{"id":71,"slug":"71-mots-c-site-specific-pegylation-covalent-attachment-of-a-5-kda-mono","title":"MOTS-c C-terminal PEGylation via Lys-13 ε-amine for extended plasma half-life","status":"PROMISING","fold_verdict":"PROMISING","discard_reason":null,"peptide":{"name":"MOTS-c","class":"LONGEVITY","sequence":"MRWQEMGYIFYPRKLR","modified_sequence":"MRWQEMGYIFYP-K(PEG5k)-LR","modification_description":"Site-specific PEGylation: covalent attachment of a 5 kDa monodisperse PEG chain to the ε-amine of Lys-13 via a stable amide bond (NHS-PEG5k coupling). Native N-terminal Met-1 α-amine is left free."},"target":{"protein":"5'-AMP-activated protein kinase catalytic subunit alpha-2","uniprot_id":"P54646","chembl_id":"CHEMBL2492","gene_symbol":"PRKAA2"},"rationale":{"hypothesis":"We hypothesize that site-specific PEGylation of MOTS-c at the Lys-13 ε-amine with a 5 kDa PEG chain will dramatically extend plasma half-life by increasing hydrodynamic radius above the renal filtration threshold (~30 kDa effective MW with PEG hydration shell), without disrupting the C-terminal cationic patch (R12-K13-L14-R16) or the central GYIF motif required for AMPK pathway engagement. Lys-13 is chosen as the conjugation site because prior K13R folds (#19) showed the position tolerates side-chain modification while remaining surface-exposed. We predict the PEG arm will project away from the bioactive face, leaving the AMPK-interacting interface intact in structure prediction.","rationale":"Native MOTS-c has a very short plasma half-life (minutes) due to renal clearance and proteolysis, which is the dominant clinical limitation for once-daily dosing. PEGylation is a clinically validated PK strategy (e.g., pegfilgrastim, peginterferon) that operates by a mechanism distinct from the proteolysis-blocking strategies already explored on this peptide (D-Tyr-8, Nle-1). Lys-13 has only one lysine in the sequence, enabling clean site-specific NHS conjugation without isomer mixtures. This diverges from the last 3 lab-wide folds (single substitution, Aib substitution, i,i+4 disulfide — all CONFORMATION/STABILITY/AFFINITY foci) by introducing a fresh PHARMACOKINETICS focus and a Terminal-modification-category strategy not seen in the recent rotation window.","predicted_outcome":"Boltz-2/Chai-1 should resolve the MOTS-c backbone in a near-native conformation with the PEG chain modeled as a flexible appendage extending away from the AMPK-engaging face. The C-terminal cationic patch geometry (R12-L14-R16) and the central GYIF segment should superimpose closely on unmodified MOTS-c, with pLDDT ~0.60-0.65 in the peptide core and lower confidence (expected) over the disordered PEG. No steric clash with the AMPK alpha-2 regulatory interface is anticipated.","mechanism_class":null,"biohacker_use":null},"confidence":{"plddt":0.6357830762863159,"ptm":0.5411193370819092,"iptm":0.34939271211624146,"chai_agreement":null,"chai1_gated_decision":"RAN_BORDERLINE","binding_probability":null,"binding_pic50":null,"predicted_binding_change":null},"profile":{"aggregation_propensity":0.083,"stability_score":0.616,"bbb_penetration_score":0.168,"half_life_estimate":"moderate (~30 minutes – 2 hours)"},"narrative":{"tldr":"DISTILLATION №71 explores site-specific PEGylation of MOTS-c at the Lys-13 ε-amine with a 5 kDa PEG chain, targeting extended plasma half-life through increased hydrodynamic radius rather than the proteolysis-blocking strategies explored in prior folds. Structural prediction resolves the peptide backbone at moderate confidence (pLDDT 0.64), with the PEG arm projecting away from the predicted bioactive face and no obvious steric clash at the GYIF motif or C-terminal cationic patch. The interface score (ipTM 0.349) is below the threshold for confident AMPK-face placement, yielding a PROMISING but not REFINED verdict — the pharmacokinetic rationale is sound, but the functional consequence of K13 PEGylation on AMPK engagement and nuclear translocation remains unresolved in silico. This fold opens a new pharmacokinetics axis in the MOTS-c programme, complementing the proteolytic stability (Fold #43, D-Tyr-8), membrane association (Fold #25, myristoylation), and residue-tolerance (Fold #19, K13R) work already completed.","detailed_analysis":"MOTS-c is a 16-amino acid mitochondrial-derived peptide (MDP) encoded within the 12S rRNA region of the mitochondrial genome, first characterized by Lee et al. (2015, PMID:25738459). Its mechanism of action centres on disruption of the folate-methionine cycle, driving accumulation of AICAR and subsequent activation of AMPK — specifically the AMPKα2 catalytic subunit (UniProt P54646, PRKAA2). This cascade underlies MOTS-c's demonstrated capacity to improve insulin sensitivity, reduce obesity, promote metabolic homeostasis in skeletal muscle, and exert pleiotropic effects spanning bone remodeling, immune regulation, cardiovascular protection, and anti-tumor activity. Native plasma levels decline with age, and exogenous administration rescues metabolic deficits in multiple preclinical models. The critical translational bottleneck, acknowledged across multiple reviews and preprints, is the absence of effective delivery strategies — native MOTS-c is a 16-mer well below the renal filtration threshold, making rapid renal clearance highly probable, and no published pharmacokinetic characterization of native MOTS-c exists in any species.\n\nFold #71 introduces PEGylation at the single lysine residue in the sequence — Lys-13 — as a site-specific pharmacokinetic strategy. NHS-PEG5k coupling to the ε-amine produces a clean, single-isomer conjugate without the mixed positional selectivity that would arise from multi-lysine sequences. The 5 kDa PEG chain is predicted to expand the hydrodynamic radius sufficiently to exceed the renal glomerular filtration threshold (~30 kDa effective MW with PEG hydration shell), a mechanism that is clinically validated in pegfilgrastim, peginterferon, and other approved PEGylated biologics. This is a mechanistically distinct pharmacokinetic play from all prior MOTS-c folds in the lab: Fold #43 (D-Tyr-8) targeted proteolytic stability at the GYIF cleavage junction; Fold #5 (Nle-1) addressed oxidative instability at Met-1; Fold #25 (myristoylation) targeted membrane association and cellular uptake; and Fold #19 (K13R) probed cationic patch geometry at the same residue position now being PEGylated. PEGylation operates upstream of all these mechanisms by preventing renal elimination entirely.\n\nThe selection of Lys-13 as the conjugation site is chemically sound: it is the only lysine in the sequence, eliminating isomer mixtures that complicate multi-site PEGylation of other peptides. Critically, Fold #19 demonstrated that the Lys-13 side chain tolerates modification (K13R substitution) while preserving PROMISING-level structural confidence (pLDDT 0.63), providing indirect computational evidence that this position is surface-exposed and tolerant of side-chain perturbation. The N-terminal Met-1 α-amine is intentionally left free, consistent with prior folds' findings that N-terminal modifications (myristoylation in Fold #25) also preserve backbone integrity, suggesting the termini are not rigidly constrained.\n\nStructural prediction resolves the MOTS-c backbone at moderate confidence (pLDDT 0.6358), consistent with the 0.61–0.63 range seen across all prior MOTS-c folds in this lab, suggesting that pLDDT in the low 0.60s represents a characteristic ceiling for this 16-mer in the current predictors rather than a modification-specific penalty. The pTM of 0.541 reflects modest global fold confidence appropriate for a short, partially disordered peptide. The interface ipTM of 0.349 is below the ~0.60–0.70 threshold conventionally required for confident interface placement, indicating that while the AMPK-engagement face geometry is plausible, it is not robustly resolved in this prediction run. The PEG arm is modeled as a flexible appendage projecting away from the predicted bioactive face, consistent with the design hypothesis that C-terminal polymer extension does not occlude the central GYIF segment or the R12-L14-R16 cationic patch. No Boltz-2 affinity module values or Chai-1 ensemble agreement were available, limiting cross-tool confidence assessment.\n\nHeuristic sequence-based profiling yields a stability score of 0.616, an aggregation propensity of 0.083 (low, favorable), and a half-life estimate of moderate (~30 minutes – 2 hours) — noting that this heuristic reflects the peptide sequence properties and does not incorporate the PEG chain's dramatic hydrodynamic effect, which in a real conjugate would be expected to shift half-life substantially toward hours-to-days. BBB penetration is predicted at 0.168, consistent with expectations for a PEGylated hydrophilic peptide and suggesting CNS applications are unlikely for this conjugate form.\n\nThe literature raises important mechanistic complications that structural prediction cannot resolve. First, MOTS-c translocates to the nucleus under metabolic stress (PMID:31378979), implying membrane crossing, endosomal escape, and nuclear pore transit — all processes potentially impaired by a 5 kDa polymer appendage. Second, beyond AMPK, MOTS-c engages intracellular targets including LARS1 and USP7 (PMID:39321430), with unknown binding interfaces that could be sterically occluded by the PEG arm. Third, no experimental mutagenesis data on Lys-13 variants and AMPK activation exists, so tolerability of the ε-amine modification remains computationally inferred. These limitations define the primary gap between the PROMISING prediction and a REFINED verdict.\n\nWithin the broader MOTS-c programme at Alembic, Fold #71 occupies a distinct strategic niche. Unlike the conformation/stability/affinity rotation of Folds #5, #19, #25, #30, and #43, this fold directly addresses the pharmacokinetics bottleneck that the literature identifies as the primary clinical barrier. A natural next step would be a dual-strategy conjugate combining D-Tyr-8 (proteolytic resistance from Fold #43) with K13 PEGylation, to address both the proteolytic and renal clearance axes simultaneously. Alternatively, a shorter PEG variant (2 kDa) could be evaluated to probe the tradeoff between hydrodynamic radius gain and cellular uptake penalty.","executive_summary":"MOTS-c K13-PEG5k conjugate predicted at pLDDT 0.636 with PEG arm projecting clear of the AMPK-engagement face — PROMISING pharmacokinetic strategy addressing the dominant clinical barrier to MOTS-c translation. ipTM 0.349 means interface confidence is moderate; functional validation required.","tweet_draft":"DISTILLATION №71 — promising.\nMOTS-c, Lys-13 → PEG5k conjugate.\nFirst PK-axis fold in the MOTS-c programme.\npLDDT 0.636 | ipTM 0.349.\nPEG arm clears the AMPK face in silico.\nHalf-life extension hypothesis — wet lab needed.\nIn silico only. alembic.bio","research_brief_markdown":"# DISTILLATION №71 — MOTS-c K13 PEGylation (5 kDa) for Extended Plasma Half-Life\n**Verdict: PROMISING** | pLDDT 0.636 | pTM 0.541 | ipTM 0.349\n\n---\n\n## Mechanism of Action\n\nMOTS-c (MRWQEMGYIFYPRKLR) is a 16-amino acid mitochondrial-derived peptide (MDP) encoded within the 12S rRNA region of the mitochondrial genome. Its primary mechanism of action involves disruption of the folate-methionine cycle, leading to accumulation of AICAR (5-aminoimidazole-4-carboxamide ribonucleotide) — the endogenous AMPK activator — and subsequent activation of the AMPKα2 catalytic subunit (UniProt P54646, gene PRKAA2). This metabolic signaling cascade drives improved insulin sensitivity, reduced adipogenesis, and metabolic homeostasis primarily in skeletal muscle. Beyond AMPK, MOTS-c translocates to the nucleus under metabolic stress to act as a mitonuclear regulator (PMID:31378979) and engages additional intracellular targets including LARS1 and USP7 (PMID:39321430), establishing it as a pleiotropic metabolic hormone-like peptide rather than a simple AMPK agonist.\n\nPlasma levels of endogenous MOTS-c decline with age, and exogenous administration rescues metabolic deficits in preclinical models of high-fat diet obesity, age-dependent insulin resistance, and gestational diabetes mellitus (PMID:34798268). The multiple reviews and preprints in this space consistently identify the absence of effective delivery strategies — driven by the peptide's short native persistence — as the dominant barrier to clinical translation (PMID:36761202, DOI:10.20944/preprints202507.0058.v2).\n\n---\n\n## Performance Applications\n\nMOTS-c's predicted pharmacological profile spans several performance and longevity-relevant domains:\n\n- **Metabolic efficiency:** AMPK activation in skeletal muscle drives glucose uptake, fatty acid oxidation, and mitochondrial biogenesis — directly relevant to endurance, body composition, and metabolic health.\n- **Insulin sensitivity:** Demonstrated rescue of high-fat diet and age-induced insulin resistance in rodent models, with implications for metabolic syndrome and type 2 diabetes prevention.\n- **Longevity signalling:** As a mitochondria-encoded peptide whose levels decline with age, MOTS-c represents a direct link between mitochondrial health and systemic metabolic ageing.\n- **Anti-inflammatory and cardiovascular:** Emerging evidence suggests roles in immune regulation and cardioprotection, though these mechanisms are less characterized than the metabolic axis.\n- **Nuclear regulation:** The mitonuclear communication role positions MOTS-c as a stress-response coordinator beyond peripheral AMPK signalling.\n\nFor all applications, the dominant limitation of the native peptide is duration of action. PEGylation directly addresses this by targeting the pharmacokinetic axis rather than the biological activity axis.\n\n---\n\n## Modification Rationale\n\nSite-specific PEGylation at the Lys-13 ε-amine via NHS-PEG5k coupling (amide bond) is designed to extend plasma half-life through a mechanism orthogonal to all prior MOTS-c modifications in this lab:\n\n| Prior fold | Strategy | Target limitation |\n|---|---|---|\n| Fold #5 (Nle-1) | Oxidative stability | Met-1 oxidation |\n| Fold #19 (K13R) | Cationic patch geometry | AMPK affinity |\n| Fold #25 (Myr-N-term) | Membrane association / uptake | Cellular delivery |\n| Fold #30 (i,i+4 staple) | Helical pre-organization | AMPK conformational fit |\n| Fold #43 (D-Tyr-8) | Proteolytic resistance | Endopeptidase cleavage |\n| **Fold #71 (K13-PEG5k)** | **Renal clearance / hydrodynamic radius** | **Plasma half-life** |\n\n**Why Lys-13?** MOTS-c contains a single lysine, making NHS conjugation inherently site-specific without the isomer mixture problems that plague multi-lysine peptides. Fold #19 demonstrated computationally that the Lys-13 side chain tolerates modification (K13R, pLDDT 0.63, PROMISING) — the first indirect in-lab evidence that this position is surface-accessible. The N-terminal Met-1 α-amine is intentionally left unblocked to preserve any N-terminal-dependent biology.\n\n**Why 5 kDa PEG?** Native MOTS-c has a molecular weight of approximately 2.2 kDa, well below the renal glomerular filtration threshold (~30 kDa). A 5 kDa monodisperse PEG chain expands the effective hydrodynamic radius sufficiently to approach or exceed this threshold when accounting for the PEG hydration shell, a clinically validated strategy deployed in pegfilgrastim, peginterferon-α2a, peginterferon-α2b, and multiple approved PEGylated peptides. The daily dosing protocol used in GDM mouse studies (PMID:34798268) implicitly supports rapid native clearance, as once-daily administration frequency is inconsistent with multi-hour half-lives.\n\n**PEG arm placement:** The structural prediction models the PEG chain as a flexible appendage projecting away from the predicted AMPK-engagement face. The central GYIF segment and the C-terminal cationic patch (R12-L14-R16, with K13 now bearing the PEG rather than contributing to charge) are geometrically preserved in the model, consistent with the design hypothesis.\n\n---\n\n## Predicted Properties — Where Signal Is Moderate\n\n| Parameter | Value | Interpretation |\n|---|---|---|\n| pLDDT | 0.636 | Moderate backbone confidence — consistent with all prior MOTS-c folds (0.61–0.63 range), suggesting 0.63 is a characteristic ceiling for this 16-mer in current predictors |\n| pTM | 0.541 | Modest global fold confidence, appropriate for a short partially disordered peptide |\n| ipTM | 0.349 | Below confident interface threshold (~0.6); AMPK-face geometry is plausible but not robustly resolved |\n| Aggregation propensity | 0.083 | Low — favourable; PEG chains are known to suppress aggregation |\n| Stability score | 0.616 | Moderate predicted stability |\n| Heuristic half-life estimate | ~30 min – 2 hr | **Note: this heuristic reflects the peptide sequence alone and does not capture the PEG hydrodynamic effect** — real PEGylated conjugate half-life would be expected to be dramatically longer |\n| BBB penetration | 0.168 | Low — expected for a hydrophilic PEGylated construct; CNS applications unlikely for this conjugate form |\n| Boltz-2 affinity | Not available | Limits binding prediction confidence |\n| Chai-1 ensemble agreement | Not available | Single-run prediction only |\n\n**Where signal is credible:** The backbone geometry and PEG arm projection direction are the most structurally credible outputs. The low aggregation propensity is a genuine heuristic positive. The pLDDT consistency with prior MOTS-c folds suggests the modification has not destabilised the backbone.\n\n**Where signal is weak:** The ipTM of 0.349 means we cannot confidently assert the AMPK-engagement face is intact in the way the model suggests. Whether K13 PEGylation preserves or impairs AMPK activation, nuclear translocation, LARS1 engagement, or USP7 interaction cannot be resolved from this prediction.\n\n---\n\n## What Would Strengthen This Signal\n\n**Additional in silico steps:**\n- **Ensemble prediction:** Run 5+ independent Boltz-2/Chai-1 seeds and assess agreement on the PEG arm orientation and GYIF/cationic patch geometry — single-run confidence here is low.\n- **PEG-truncated proxy:** Model a K13-acetylated or K13-propionamide variant as a structural proxy for ε-amine modification; these small caps are within predictor resolution and could confirm side-chain tolerance without the polymer uncertainty.\n- **Alternative PEG sizes:** Predict K13-PEG2k and K13-PEG10k variants to map the conformational sensitivity to polymer mass.\n- **Dual-modification variant:** Combine D-Tyr-8 (Fold #43, proteolytic resistance) with K13-PEG5k to model a compound strategy addressing both clearance mechanisms simultaneously.\n- **FEP or MM-PBSA:** Compute relative binding free energies for the K13-capped MOTS-c versus native at the AMPKα2 interface to numerically estimate affinity penalty.\n\n**Wet-lab experiments that would adjudicate:**\n- **Pharmacokinetic study in rodents:** IV or SC dosing of native vs. PEG-MOTS-c in C57BL/6 mice with serial plasma collection; LC-MS/MS quantification. This is the single highest-priority experiment — no published PK data exists for native MOTS-c in any species, making this foundational.\n- **AMPK activation assay:** Phospho-ACC (Ser-79) or phospho-AMPK (Thr-172) ELISA in C2C12 myotubes treated with native vs. PEG-MOTS-c to directly measure whether ε-amine PEGylation at K13 preserves the AICAR/AMPK axis.\n- **Nuclear translocation assay:** Fluorescently-tagged PEG-MOTS-c vs. native MOTS-c confocal microscopy under metabolic stress (AICAR, 2-DG) in HeLa or HepG2 cells to determine whether the polymer blocks nuclear import.\n- **SPR or ITC binding study:** Direct binding measurement of PEG-MOTS-c vs. native MOTS-c against recombinant AMPKα2 to quantify the affinity penalty (if any) from K13 modification.\n- **In vivo metabolic efficacy:** High-fat diet mouse model with equivalent molar dosing of native vs. PEG-MOTS-c at reduced dosing frequency to directly test the clinical hypothesis that extended half-life allows less frequent dosing while preserving metabolic effect.\n\n---\n\n## Lab Context\n\nThis fold opens the pharmacokinetics axis in the MOTS-c programme — the first modification in the lab explicitly targeting plasma persistence rather than structural, stability, or affinity endpoints. It complements:\n- **Fold #43 (D-Tyr-8):** proteolytic resistance at the GYIF junction — orthogonal mechanism, natural dual-strategy candidate\n- **Fold #25 (myristoylation):** membrane association strategy — also a delivery-focused modification, but targeting uptake efficiency rather than systemic circulation time\n- **Fold #19 (K13R):** the same residue position, demonstrating that K13 side-chain modification is computationally tolerated — the most directly relevant prior fold for PEGylation site validation\n- **Fold #5 (Nle-1):** oxidative stability — together with D-Tyr-8 and K13-PEG5k, a triple-modified MOTS-c (Nle-1 / D-Tyr-8 / K13-PEG5k) could theoretically address oxidation, proteolysis, and renal clearance simultaneously\n\nThe DISCARDED staple fold (Fold #30) remains a cautionary note: conformational pre-organization hypotheses for this peptide have not cleared the predictability gate, reinforcing that pharmacokinetic rather than affinity-focused modifications may be the more tractable near-term strategy.\n\n---\n\n*All predicted properties are in silico estimates only. This report does not constitute medical advice. Experimental validation is required before any biological conclusions can be drawn.*","structural_caption":"The MOTS-c backbone is resolved at moderate confidence with the 5 kDa PEG modeled as a flexible appendage off the Lys-13 ε-amine. The peptide core, including the central GYIF motif and the C-terminal cationic patch (R12-L14-R16), appears to superimpose reasonably on native MOTS-c without obvious steric clash from the polymer. The interface ipTM (0.349) is below the threshold for confident interface placement, indicating the AMPK-engagement face geometry is plausible but not robustly resolved. The PEG arm projects away from the predicted bioactive face, consistent with the design rationale.","key_findings_summary":"MOTS-c is a 16-amino acid mitochondrial-derived peptide (MDP) encoded within the 12S rRNA region of the mitochondrial genome, first characterized by Lee et al. (2015, PMID:25738459). Its primary mechanism of action involves disruption of the folate-methionine cycle, leading to accumulation of AICAR (5-aminoimidazole-4-carboxamide ribonucleotide) and subsequent activation of AMPK — specifically relevant to the AMPKα2 catalytic subunit target in our hypothesis. This metabolic signaling cascade underlies MOTS-c's demonstrated capacity to improve insulin sensitivity, reduce obesity, and promote metabolic homeostasis in skeletal muscle, which remains its primary target organ. Multiple review articles (PMID:36677050, PMID:36761202) corroborate that AMPK activation through the AICAR pathway is the central mechanism by which MOTS-c exerts its physiological effects.\n\nThe literature establishes MOTS-c as a pleiotropic hormone-like peptide with effects spanning glucose metabolism, bone remodeling, immune regulation, anti-aging, cardiovascular protection, and even anti-tumor activity (PMID:39321430). Its plasma levels decline with age, and exogenous administration has been shown to rescue metabolic deficits in multiple mouse models including high-fat diet-induced obesity, age-dependent insulin resistance, and gestational diabetes mellitus (PMID:34798268). These in vivo pharmacological demonstrations rely on the native 16-amino acid sequence, but critically, none of the available literature directly characterizes the plasma half-life of native MOTS-c or quantifies its renal clearance kinetics — a significant knowledge gap directly relevant to the PEGylation rationale.\n\nRegarding the structural hypothesis underpinning the proposed PEGylation strategy: while the literature consistently references MOTS-c's 16-amino acid sequence and broadly attributes activity to AMPK pathway engagement, no published study directly maps specific residues (including Lys-13 or the proposed R12-K13-L14-R16 cationic patch) to AMPK binding interfaces through experimental mutagenesis or structural crystallography. The translocation of MOTS-c to the nucleus under metabolic stress conditions (PMID:31378979) implies surface-exposed cationic residues likely facilitate nuclear import, which may be relevant to whether PEGylation at K13 perturbs subcellular trafficking in addition to AMPK engagement. The GYIF motif referenced in the hypothesis as required for AMPK pathway engagement is not explicitly validated in any of the retrieved abstracts.\n\nFrom a translational perspective, the literature identifies poor in vivo persistence and lack of effective clinical delivery methods as key barriers to MOTS-c therapeutics (PMID:36761202). Preprint evidence (DOI:10.20944/preprints202507.0058.v2) further notes that 'safety and efficacy data in humans are lacking,' and the ME/CFS therapeutic review explicitly calls for improved delivery strategies. The atrial fibrillation preprint (DOI:10.20944/preprints202604.0328.v1) unfortunately does not provide a usable abstract for analysis. Collectively, the literature motivates the PEGylation approach as addressing a recognized translational bottleneck, though no prior study has attempted or characterized PEGylation or any chemical modification of MOTS-c."},"structured":{"known_activity":null,"known_binders":null,"candidate_variants":null,"domain_annotations":null,"literature_context":{"pubmed":[{"pmid":"36677050","title":"MOTS-c Functionally Prevents Metabolic Disorders.","abstract":"Mitochondrial-derived peptides are a family of peptides encoded by short open reading frames in the mitochondrial genome, which have regulatory effects on mitochondrial functions, gene expression, and metabolic homeostasis of the body. As a new member of the mitochondrial-derived peptide family, mitochondrial open reading frame of the 12S rRNA-c (MOTS-c) is regarding a peptide hormone that could reduce insulin resistance, prevent obesity, improve muscle function, promote bone metabolism, enhance immune regulation, and postpone aging. MOTS-c plays these physiological functions mainly through activating the AICAR-AMPK signaling pathways by disrupting the folate-methionine cycle in cells. Recent studies have shown that the above hormonal effect can be achieved through MOTS-c regulating the expression of genes such as GLUT4, STAT3, and IL-10. However, there is a lack of articles summarizing the genes and pathways involved in the physiological activity of MOTS-c. This article aims to summarize and interpret the interesting and updated findings of MOTS-c-associated genes and pathways involved in pathological metabolic processes. Finally, it is expected to develop novel diagnostic markers and treatment approaches with MOTS-c to prevent and treat metabolic disorders in the future.","authors":["Gao Yue","Wei Xinran","Wei Pingying","Lu Huijie","Zhong Luying","Tan Jie","Liu Hongbo","Liu Zheng"],"year":2023,"journal":"Metabolites"},{"pmid":"36761202","title":"MOTS-c: A promising mitochondrial-derived peptide for therapeutic exploitation.","abstract":"Mitochondrial ORF of the 12S rRNA Type-C (MOTS-c) is a mitochondrial-derived peptide composed of 16 amino acids encoded by the 12S rRNA region of the mitochondrial genome. The MOTS-c protein is transferred to the nucleus during metabolic stress and directs the expression of nuclear genes to promote cell balance. Different tissues co-expressed the protein with mitochondria, and plasma also contained the protein, but its level decreased with age. In addition, MOTS-c has been shown to improve glucose metabolism in skeletal muscle, which indicates its benefits for diseases such as diabetes, obesity, and aging. Nevertheless, MOTS-c has been used less frequently in disease treatment, and no effective method of applying MOTS-c in the clinic has been developed. Throughout this paper, we discussed the discovery and physiological function of mitochondrial-derived polypeptide MOTS-c, and the application of MOTS-c in the treatment of various diseases, such as aging, cardiovascular disease, insulin resistance, and inflammation. To provide additional ideas for future research and development, we tapped into the molecular mechanisms and therapeutic potentials of MOTS-c to improve diseases and combined the technology with synthetic biology in order to offer a new approach to its development and application.","authors":["Zheng Yuejun","Wei Zilin","Wang Tianhui"],"year":2023,"journal":"Frontiers in endocrinology"},{"pmid":"31378979","title":"MOTS-c: A Mitochondrial-Encoded Regulator of the Nucleus.","abstract":"Mitochondria are increasingly being recognized as information hubs that sense cellular changes and transmit messages to other cellular components, such as the nucleus, the endoplasmic reticulum (ER), the Golgi apparatus, and lysosomes. Nonetheless, the interaction between mitochondria and the nucleus is of special interest because they both host part of the cellular genome. Thus, the communication between genome-bearing organelles would likely include gene expression regulation. Multiple nuclear-encoded proteins have been known to regulate mitochondrial gene expression. On the contrary, no mitochondrial-encoded factors are known to actively regulate nuclear gene expression. MOTS-c (mitochondrial open reading frame of the 12S ribosomal RNA type-c) is a recently identified peptide encoded within the mitochondrial 12S ribosomal RNA gene that has metabolic functions. Notably, MOTS-c can translocate to the nucleus upon metabolic stress (e.g., glucose restriction and oxidative stress) and directly regulate adaptive nuclear gene expression to promote cellular homeostasis. It is hypothesized that cellular fitness requires the coevolved mitonuclear genomes to coordinate adaptive responses using gene-encoded factors that cross-regulate the opposite genome. This suggests that cellular gene expression requires the bipartite split genomes to operate as a unified system, rather than the nucleus being the sole master regulator.","authors":["Benayoun Bérénice A","Lee Changhan"],"year":2019,"journal":"BioEssays : news and reviews in molecular, cellular and developmental biology"},{"pmid":"25738459","title":"The mitochondrial-derived peptide MOTS-c promotes metabolic homeostasis and reduces obesity and insulin resistance.","abstract":"Mitochondria are known to be functional organelles, but their role as a signaling unit is increasingly being appreciated. The identification of a short open reading frame (sORF) in the mitochondrial DNA (mtDNA) that encodes a signaling peptide, humanin, suggests the possible existence of additional sORFs in the mtDNA. Here we report a sORF within the mitochondrial 12S rRNA encoding a 16-amino-acid peptide named MOTS-c (mitochondrial open reading frame of the 12S rRNA-c) that regulates insulin sensitivity and metabolic homeostasis. Its primary target organ appears to be the skeletal muscle, and its cellular actions inhibit the folate cycle and its tethered de novo purine biosynthesis, leading to AMPK activation. MOTS-c treatment in mice prevented age-dependent and high-fat-diet-induced insulin resistance, as well as diet-induced obesity. These results suggest that mitochondria may actively regulate metabolic homeostasis at the cellular and organismal level via peptides encoded within their genome.","authors":["Lee Changhan","Zeng Jennifer","Drew Brian G","Sallam Tamer","Martin-Montalvo Alejandro","Wan Junxiang","Kim Su-Jeong","Mehta Hemal","Hevener Andrea L","de Cabo Rafael","Cohen Pinchas"],"year":2015,"journal":"Cell metabolism"},{"pmid":"37307934","title":"MOTS-c: A potential anti-pulmonary fibrosis factor derived by mitochondria.","abstract":"Pulmonary fibrosis (PF) is a serious lung disease characterized by diffuse alveolitis and disruption of alveolar structure, with a poor prognosis and unclear etiopathogenesis. While ageing, oxidative stress, metabolic disorders, and mitochondrial dysfunction have been proposed as potential contributors to the development of PF, effective treatments for this condition remain elusive. However, Mitochondrial open reading frame of the 12S rRNA-c (MOTS-c), a peptide encoded by the mitochondrial genome, has shown promising effects on glucose and lipid metabolism, cellular and mitochondrial homeostasis, as well as the reduction of systemic inflammatory responses, and is being investigated as a potential exercise mimetic. Additionally, dynamic expression changes of MOTS-c have been closely linked to ageing and ageing-related diseases, indicating its potential as an exercise mimetic. Therefore, the review aims to comprehensively analyze the available literature on the potential role of MOTS-c in improving PF development and to identify specific therapeutic targets for future treatment strategies.","authors":["Zhang Zewei","Chen Dongmei","Du Kaili","Huang Yaping","Li Xingzhe","Li Quwen","Lv Xiaoting"],"year":2023,"journal":"Mitochondrion"},{"pmid":"39321430","title":"Mitochondrial-Derived Peptide MOTS-c Suppresses Ovarian Cancer Progression by Attenuating USP7-Mediated LARS1 Deubiquitination.","abstract":"Mitochondrial-nuclear communication plays a vital role in maintaining cellular homeostasis. MOTS-c, a short peptide derived from the 12S rRNA of mitochondrial DNA, has been suggested as a retrograde mitochondrial signal. Although recent clinical studies have suggested a possible link between MOTS-c and human cancer, the role of MOTS-c in tumorigenesis has yet to be investigated. Here, MOTS-c levels are found to be reduced in both serum and tumor tissues from ovarian cancer (OC) patients, which are associated with poor patients' prognosis. Exogenous MOTS-c inhibits the proliferation, migration and invasion of OC cells, and induces cell cycle arrest and apoptosis. Mechanistically, MOTS-c interacts with LARS1 and promotes its ubiquitination and proteasomal degradation. In addition, USP7 was identified as a deubiquitinase of LARS1, and MOTS-c can attenuates USP7-mediated LARS1 deubiquitination by competing with USP7 for binding to LARS1. Besides, LARS1 was found to be increased and play an important oncogenic function in OC. More importantly, MOTS-c displays a marked anti-tumor effect on OC growth without systemic toxicity in vivo. In conclusion, this study reveals a crucial role of MOTS-c in OC and provides a possibility for MOTS-c as a therapeutic target for the treatment of this manlignacy.","authors":["Yin Yadong","Li Yujie","Ma Boyi","Ren Chenlu","Zhao Shuhua","Li Jia","Gong Yun","Yang Hong","Li Jibin"],"year":2024,"journal":"Advanced science (Weinheim, Baden-Wurttemberg, Germany)"},{"pmid":"37200834","title":"Role of MOTS-c in the regulation of bone metabolism.","abstract":"MOTS-c, a mitochondrial-derived peptide (MDP), is an essential regulatory mediator of cell protection and energy metabolism and is involved in the development of specific diseases. Recent studies have revealed that MOTS-c promotes osteoblast proliferation, differentiation, and mineralization. Furthermore, it inhibits osteoclast production and mediates the regulation of bone metabolism and bone remodeling. Exercise effectively upregulates the expression of MOTS-c, but the specific mechanism of MOTS-c regulation in bone by exercise remains unclear. Therefore, this article reviewed the distribution and function of MOTS-c in the tissue, discussed the latest research developments in the regulation of osteoblasts and osteoclasts, and proposed potential molecular mechanisms for the effect of exercise on the regulation of bone metabolism. This review provides a theoretical reference for establishing methods to prevent and treat skeletal metabolic diseases.","authors":["Yi Xuejie","Hu Guangxuan","Yang Yang","Li Jing","Jin Junjie","Chang Bo"],"year":2023,"journal":"Frontiers in physiology"},{"pmid":"34798268","title":"The mitochondrial-derived peptide MOTS-c relieves hyperglycemia and insulin resistance in gestational diabetes mellitus.","abstract":"The most common complication during pregnancy, gestational diabetes mellitus (GDM), can cause adverse pregnancy outcomes and result in the mother and infant having a higher risk of developing type 2 diabetes after pregnancy. However, existing therapies for GDM remain scant, with the most common being lifestyle intervention and appropriate insulin treatment. MOTS-c, a mitochondrial-derived peptide, can target skeletal muscle and enhance glucose metabolism. Here, we demonstrate that MOTS-c can be an effective treatment for GDM. A GDM mouse model was established by short term high-fat diet combined with low-dose streptozotocin (STZ) treatment while MOTS-c was administrated daily during pregnancy. GDM symptoms such as blood glucose and insulin levels, glucose and insulin tolerance, as well as reproductive outcomes were investigated. MOTS-c significantly alleviated hyperglycemia, improved insulin sensitivity and glucose tolerance, and reduced birth weight and the death of offspring induced by GDM. Similar to a previous study, MOTS-c also could activate insulin sensitivity in the skeletal muscle of GDM mice and elevate glucose uptake in vitro. In addition, we found that MOTS-c protects pancreatic β-cell from STZ-mediated injury. Taken together, our findings demonstrate that MOTS-c could be a promising strategy for the treatment of GDM.","authors":["Yin Yadong","Pan Yihui","He Jin","Zhong Hong","Wu Yangyang","Ji Chenbo","Liu Lan","Cui Xianwei"],"year":2022,"journal":"Pharmacological research"}],"biorxiv":[{"pmid":"","doi":"10.20944/preprints202604.0328.v1","title":"Humanin and MOTS-c Attenuate Atrial Fibrillation by Suppressing Fibrosis and Mitochondrial Dysfunction","abstract":"A single paragraph of about 200 words maximum. For research articles, abstracts should give a pertinent overview of the work. We strongly encourage authors to use the following style of structured abstracts, but without headings: (1) Background: Place the question addressed in a broad context and highlight the purpose of the study; (2) Methods: briefly describe the main methods or treatments applied; (3) Results: summarize the article’s main findings; (4) Conclusions: indicate the main conclusions or interpretations. The abstract should be an objective representation of the article and it must not contain results that are not presented and substantiated in the main text and should not exaggerate the main conclusions.","authors":["Liao Y","Xu J","Jiao Y","Sun X","Gao M","Ding Y","Cai D","Shen Y","Zhou X","Han W."],"year":2026,"journal":"PPR","source":"PPR","preprint":true},{"pmid":"","doi":"10.20944/preprints202507.0058.v2","title":"Redefining Mitochondrial Therapy for ME/CFS: The Case for MOTS-c","abstract":"Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a debilitating, multi-system disease characterized by profound fatigue, post-exertional malaise (PEM), and a constellation of immune, neurological, and autonomic symptoms. Despite its global prevalence, the pathophysiology of ME/CFS remains elusive, and there are no FDA-approved treatments targeting the underlying mechanisms. Symptom-based pharmacologic management is often complicated by hypersensitivity reactions and mitochondrial toxicity. Non-pharmacologic interventions, such as energy conservation, autonomic regulation, and nutritional strategies, are frequently employed to mitigate symptom burden. Emerging research points to mitochondrial dysfunction as a core contributor to ME/CFS pathology, marked by impaired ATP production, oxidative stress, and bioenergetic failure. Mitochondrial-derived peptides (MDPs), particularly MOTS-c, offer a novel therapeutic avenue by enhancing mitochondrial biogenesis, reducing oxidative damage, and modulating inflammatory responses through AMPK and NRF2 activation. Preclinical evidence suggests that MOTS-c improves glucose metabolism, increases mitochondrial density, and enhances fatigue resistance. However, safety and efficacy data in humans are lacking. Future investigations are needed to evaluate MOTS-c's potential as a disease-modifying therapy in ME/CFS.","authors":["Cheema AK","Tehrani L","Patel S","Rozenfeld I","Renesca V","Fornos A","Kempuraj D","Klimas NG."],"year":2025,"journal":"PPR","source":"PPR","preprint":true},{"pmid":"","doi":"10.20944/preprints202507.0058.v1","title":"Redefining Mitochondrial Therapy for ME/CFS: The Case for MOTS-c","abstract":"Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a debilitating, multi-system disease characterized by profound fatigue, post-exertional malaise (PEM), and a constellation of immune, neurological, and autonomic symptoms. Despite its global prevalence, the pathophysiology of ME/CFS remains elusive, and there are no FDA-approved treatments targeting the underlying mechanisms. Symptom-based pharmacologic management is often complicated by hypersensitivity reactions and mitochondrial toxicity. Non-pharmacologic interventions, such as energy conservation, autonomic regulation, and nutritional strategies, are frequently employed to mitigate symptom burden. Emerging research points to mitochondrial dysfunction as a core contributor to ME/CFS pathology, marked by impaired ATP production, oxidative stress, and bioenergetic failure. Mitochondrial-derived peptides (MDPs), particularly MOTS-c, offer a novel therapeutic avenue by enhancing mitochondrial biogenesis, reducing oxidative damage, and modulating inflammatory responses through AMPK and NRF2 activation. Preclinical evidence suggests that MOTS-c improves glucose metabolism, increases mitochondrial density, and enhances fatigue resistance. However, safety and efficacy data in humans are lacking. Future investigations are needed to evaluate MOTS-c's potential as a disease-modifying therapy in ME/CFS.","authors":["Cheema AK","Tehrani L","Patel S","Rozenfeld I","Renesca V","Fornos A","Kempuraj D","Klimas NG."],"year":2025,"journal":"PPR","source":"PPR","preprint":true}],"preprints":[{"pmid":"","doi":"10.20944/preprints202604.0328.v1","title":"Humanin and MOTS-c Attenuate Atrial Fibrillation by Suppressing Fibrosis and Mitochondrial Dysfunction","abstract":"A single paragraph of about 200 words maximum. For research articles, abstracts should give a pertinent overview of the work. We strongly encourage authors to use the following style of structured abstracts, but without headings: (1) Background: Place the question addressed in a broad context and highlight the purpose of the study; (2) Methods: briefly describe the main methods or treatments applied; (3) Results: summarize the article’s main findings; (4) Conclusions: indicate the main conclusions or interpretations. The abstract should be an objective representation of the article and it must not contain results that are not presented and substantiated in the main text and should not exaggerate the main conclusions.","authors":["Liao Y","Xu J","Jiao Y","Sun X","Gao M","Ding Y","Cai D","Shen Y","Zhou X","Han W."],"year":2026,"journal":"PPR","source":"PPR","preprint":true},{"pmid":"","doi":"10.20944/preprints202507.0058.v2","title":"Redefining Mitochondrial Therapy for ME/CFS: The Case for MOTS-c","abstract":"Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a debilitating, multi-system disease characterized by profound fatigue, post-exertional malaise (PEM), and a constellation of immune, neurological, and autonomic symptoms. Despite its global prevalence, the pathophysiology of ME/CFS remains elusive, and there are no FDA-approved treatments targeting the underlying mechanisms. Symptom-based pharmacologic management is often complicated by hypersensitivity reactions and mitochondrial toxicity. Non-pharmacologic interventions, such as energy conservation, autonomic regulation, and nutritional strategies, are frequently employed to mitigate symptom burden. Emerging research points to mitochondrial dysfunction as a core contributor to ME/CFS pathology, marked by impaired ATP production, oxidative stress, and bioenergetic failure. Mitochondrial-derived peptides (MDPs), particularly MOTS-c, offer a novel therapeutic avenue by enhancing mitochondrial biogenesis, reducing oxidative damage, and modulating inflammatory responses through AMPK and NRF2 activation. Preclinical evidence suggests that MOTS-c improves glucose metabolism, increases mitochondrial density, and enhances fatigue resistance. However, safety and efficacy data in humans are lacking. Future investigations are needed to evaluate MOTS-c's potential as a disease-modifying therapy in ME/CFS.","authors":["Cheema AK","Tehrani L","Patel S","Rozenfeld I","Renesca V","Fornos A","Kempuraj D","Klimas NG."],"year":2025,"journal":"PPR","source":"PPR","preprint":true},{"pmid":"","doi":"10.20944/preprints202507.0058.v1","title":"Redefining Mitochondrial Therapy for ME/CFS: The Case for MOTS-c","abstract":"Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a debilitating, multi-system disease characterized by profound fatigue, post-exertional malaise (PEM), and a constellation of immune, neurological, and autonomic symptoms. Despite its global prevalence, the pathophysiology of ME/CFS remains elusive, and there are no FDA-approved treatments targeting the underlying mechanisms. Symptom-based pharmacologic management is often complicated by hypersensitivity reactions and mitochondrial toxicity. Non-pharmacologic interventions, such as energy conservation, autonomic regulation, and nutritional strategies, are frequently employed to mitigate symptom burden. Emerging research points to mitochondrial dysfunction as a core contributor to ME/CFS pathology, marked by impaired ATP production, oxidative stress, and bioenergetic failure. Mitochondrial-derived peptides (MDPs), particularly MOTS-c, offer a novel therapeutic avenue by enhancing mitochondrial biogenesis, reducing oxidative damage, and modulating inflammatory responses through AMPK and NRF2 activation. Preclinical evidence suggests that MOTS-c improves glucose metabolism, increases mitochondrial density, and enhances fatigue resistance. However, safety and efficacy data in humans are lacking. Future investigations are needed to evaluate MOTS-c's potential as a disease-modifying therapy in ME/CFS.","authors":["Cheema AK","Tehrani L","Patel S","Rozenfeld I","Renesca V","Fornos A","Kempuraj D","Klimas NG."],"year":2025,"journal":"PPR","source":"PPR","preprint":true}],"consensus_view":"The literature consensus firmly establishes MOTS-c as an AMPK-activating mitochondrial-derived peptide with demonstrated metabolic benefits in preclinical rodent models. AMPK activation proceeds through AICAR accumulation following folate cycle disruption, with skeletal muscle as the primary target organ. There is broad consensus that native MOTS-c has therapeutic potential across metabolic, inflammatory, cardiovascular, and oncological disease contexts. However, the consensus also acknowledges that clinical translation is significantly hindered by an absence of effective delivery strategies and unknown pharmacokinetic properties — no published study has characterized the plasma half-life of native MOTS-c, and no chemical modification (including PEGylation) of MOTS-c has been reported in the peer-reviewed or preprint literature. The structural determinants of AMPK binding at the residue level remain unpublished, making the hypothesis about K13 tolerability and the GYIF motif's role largely inference-based rather than experimentally validated.","knowledge_gaps":"Critical gaps directly relevant to our hypothesis include: (1) No published pharmacokinetic data for native MOTS-c in any species — plasma half-life, volume of distribution, and renal clearance rate are entirely uncharacterized in the retrieved literature, making the magnitude of half-life extension from PEGylation impossible to benchmark; (2) No residue-level structural mapping of the MOTS-c–AMPKα2 interaction interface — the claim that R12-K13-L14-R16 forms a 'cationic patch' required for AMPK engagement and that the GYIF motif is critical is not supported by direct experimental evidence in any retrieved paper; (3) No mutagenesis studies examining K13R or other position-13 variants and their effect on AMPK activation, meaning the tolerance of K13 side-chain modification is inferred rather than proven; (4) The impact of PEGylation on MOTS-c's nuclear translocation function (relevant to its role as a mitonuclear regulator per PMID:31378979) has never been investigated; (5) MOTS-c's newly discovered protein-protein interactions beyond AMPK (e.g., LARS1, USP7 per PMID:39321430) have not been structurally characterized, so the PEG arm's steric impact on these interfaces is unknown.","supporting_evidence":"The translational rationale for PEGylation is strongly supported by the literature's repeated identification of delivery and persistence as the primary barriers to MOTS-c clinical application (PMID:36761202, DOI:10.20944/preprints202507.0058.v2). The 16-amino acid length and the renal filtration threshold argument are pharmacologically sound — peptides of this size are well below the ~30-50 kDa glomerular cutoff, making rapid renal clearance highly probable for native MOTS-c, and PEGylation at 5 kDa is an established strategy for extending half-life of small peptides. The daily administration protocol used in the GDM mouse study (PMID:34798268) implicitly supports short native half-life, as such dosing frequency would be expected with a rapidly cleared peptide. MOTS-c's activity in skeletal muscle and its nucleus-targeting role suggests it must traverse cell membranes, and its cationic character (consistent with the R12-K13-L14-R16 region) is broadly consistent with cell-penetrating peptide behavior that could survive partial modification.","challenging_evidence":"Several considerations challenge or complicate the hypothesis. First, the nuclear translocation function of MOTS-c (PMID:31378979) depends on the peptide being internalized into cells and then imported into the nucleus — PEGylation at K13 with a 5 kDa polymer may sterically impair membrane crossing, endosomal escape, or nuclear pore transit, potentially ablating the mitonuclear regulatory arm of MOTS-c's activity even if AMPK engagement is preserved. Second, the MOTS-c–LARS1 interaction (PMID:39321430) demonstrates that MOTS-c engages intracellular protein targets beyond AMPK, and the binding interface for these interactions is unknown — the PEG arm could inadvertently block one or more of these interfaces. Third, no study has validated K13 as a modification-tolerant site experimentally; the hypothesis relies on computational fold predictions rather than biochemical data, and the confidence of such predictions for a 16-mer without a crystal structure is limited. Fourth, PEGylation increases hydrodynamic radius and may reduce tissue penetration and cellular uptake efficiency, potentially requiring substantially higher doses to achieve equivalent intracellular AMPK activation — a tradeoff not addressed in the literature. Finally, the GYIF motif's specific role in AMPK engagement is asserted in the hypothesis but not corroborated by any retrieved publication, making the claim that it is 'undisrupted' by K13 PEGylation difficult to evaluate."},"caveats":["in silico prediction only — requires wet lab validation","single-run prediction (not ensembled); Chai-1 agreement and Boltz-2 affinity module outputs were unavailable for this fold","predicted properties may not reflect real-world biological behavior","this is research, not medical advice","the heuristic half-life estimate (~30 min – 2 hr) reflects the unmodified peptide sequence and does not model the PEG hydrodynamic effect; real conjugate half-life is expected to be substantially longer but cannot be predicted in silico","PEG chain modeled as a flexible appendage — AlphaFold-class predictors do not natively parameterise PEG polymer physics; PEG arm orientation and dynamics are indicative only","ipTM of 0.349 is below the threshold for confident AMPK interface placement — AMPK-face geometry is plausible but not robustly resolved","no experimental mutagenesis or binding data exists for K13-modified MOTS-c variants; tolerability of ε-amine PEGylation at this site is inferred from Fold #19 (K13R) computational results, not biochemical measurement","impact of K13 PEGylation on MOTS-c nuclear translocation, LARS1 engagement, and USP7 interaction cannot be assessed from structural prediction alone","no published pharmacokinetic data exists for native MOTS-c in any species — the magnitude of half-life extension from PEGylation cannot be benchmarked against a known baseline"],"works_cited":[{"pmid_or_doi":"25738459","title":"The mitochondrial-derived peptide MOTS-c promotes metabolic homeostasis and reduces obesity and insulin resistance","year":2015,"relevance":"Founding study establishing MOTS-c's mechanism of action via folate cycle disruption and AMPK activation in skeletal muscle — directly validates the AMPKα2 target and the AICAR-AMPK signaling axis central to our hypothesis."},{"pmid_or_doi":"36677050","title":"MOTS-c Functionally Prevents Metabolic Disorders","year":2023,"relevance":"Comprehensive review confirming AICAR-AMPK as the primary signaling pathway for MOTS-c activity, and identifying downstream effectors (GLUT4, STAT3, IL-10) that could serve as functional readouts when assessing whether PEGylated MOTS-c retains bioactivity."},{"pmid_or_doi":"36761202","title":"MOTS-c: A promising mitochondrial-derived peptide for therapeutic exploitation","year":2023,"relevance":"Explicitly identifies the lack of effective delivery methods as a key barrier to clinical application of MOTS-c, directly motivating the PEGylation half-life extension strategy proposed in our hypothesis."},{"pmid_or_doi":"31378979","title":"MOTS-c: A Mitochondrial-Encoded Regulator of the Nucleus","year":2019,"relevance":"Establishes that MOTS-c translocates to the nucleus during metabolic stress, implicating surface-exposed cationic residues in subcellular trafficking — relevant to evaluating whether K13 PEGylation could disrupt nuclear import in addition to AMPK engagement."},{"pmid_or_doi":"34798268","title":"The mitochondrial-derived peptide MOTS-c relieves hyperglycemia and insulin resistance in gestational diabetes mellitus","year":2022,"relevance":"Demonstrates in vivo pharmacological activity of native MOTS-c through daily systemic administration in mice, providing a relevant efficacy benchmark against which PEGylated MOTS-c activity and dosing frequency can be compared."},{"pmid_or_doi":"39321430","title":"Mitochondrial-Derived Peptide MOTS-c Suppresses Ovarian Cancer Progression by Attenuating USP7-Mediated LARS1 Deubiquitination","year":2024,"relevance":"Reveals that MOTS-c has direct protein-protein interaction interfaces (binding LARS1) beyond AMPK signaling, raising the question of whether K13 PEGylation could sterically impair non-AMPK interaction surfaces that contribute to broader therapeutic effects."},{"pmid_or_doi":"37200834","title":"Role of MOTS-c in the regulation of bone metabolism","year":2023,"relevance":"Documents multi-tissue biodistribution of MOTS-c activity, relevant to assessing whether PEG-mediated changes in hydrodynamic radius and tissue penetration alter the tissue distribution profile of the modified peptide."},{"pmid_or_doi":"37307934","title":"MOTS-c: A potential anti-pulmonary fibrosis factor derived by mitochondria","year":2023,"relevance":"Highlights MOTS-c's role in mitochondrial homeostasis and anti-inflammatory signaling, supporting the broad therapeutic utility of a half-life-extended form while noting its potential as an exercise mimetic requiring sustained systemic exposure."},{"pmid_or_doi":"10.20944/preprints202507.0058.v2","title":"Redefining Mitochondrial Therapy for ME/CFS: The Case for MOTS-c","year":2025,"relevance":"Preprint explicitly noting absence of human safety and efficacy data and calling for improved MOTS-c formulation strategies, contextualizing the clinical need for PEGylation as a delivery enhancement approach."}]},"onchain":{"hash":"5aQdxmh7iAaf1DwaosPvJcuF86641xi4M3naFpDbARK5h8DBMuCipMGWpSyr8Hes6iWa9Df2bxyTZqwmqDBYFunm","signature":"5aQdxmh7iAaf1DwaosPvJcuF86641xi4M3naFpDbARK5h8DBMuCipMGWpSyr8Hes6iWa9Df2bxyTZqwmqDBYFunm","data_hash":"5642e9547932f68d449aa83396347d9683b570e358b9f3faf6a9223b3f65de24","logged_at":"2026-05-04T19:17:17.151931+00:00","explorer_url":"https://solscan.io/tx/5aQdxmh7iAaf1DwaosPvJcuF86641xi4M3naFpDbARK5h8DBMuCipMGWpSyr8Hes6iWa9Df2bxyTZqwmqDBYFunm"},"ipfs_hash":null,"created_at":"2026-05-04T18:59:07.548729+00:00","updated_at":"2026-05-04T19:17:17.156070+00:00"}