MDA5 (melanoma differentiation-associated protein 5) is a RIG-I-like receptordsRNAhelicaseenzyme that is encoded by the IFIH1gene in humans.[5] MDA5 is part of the RIG-I-like receptor (RLR) family, which also includes RIG-I and LGP2, and functions as a pattern recognition receptor capable of detecting viruses. It is generally believed that MDA5 recognizes double stranded RNA (dsRNA) over 2000nts in length,[6] however it has been shown that whilst MDA5 can detect and bind to cytoplasmic dsRNA, it is also activated by a high molecular weight RNA complex composed of ssRNA and dsRNA.[7] For many viruses, effective MDA5-mediated antiviral responses are dependent on functionally active LGP2.[8] The signaling cascades in MDA5 is initiated via CARD domain.[9] Some observations made in cancer cells show that MDA5 also interacts with cellular RNA is able to induce an autoinflammatory response.[10]
^Takeuchi O, Akira S (February 2008). "MDA5/RIG-I and virus recognition". Current Opinion in Immunology. 20 (1): 17–22. doi:10.1016/j.coi.2008.01.002. PMID18272355.