FIG 1.

Vps4A-EQ is expected to differentially perturb the microtubule-dependent trafficking of naked and enveloped alphaherpesvirus capsids. The assembly of enveloped trafficking particles (steps 1 to 3) requires that cytoplasmic capsids (black discs) engage organelles (step 1) to undergo ESCRT-mediated envelopment (step 2). Vps4 (gray rings)-driven scission (step 3) then generates enveloped, organelle-bounded virions that subsequently traffic along microtubules. In this model, Vps4A-EQ-arrested envelopment (step 3) occurs before the generation of motile particles. Alternatively, for naked capsid trafficking prior to envelopment (steps a to c), cytoplasmic capsids first travel along microtubules (step a) to reach the site at which they undergo ESCRT-mediated budding (step b) and scission (step c). In this case, Vps4A-EQ blocks envelopment (step c) after microtubule-dependent motility has occurred.