Fig. 6. The interplay between autophagy and enterovirus replication is dynamic, selective, and sequential.

This model illustrates how remodeled cytoplasmic membranes act as a platform for viral RNA replication and as a production line for virion assembly. (1) Capsid proteins, produced as part of the membrane-associated viral polyprotein, assemble on the replication membrane to the point of half-capsid intermediate. The antiviral drug Hydantoin leads to premature capsid release from membranes. Away from the replication membrane, capsids cannot be loaded with RNA. (2) The assembly pauses at the long-lived half-capsid intermediate that carries out the “late proofreading” resulting in exclusive incorporation of newly synthesized membrane-associated viral RNA³⁰. The inhibition of VPS34 stalls the assembly at the half-capsid checkpoint, possibly by reducing RNA replication. (3) RNA-loading of the capsid leads to the formation of complete virions tethered to the replication membrane. (4) Phagophores selectively package RNA-loaded virions while excluding empty capsids. The virion-containing class of phagophores is distinct from a second class of phagophores containing bundles of protein filaments. (5) A balance between ULK1-induced canonical autophagy and virus-induced proviral autophagy regulates the level of virion production. Inhibition of remaining ULK1 activity by MRT68921 further increases virion production. Created with BioRender.com.