. "ISG15 negatively regulates the scaffold protein filamin B. In response to type I IFNs, filamin B recruits RAC1, MEKK1, and MKK4, enhancing their sequential activation and thereby promoting JNK activation and apoptosis. ISGylation of filamin B leads to the disassociation of RAC1, MEKK1, and MKK4 from the scaffold, preventing type I IFN dependent JNK activation and apoptosis. It has been suggested that this inhibition of apoptosis may protect uninfected bystander cells from IFN-mediated apoptosis (Jeon et al, 2009)."^^ . . . . . . . . .