FNDC5 (fibronectin type III domain-containing protein 5) is a transmembrane protein precursor of irisin, a hormone-like peptide implicated in metabolic regulation, energy expenditure, and adipose tissue browning. Irisin is proteolytically cleaved from FNDC5 and secreted into circulation, primarily in response to exercise. Research on FNDC5/irisin has surged due to its potential role in obesity, diabetes, and metabolic disorders, driving demand for specific FNDC5 antibodies.
FNDC5 antibodies are critical tools for detecting the protein in various applications, including Western blotting, immunohistochemistry (IHC), and ELISA. They target specific epitopes within FNDC5’s structure, such as its N-terminal signal peptide, fibronectin III domain, or the irisin cleavage region. However, challenges persist due to FNDC5’s low basal expression levels and antibody specificity issues, which have led to inconsistencies across studies. Some antibodies may cross-react with unrelated proteins, necessitating rigorous validation using knockout controls.
Commercial FNDC5 antibodies are often raised in rabbits or mice against synthetic peptides or recombinant protein fragments. Their utility spans basic research—exploring FNDC5’s role in muscle-liver-adipose crosstalk—and clinical studies, such as correlating irisin levels with metabolic health. Recent work also investigates FNDC5’s neuroprotective effects and links to bone metabolism. As interest grows, optimizing antibody specificity remains pivotal for elucidating FNDC5’s physiological and therapeutic relevance.