Moreover, mex-3 RNA binding family member C (MEX3C, also known as RNF194) also triggers the linkage of Lys-63-linked polyubiquitin to Lys45, Lys99, and Lys169 within the CARDs of RIG-I to promote the immune response against viral infection (Figure 2) [98]. Here, RIGI is linked to viral infectious disease.