FIG 3.

Generalized structure of an alphaherpesvirus cytoplasmic envelopment intermediate. The capsid (pink hexagon) is surrounded by an inner tegument (gray ovals) composed of UL36p/UL37p. This is the foundation for the attachment of the outer tegument subunits (shown in dark blue, cyan, orange, and dark gray), some of which interact with membrane-embedded envelope glycoproteins. There are multiple membrane proteins in the mature alphaherpesvirus envelope, but for clarity, only gB (purple), the gH/gL complex (yellow), and gD (pink) are shown (gD is absent from the alphaherpesvirus VZV). The ESCRT-III filament is assembled from CHMP subunits (green spheres) at the open bud neck. ESCRT-III will constrict to draw the membrane together, sealing the envelope and pinching the enveloped virus into the organellar lumen (light blue space). Constriction and ESCRT-III disassembly are catalyzed by the ATPase Vps4 (not shown).