Irisine
| Irisine | ||
|---|---|---|
| Properties of human protein | ||
| Mass / length primary structure | 112 amino acids | |
| Precursor | FNDC5 (181 aa) | |
| Isoforms | 4 (unconfirmed) | |
| Identifier | ||
| Gene name | FNDC5 | |
| External IDs | ||
| Occurrence | ||
| Parent taxon | Vertebrates | |
Irisin is the body's own messenger substance ( cytokine ) in vertebrates . It is released by muscles and is therefore one of the myokines . It was described in 2012 by a team of researchers at Harvard University in Boston and named after the Greek messenger of the gods Iris .
During physical activity, individual proteins are increasingly formed in the muscle cells, including the protein FNDC5 ( fibronectin type III domain containing protein 5 ). FNDC5 is a membrane protein whose extracellular domain is proteolytically activated after transport to the cell membrane and secreted as irisine. There are also increased FNDC5 levels in muscle cells with increased expression of PGC-1α ( proliferator-activated receptor γ coactivator 1α ), which is important for homeostasis in the blood sugar, lipid metabolism and energy balance. Transgenic mice with permanent PGC-1α production in their muscle cells were resistant to age-dependent obesity and diabetes mellitus and had a longer life expectancy. This effect of PGC-1α takes place u. a. about the messenger substance irisin.
Irisin triggers the transformation of white fat cells into those with a phenotype of brown fat cells ("brown-in-white" or "brite" fat cells), with increased expression of the protein UCP1 ( uncoupling protein 1 , also called thermogenin), which is typical for brown fat cells . The increased expression of this protein in fat cells leads to an increased release of energy and heat generation and thus also to a slight weight loss, an increased overall energy requirement and an improved glucose tolerance.
The irisin proteins in mice and humans are identical. In humans, irisin levels doubled after ten weeks of regular physical activity. There is already speculation about an irisin therapy in the form of an exercise pill . A German study from 2013 questions the results of the American study that the greatly increased irisin levels in athletes are more likely to be due to a change in blood samples during storage. At least the German study with a larger number of test persons does not show any statistically significant changes in irisin as a result of exercise compared to a control group.
A study published in 2015 that used Western Blot to detect irisin suggests that previous ELISA- based investigations led to false-positive results, and that irisin has no physiological significance in humans and farm animals. This finding is at least partly in line with a subsequent meta-analysis in which previous studies were systematically compared and evaluated. While randomized controlled studies here suggested a tendency to decrease in irisin values through regular physical activity, non-randomized studies showed a mixed picture.
A study published in August 2015 confirmed the existence of irisin using tandem mass spectrometry .
swell
- ↑ Orthologist at eggNOG
- ↑ P. Boström, J. Wu, MP Jedrychowski, A. Korde, L. Ye, JC Lo, KA Rasbach, EA Boström, JH Choi, JZ Long, S. Kajimura, MC Zingaretti, BF Vind, H. Tu, S. Cinti, K. Højlund, SP Gygi, BM Spiegelman: A PCG1-α-dependent myokine that drives brown-fat-like development of white fat and thermogenesis . Nature January 11, 2012; Volume 481 (7382): pages 463-468.
- ↑ T. Wenz, SG Rossi, RL Rotundo, BM Spiegelman, CT Moraes: Increased PCG1-α expression protects form sarcopenia and metabolic disease during aging . Proc Natl Acad Sci USA 2009; Volume 106: Pages 20405-20410.
- ↑ Bente Klarlund Pedersen: A muscular twist on the fate of fat . New England Journal of Medicine April 19, 2012; Volume 366, pages 1544-1545.
- ↑ Anne Hecksteden, Melissa Wegmann, Anke Steffen, Jochen Kraushaar, Arne Morsch, Sandra Ruppenthal, Lars Kaestner, Tim Meyer: irisin and exercise workout in humans - Results from a randomized controlled trial workout. In: BMC Medicine. 11, 2013, p. 235, doi : 10.1186 / 1741-7015-11-235 .
- ↑ E. Albrecht, F. Norheim, B. Thiede, T. Holen, T. Ohashi, L. Scherin, S. Lee, J. Brenmoehl, S. Thomas, CA. Drevon, HP. Erickson, S. Maak: Irisin - a myth rather than an exercise-inducible myokine . Sci Rep 5, 8889 (2015), doi : 10.1038 / srep08889
- ^ S. Qiu, X. Cai, Z. Sun, U. Schumann, M. Zügel, JM Steinacker: Chronic Exercise Training and Circulating Irisin in Adults: A Meta-Analysis. In: Sports medicine (Auckland, NZ). Volume 45, Number 11, November 2015, pp. 1577–1588, doi : 10.1007 / s40279-014-0293-4 , PMID 26392122 .
- ↑ Jedrychowski, Mark P., Christiane D. Wrann, Joao A. Paulo, Kaitlyn K. Gerber, John Szpyt, Matthew M. Robinson, K. Sreekumaran Nair, Steven P. Gygi, and Bruce M. Spiegelman: Detection and Quantitation of Circulating Human Irisin by Tandem Mass Spectrometry. Cell Metabolism. 22, 2015, pp. 734-740. doi : 10.1016 / j.cmet.2015.08.001