ADP Ribosylation Factor Like Protein 16 (ARL16)

ARL16, as a protein that interacts with RIG-I. Overexpression of ARL16, but not its homologous proteins ARL1 and ARF1, inhibited RIG-I-mediated downstream signaling and antiviral activity. Knockdown of endogenous ARL16 by RNAi potentiated Sendai virus-induced IFN-β expression and vesicular stomatitis virus replication. ARL16 interacted with the C-terminal domain (CTD) of RIG-I to suppress the association between RIG-I and RNA. ARL16 (T37N) and ARL16Δ45-54, which were restricted to the GTP-disassociated form, did not interact with RIG-I and also lost the inhibitory function. Endogenous ARL16 changes to GTP-binding status upon viral infection and binds with the RIG-I CTD to negatively control its signaling activity. ARL16 inhibits RIG-I by binding with its C-terminal domain in a GTP-dependent manner.