RIG-I formed high molecular weight complexes in response to viral infection in HEK-293T cells and MEFs, but not in Ubc13 knockout MEFs, or in RIG-I knockout MEFs expressing RIG-I that cannot bind Ub, leading the authors to conclude that RIG-I oligomerization depends on binding to Lys63-linked poly-Ub generated by Ubc13. Here, RIGI is linked to viral infectious disease.