Radical S-adenosyl methionine domain-containing protein 2 is commonly known as Viperin consisting of 43 kDa protein. which is a interferon inducible viral protein. Viperin expression is induced by IFN, IFNb, IFNg, human cytomegalovirus (HCMV) envelope protein, glycoprotein B (gB), etc. Viperin interaction with the viral protein vMIA results in viperin relocalization from the endoplasmic reticulum to the mitochondria. It interacts with the mitochondrial trifunctional protein which mediates beta-oxidation of fatty acids to generate ATP. Viperin promotes TLR7 and TLR9-dependent production of IFN-beta and also plays an important role in CD4+ T-cell activation and differentiation. Viperin is highly expressed in mouse and human brain.