For instance, the two ubiquitin-ligases TRIM25 and RIPLET poly-ubiquitylate RIG-I with K63-linked ubiquitin chains during viral infection to enhance the formation of the RIG-I–MAVS complex (Gack et al, 2007; Gack et al, 2008; Oshiumi et al, 2009). Here, RIGI is linked to viral infectious disease.