SS-31 and MOTS-c: Two Mitochondrial Peptides Explained

Scientifically reviewed by
Dr. Ky H. Le, MD

The information presented in this article is for educational and research purposes only, intended for laboratory professionals, researchers and collaborators. This content does not constitute medical or clinical advice.

Mitochondrial peptides represent an exciting class of research compounds that target cellular powerhouses. Two peptides stand out for their distinct approaches to mitochondrial function: SS-31 (elamipretide) and MOTS-c.

These compounds work through different pathways but share a common goal. Both target mitochondrial dysfunction, which plays a central role in aging and metabolic disorders.

Key Research Insights

• SS-31 is a lab-made peptide that protects the membranes inside mitochondria from damage.
• MOTS-c is a natural peptide that helps cells communicate about energy needs and metabolism.
• The two peptides work through completely different pathways, making them useful for studying different aspects of cell function.
• Both show promise for research into aging, heart health, brain protection, and metabolic disorders.

Peptide Comparison Overview

Characteristic	SS-31 (Elamipretide)	MOTS-c
Origin	Synthetic tetrapeptide	Endogenous mitochondrial-encoded peptide
Primary Target	Cardiolipin stabilization	AMPK pathway activation
Mechanism	Direct membrane protection	Nuclear gene regulation
Research Focus	Cardiovascular and neurological studies	Metabolic and aging research
Clinical Stage	Phase 2 trials completed	Preclinical research phase

What is SS-31 (Elamipretide)?

SS-31 is a synthetic tetrapeptide with the sequence D-Arg-dimethylTyr-Lys-Phe-NH2. Researchers designed this compound to target mitochondrial dysfunction at its source.

The peptide’s unique structure allows it to cross cellular membranes easily. Once inside mitochondria, it binds to specific lipid molecules that keep these organelles functioning properly.

How SS-31 Works

SS-31’s primary target is cardiolipin, a unique phospholipid found only in mitochondrial membranes[1]. This lipid makes up about 15-20% of total mitochondrial lipids and is critical for energy production.

The peptide’s positive charges help it attach to membrane surfaces. Once bound to cardiolipin, SS-31 prevents cytochrome c from becoming a destructive enzyme[2].

This protection maintains the structural integrity of mitochondrial cristae. The result is improved oxidative phosphorylation and better ATP production[3].

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SS-31 Research Findings

Cardiovascular Research

Clinical studies show promising results for heart-related applications. Research in patients with renal artery stenosis demonstrated that elamipretide during stent procedures improved kidney blood flow[4].

Studies in aging models show SS-31 reduces excessive proton leak in heart muscle cells. This effect essentially rejuvenates mitochondrial function in aged tissue[5].

ATP recovery after ischemic injury also improves with SS-31 treatment. The peptide stabilizes mitochondrial structure during stress conditions[6].

Neurological Research

Brain-related studies reveal multiple protective effects. SS-31 improves functional connectivity in the hippocampus following inflammation[7].

Research shows the peptide enhances mitochondrial development in brains exposed to anesthesia[7]. This suggests potential applications for protecting developing neural tissue.

Studies in traumatic brain injury models demonstrate reduced mitochondrial dysfunction after SS-31[8].

Musculoskeletal Research

Clinical trials in older adults show that a single SS-31 dose elevated mitochondrial energy capacity in skeletal muscle[4]. This finding suggests potential for studying age-related muscle decline.

Research in tendon tissue shows SS-31 improves mitochondrial function in degenerative cells[9]. This opens possibilities for studying connective tissue disorders.

Related Product: Buy MOTS-c for laboratory research use.

What is MOTS-c?

MOTS-c (Mitochondrial Open reading frame of the 12S rRNA-c) is a 16-amino acid peptide. Unlike SS-31, MOTS-c occurs naturally and is encoded by mitochondrial DNA[10].

This peptide represents a communication system between mitochondria and the cell nucleus. It acts as a retrograde signaling molecule that coordinates cellular responses to energy demands.

How MOTS-c Works

MOTS-c works through the folate-AICAR-AMPK pathway[11]. The peptide disrupts the folate cycle and associated purine synthesis pathways.

This disruption leads to accumulation of AICAR (5-aminoimidazole-4-carboxamide ribonucleotide). AICAR then activates AMPK, a master regulator of cellular energy[12].

During metabolic stress, MOTS-c can move to the nucleus where it regulates gene expression[13]. This represents a novel mechanism for mitochondrial control of nuclear genes.

MOTS-c Research Findings

Metabolic Research

Studies show MOTS-c promotes glucose uptake in skeletal muscle tissue. The peptide also enhances insulin sensitivity in research models[11].

Research in diet-induced obesity models demonstrates that MOTS-c treatment prevents weight gain. The peptide improves metabolic homeostasis in aged mice as well[12].

Treatment reduces insulin resistance and improves glucose tolerance. These effects occur through AMPK-mediated pathways[14].

Neurological Research

MOTS-c shows neuroprotective effects by activating Nrf2-dependent antioxidant pathways. This mechanism helps protect brain tissue from oxidative damage[15].

In traumatic brain injury models, the peptide improves memory, learning, and motor function. It also reduces neuroinflammation markers[16].

Research shows promise for treating diabetic neuropathy through AMPK-mediated mitochondrial biogenesis[17].

Clinical Correlations

Human studies reveal that circulating MOTS-c levels decline with aging. Lower levels correlate with poorer metabolic health[10].

Research shows MOTS-c levels negatively correlate with insulin resistance. Higher levels associate with better metabolic markers[18].

Studies in COVID-19 patients show elevated MOTS-c levels. This may represent a compensatory response to viral-induced mitochondrial stress[19].

Future Research Directions

Both peptides continue to generate research interest through different approaches. SS-31 advances through clinical development while MOTS-c research expands in preclinical models.

SS-31 Development

Structure-activity relationship studies explore SS-31 analogs with improved properties[20]. Researchers seek compounds with better tissue penetration or longer half-lives.

Clinical trials continue to expand into new therapeutic areas. Current studies examine applications in heart failure, primary mitochondrial diseases, and age-related disorders.

MOTS-c Research

Scientists are developing novel delivery methods for MOTS-c, including cell-penetrating peptide conjugates[21]. These approaches aim to improve brain uptake and tissue-specific targeting.

Research explores the peptide’s role in different disease models. Studies examine applications in metabolic disorders, neurodegenerative diseases, and aging research.

Synergistic Potential

The complementary mechanisms of SS-31 and MOTS-c suggest potential for combined research applications. SS-31 provides immediate mitochondrial stabilization while MOTS-c coordinates longer-term adaptive responses.

This combination approach could offer advantages for studying complex mitochondrial dysfunction. Different research models may benefit from targeting both membrane stability and metabolic signaling.

In Vitro Research Applications

Application	SS-31	MOTS-c	Research Focus
Mitochondrial Function	Cardiolipin stabilization assays	AMPK activation studies	Energy metabolism
Oxidative Stress	ROS production measurements	Antioxidant pathway analysis	Cellular protection
Metabolic Studies	ATP synthesis evaluation	Glucose uptake assays	Energy homeostasis
Aging Research	Mitochondrial morphology	Gene expression changes	Cellular senescence
Neuroprotection	Synaptic function tests	Neuroinflammation markers	Brain cell survival

Research Applications Summary

SS-31 and MOTS-c represent two distinct approaches to studying mitochondrial function. Their different mechanisms make them valuable tools for investigating various aspects of cellular energy metabolism.

SS-31 excels in studies requiring direct mitochondrial membrane stabilization. MOTS-c offers unique insights into mitochondrial-nuclear communication pathways.

Both peptides provide researchers with precise tools for investigating age-related mitochondrial decline. Their distinct mechanisms allow for comprehensive studies of mitochondrial dysfunction in laboratory settings.

These peptides are intended for research use only and are not intended for human consumption or therapeutic use.

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References

1. A. V. Birk et al., “The Mitochondrial-Targeted Compound SS-31 Re-Energizes Ischemic Mitochondria by Interacting with Cardiolipin,” Ovid Technologies (Wolters Kluwer Health), Aug. 2013. doi: 10.1681/asn.2012121216. https://doi.org/10.1681/asn.2012121216
2. A. V. Birk, W. M. Chao, C. Bracken, J. D. Warren, and H. H. Szeto, “Targeting mitochondrial cardiolipin and the cytochrome c/cardiolipin complex to promote electron transport and optimize mitochondrial ATP synthesis,” Wiley, Mar. 2014. doi: 10.1111/bph.12468. https://doi.org/10.1111/bph.12468
3. H. H. Szeto, “First‐in‐class cardiolipin‐protective compound as a therapeutic agent to restore mitochondrial bioenergetics,” Wiley, Mar. 2014. doi: 10.1111/bph.12461. https://doi.org/10.1111/bph.12461
4. J. D. Chavez et al., “Mitochondrial protein interaction landscape of SS-31,” Cold Spring Harbor Laboratory, Aug. 2019. doi: 10.1101/739128. https://doi.org/10.1101/739128
5. H. Zhang, N. N. Alder, W. Wang, H. Szeto, D. J. Marcinek, and P. S. Rabinovitch, “Reduction of elevated proton leak rejuvenates mitochondria in the aged cardiomyocyte,” eLife Sciences Publications, Ltd, Dec. 2020. doi: 10.7554/elife.60827. https://doi.org/10.7554/elife.60827
6. H. H. Szeto et al., “Mitochondria-Targeted Peptide Accelerates ATP Recovery and Reduces Ischemic Kidney Injury,” Ovid Technologies (Wolters Kluwer Health), Jun. 2011. doi: 10.1681/asn.2010080808. https://doi.org/10.1681/asn.2010080808
7. Y. Zhu et al., “SS‐31 Provides Neuroprotection by Reversing Mitochondrial Dysfunction after Traumatic Brain Injury,” Wiley, Jan. 2018. doi: 10.1155/2018/4783602. https://doi.org/10.1155/2018/4783602
8. Y. Liu et al., “Elamipretide (SS-31) Improves Functional Connectivity in Hippocampus and Other Related Regions Following Prolonged Neuroinflammation Induced by Lipopolysaccharide in Aged Rats,” Frontiers Media SA, Mar. 2021. doi: 10.3389/fnagi.2021.600484. https://doi.org/10.3389/fnagi.2021.600484
9. X. Zhang et al., “Evaluation of SS-31 as a Potential Strategy for Tendinopathy Treatment: An In Vitro Model,” SAGE Publications, Jul. 2022. doi: 10.1177/03635465221107943. https://doi.org/10.1177/03635465221107943
10. W. Wan et al., “Mitochondria-derived peptide MOTS-c: effects and mechanisms related to stress, metabolism and aging,” Springer Science and Business Media LLC, Jan. 2023. doi: 10.1186/s12967-023-03885-2. https://doi.org/10.1186/s12967-023-03885-2
11. C. Lee et al., “The Mitochondrial-Derived Peptide MOTS-c Promotes Metabolic Homeostasis and Reduces Obesity and Insulin Resistance,” Elsevier BV, Mar. 2015. doi: 10.1016/j.cmet.2015.02.009. https://doi.org/10.1016/j.cmet.2015.02.009
12. Y. Gao et al., “MOTS-c Functionally Prevents Metabolic Disorders,” MDPI AG, Jan. 2023. doi: 10.3390/metabo13010125. https://doi.org/10.3390/metabo13010125
13. K. H. Kim, J. M. Son, B. A. Benayoun, and C. Lee, “The Mitochondrial-Encoded Peptide MOTS-c Translocates to the Nucleus to Regulate Nuclear Gene Expression in Response to Metabolic Stress,” Elsevier BV, Sep. 2018. doi: 10.1016/j.cmet.2018.06.008. https://doi.org/10.1016/j.cmet.2018.06.008
14. S. Kim et al., “The mitochondrial‐derived peptide MOTS‐c is a regulator of plasma metabolites and enhances insulin sensitivity,” Wiley, Jul. 2019. doi: 10.14814/phy2.14171. https://doi.org/10.14814/phy2.14171
15. J. Xiao et al., “The Mitochondrial-Derived Peptide (MOTS-c) Interacted with Nrf2 to Defend the Antioxidant System to Protect Dopaminergic Neurons Against Rotenone Exposure,” Springer Science and Business Media LLC, Jun. 2023. doi: 10.1007/s12035-023-03443-3. https://doi.org/10.1007/s12035-023-03443-3
16. F. Li et al., “Neuroprotective Mechanism of MOTS-c in TBI Mice: Insights from Integrated Transcriptomic and Metabolomic Analyses,” Informa UK Limited, Jul. 2024. doi: 10.2147/dddt.s460265. https://doi.org/10.2147/dddt.s460265
17. L. Xu et al., “Mitochondria-derived peptide is an effective target for treating streptozotocin induced painful diabetic neuropathy through induction of activated protein kinase/peroxisome proliferator-activated receptor gamma coactivator 1alpha -mediated mitochondrial biogenesis,” SAGE Publications, Jan. 2024. doi: 10.1177/17448069241252654. https://doi.org/10.1177/17448069241252654
18. A. Saracaloglu, A. Ö. Mete, D. F. Ucar, S. Demiryürek, E. Erbagcı, and A. T. Demiryürek, “Evaluation of Serum Humanin and MOTS-c Peptide Levels in Patients with COVID-19 and Healthy Subjects,” Bentham Science Publishers Ltd., Mar. 2023. doi: 10.2174/1389203724666230217101202. https://doi.org/10.2174/1389203724666230217101202
19. Q. Zhou et al., “The correlation between mitochondrial derived peptide (MDP) and metabolic states: a systematic review and meta-analysis,” Springer Science and Business Media LLC, Aug. 2024. doi: 10.1186/s13098-024-01405-w. https://doi.org/10.1186/s13098-024-01405-w
20. J. Jiang et al., “Peripheral Administration of a Cell-Penetrating MOTS-c Analogue Enhances Memory and Attenuates Aβ1–42- or LPS-Induced Memory Impairment through Inhibiting Neuroinflammation,” American Chemical Society (ACS), Apr. 2021. doi: 10.1021/acschemneuro.0c00782. https://doi.org/10.1021/acschemneuro.0c00782
21. W. Mitchell et al., “Structure-Activity Relationships in the Design of Mitochondria-Targeted Peptide Therapeutics,” Cold Spring Harbor Laboratory, Nov. 2021. doi: 10.1101/2021.11.08.467832. https://doi.org/10.1101/2021.11.08.467832