Principle of Method
This assay is a competitive Enzyme Linked-Immunosorbent Assay (ELISA) kit for quantitative determination of irisin in human biological fluids (plasma, serum, cell culture supernatant). The assay also works for mouse, rat and monkey samples. A polyclonal antibody recognizing native irisin reacts with a series of predetermined recombinant irisin standard proteins or samples under competition in the irisin-coated plate. Their relative reactivity is plotted with that of the standard proteins.
Fibronectin type III domain containing (FNDC) family consists of the multiple protein species including FNDC5 also called irisin, which has been identified as a myokine capable of inducing browning of white adipose tissue leading to brown adipocytes and beige fat cells by stimulating UCP1 expression, via the PGC-1α transcriptional co-activator (3). Irisin is a single-pass type I membrane protein whose secretion could be by a putative signal peptide. Since irisin has been discovered as a soluble protein from the culture supernatant of myocytes from muscle-specific PGC-1α transgenic mice the predicted extracellular domain should be cleaved following liberation from the cell surface membrane. Indeed, this it was shown that irisin is present in culture supernatants and human/mouse sera as a 22 kDa protein (3). Irisin is able to induce UCP1 as well as a number of genes manifested in brown adipose tissues. In particular, the level of irisin was increased by muscular exercise in mouse and human, suggesting that irisin plays an important role in obesity and glucose homeostasis.
Competitive type ELISA
Fibronectin type III domain-containing protein 5, FNDC5, Fibronectin type III repeat-containing protein 2
Serum, Plasma or Cell Culture Supernatant
Though this is a human irisin assay, it also works for mouse, rat and monkey.
Serum and Plasma : 12.5 µL (actual amount of sample loaded in well after dilution)
Calibration Range: 0.001–5 μg/ml
Limit of Detection
Intra-assay (Within-Run) C.V.
Inter-assay (Run-to-Run) C.V.
Want to learn more about Irisin? We have compiled the links below which contain information that you may find interesting:
- UniProt Knowledgebase: UniProtKB - Q8NAU1 (FNDC5_HUMAN): Fibronectin type III domain-containing protein 5
- PubChem Gene Summary: FNDC5 - fibronectin type III domain containing 5 (human)
- Rabiee, Farzaneh et al. “New insights into the cellular activities of Fndc5/Irisin and its signaling pathways.” Cell & bioscience vol. 10 51. 30 Mar. 2020, doi:10.1186/s13578-020-00413-3
- Boström, Pontus et al. “A PGC1-α-dependent myokine that drives brown-fat-like development of white fat and thermogenesis.” Nature vol. 481,7382 463-8. 11 Jan. 2012, doi:10.1038/nature10777
References to Summary
- Frcp1 and Frcp2, two novel fibronectin type III repeat containing genes: Teufelet, et al.; Gene 297, 79 (2002)
- Complete sequencing and characterization of 21,243 full-length human cDNAs: T. Ota, et al.; Nat. 36, 40 (2004)
- A PGC1-α-dependent myokine that drives brown-fat-like development of white fat and thermogenesis: P. Boström, et al.; Nature 481, 463 (2012)