Fig. 8. Otulin degradation boosts RIPA.

The model shows different steps of Otulin degradation triggered by RIPA. Otulin removes linear ubiquitin chains from IRF3 to inhibit the RIPA pathway and enhance viral replication. RIPA-activated caspase 3 leads to Otulin degradation by cleaving it at D31 position. The cleaved fragment is then K48-ubiquitinated by HOIP at K64 and K197, which leads to its proteasomal degradation.