111033358), found in East Asian populations (haplogroup D4b2), encodes a K14Q amino-acid substitution at position 14 of MOTS-c. This K14Q variant shows reduced insulin-sensitising efficacy in vitro and in vivo 8.

Population findings (Zempo 2021, n=27,527):

  • Pooled meta-analysis across three Japanese cohorts (J-MICC, MEC, TMM): C-allele males had significantly higher T2D prevalence (OR 1.34, 95% CI 1.14–1.54; p<0.01); no association in females.
  • The male effect was driven by sedentary men: in J-MICC, C-allele men in the lowest physical-activity tertile had 65% greater T2D prevalence than A-allele counterparts (A-allele 11.2% vs C-allele 18.5%; p=0.014). Higher physical activity negated the difference — a kinesio-genomic interaction.
  • Centenarian analysis (n=736 centenarians vs controls): C-allele frequency 7.7% centenarians vs 7.5% controls — no enrichment. Authors concluded the variant “is unlikely to be involved with exceptional longevity.”

This reverses a prior small-sample report (n=96 centenarians) that had suggested C-allele enrichment. The Zempo 2021 expanded cohort is the authoritative source 8. contradictory-evidence (earlier n=96 claim superseded by n=736+27,527 data)

MR-causal-evidence rationale: The m.1382A>C variant provides an instrument for the MOTS-c K14Q substitution, but formal Mendelian randomization has not been published. Additionally, mtDNA population genetics are subject to selection confounds and LD with other mtDNA variants in haplogroup D4b2, limiting instrument validity. mr-causal-evidence: partial (instrument available; formal MR study pending; mtDNA LD confound unresolved).

Key PTMs and functional residues

No post-translational modifications of endogenous MOTS-c are documented in UniProt A0A0C5B5G6. Mutagenesis studies identify critical regions:

  • Positions 11–14 — required for both nuclear localisation and DNA binding (abolishing these four residues eliminates both activities; UniProt mutagenesis evidence)
  • Positions 13–16 — required for DNA binding but NOT for nuclear localisation (abolishing these four residues abolishes DNA-binding activity while nuclear translocation is preserved; UniProt mutagenesis evidence)
  • Position 14 (Lys → Gln, K14Q) — natural m.1382A>C variant; reduces insulin-sensitising activity in vitro and in vivo 8

unsourced — No systematic PTM mapping of endogenous MOTS-c has been published; the mutagenesis data above comes from recombinant/synthetic peptide experiments.

Limitations and knowledge gaps

  • no-mechanism — Mechanism of cellular uptake of secreted MOTS-c is unknown (no receptor identified).
  • no-mechanism — Nuclear translocation mechanism is uncharacterised; no classical NLS; specific DNA-binding targets not catalogued genome-wide.
  • no-mechanism — How MT-RNR1 transcript exits mitochondria to be translated on cytosolic ribosomes is unresolved (UniProt A0A0C5B5G6 explicitly flags this).
  • needs-replication — Folate-AICAR mechanism demonstrated primarily in cell culture; in vivo confirmation of folate-cycle step needs independent replication.
  • contradictory-evidence — Plasma MOTS-c declines with age, but skeletal muscle MOTS-c mRNA increases ~1.5-fold in older men 7; compartment-specific regulation mechanism unknown.
  • contradictory-evidence — Earlier centenarian-enrichment claim (n=96) superseded by Zempo 2021 null finding (n=736). The claim that m.1382A>C associates with longevity should be treated as falsified in that population.
  • needs-canonical-id — No GenAge/HAGR entry for MT-RNR1 or MOTS-c as of 2026-05-09; no Ensembl ORF-level ID.
  • needs-human-replication — All interventional evidence for exogenous MOTS-c is rodent or in vitro; see mots-c for clinical-stage assessment.

Cross-references

  • mots-c — therapeutic delivery, preclinical intervention evidence, clinical-stage assessment (R36)
  • ampk — primary downstream pathway; MOTS-c → AICAR → AMPK activation
  • mitochondrial-dysfunction — hallmark; MOTS-c expression reflects mtDNA transcriptional capacity
  • deregulated-nutrient-sensing — hallmark; MOTS-c → AMPK → nutrient-sensing normalisation
  • insulin-igf1 — intersecting pathway; MOTS-c improves insulin sensitivity via AMPK
  • disabled-macroautophagy — downstream hallmark; AMPK activation de-represses autophagy (ULK1 phosphorylation)
  • folate-cycle — immediate upstream mechanism (implicit stub — page does not exist yet)
  • tfam — mitochondrial transcription regulator; upstream of MT-RNR1 expression
  • pgc-1alpha — regulates mitochondrial biogenesis; indirectly upstream of MOTS-c output

Implicit stubs created by this page:

  • [[folate-cycle]] — referenced as MOTS-c’s primary mechanism target; no wiki page exists

Footnotes

Footnotes

  1. doi:10.1016/j.cmet.2015.02.009 · Lee C, Zeng J, Drew BG, Sallam T, Martin-Montalvo A, Wan J, Kim SJ, Mehta H, Hevener AL, de Cabo R, Cohen P · Cell Metabolism 2015;21(3):443–454 · in-vivo (mouse) + in-vitro · model: CD-1 mice (HFD) and C57BL/6J mice (aged, 12 months); C2C12 myotubes · Discovery paper: identified 16-aa MOTS-c from MT-RNR1 ORF; demonstrated folate-cycle inhibition → AICAR → AMPK mechanism; prevented diet-induced obesity and reversed age-dependent insulin resistance · local PDF available in a local paper archive (692 citations; impact percentile 100) ↩ ↩2 ↩3 ↩4

  2. doi:10.1172/JCI158449 · Miller B, Kim SJ, Kumagai H, Mehta HH, Xiang W, Liu J, Bar-Shai A, Basisty N, Schilling B, Cohen P · Journal of Clinical Investigation 2022;132(8):e158449 · review · n/a · Comprehensive review of 8 MDPs as metabolic signal transducers; MOTS-c, humanin, SHLP1–6; aging decline and disease associations · local PDF available in a local paper archive (91 citations; fwci 22.4) ↩ ↩2

  3. doi:10.1152/ajpendo.00249.2020 · Merry TL, Chan A, Woodhead JST, Reynolds JC, Kumagai H, Kim SJ, Lee C · American Journal of Physiology–Endocrinology and Metabolism 2020;319(4):E541–E548 · review · n/a · Eight MDPs; circulating MOTS-c, humanin, SHLP2 reduced in obesity/diabetes; exercise induction · PMID 32776825 ↩

  4. doi:10.3389/fendo.2023.1120533 · Zheng Y, Wei Z, Wang T · Frontiers in Endocrinology 2023 · review · n/a · Plasma MOTS-c declines with aging; exercise-mimetic and metabolic protection roles; review of therapeutic potential · PMID 36761202 ↩

  5. doi:10.1038/s41467-020-20790-0 · Reynolds JC, Lai RW, Woodhead JST, Joly JH, Mitchell CJ, Cameron-Smith D, Lu R, Cohen P, Graham NA, Benayoun BA, Merry TL, Lee C · Nature Communications 2021;12(1):470 · in-vivo (mouse) + human observational (exercise) · n=10 (human exercise cohort; healthy young males 24.5 ± 3.7 yr); n=10–19 per group (aged C57BL/6N mice) · 11.9-fold muscle MOTS-c induction in humans post-exercise; nuclear translocation under metabolic stress; late-life treatment (15 mg/kg/day IP 3×/week, ~24 mo C57BL/6N) improved grip strength, gait, walking capacity; lifespan trend ns · local PDF available in a local paper archive ↩ ↩2 ↩3 ↩4

  6. doi:10.1016/j.bbagen.2021.130011 · Woodhead JST, Merry TL · Biochimica et Biophysica Acta – General Subjects 2021 · review · Acute high-intensity exercise increases humanin and MOTS-c in muscle and plasma; MOTS-c treatment recapitulates physical-activity adaptations · PMID 34520826 ↩

  7. doi:10.18632/aging.102944 · D’Souza RF, Woodhead JST, Hedges CP, Zeng N, Wan J, Kumagai H, Lee C, Cohen P, Cameron-Smith D, Mitchell CJ, Merry TL · Aging 2020;12(6):5244–5261 · observational cross-sectional · n=26 per group · healthy males (sedentary to recreationally active; free from cardiovascular or metabolic disease; no medications): young (18–30 yr), middle-aged (45–55 yr), older (70–81 yr, two cohorts) · Skeletal muscle MOTS-c protein ~1.5-fold higher in older and middle-aged vs young; plasma MOTS-c declined with age (~11% middle-aged; ~21% older); muscle increase associated with type-I slow-twitch myofibre composition (MYH7); plasma and muscle MOTS-c dissociated in middle-aged and older groups · PMID 32182209; PDF verified in a local paper archive 2026-05-09 ↩ ↩2

  8. doi:10.18632/aging.202529 · Zempo H, Kim SJ, Fuku N, et al. (27 authors) · Aging 2021;13(2):1692–1703 · observational (3 Japanese cohorts) + functional · n=27,527 total (J-MICC n=11,852, MEC n=3,387, TMM n=12,288) · m.1382A>C K14Q variant: pooled OR 1.34 (95% CI 1.14–1.54) for T2D in males (pooled n=11,244 men); kinesio-genomic interaction: C-allele sedentary men T2D prevalence 18.5% vs A-allele 11.2%, p=0.014 (p<0.05); centenarian cohort n=736 found no enrichment (C-allele 7.7% vs 7.5% controls); earlier n=96 centenarian claim superseded · local PDF verified in a local paper archive ↩ ↩2 ↩3

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