Abstract:
Here, our structures and biochemistry reveal distinctive autoinhibition and activation mechanisms of the ARIH RBR E3 ligase ARIH2. It is activated upon super-assembly into an E3-E3 ubiquitin ligase complex with HIV-1 Vif-hijacked neddylated CUL5-RBX2 and APOBEC3-family substrates. Comparison with the neddylated CUL1-RBX1-ARIH1 superassembly shows a unique mode of activation and structural rearrangements mediated by NEDD8 in an allosteric manner.