FIG 1.

The ESCRT apparatus and its utilization by enveloped viruses. The ESCRT-0 complex (STAM/HRS) is shown in brown, ESCRT-I (TSG101/MVB12/VPS37/VPS28) in red, and ESCRT-II (EAP30/EAP45/EAP20₂) in yellow. The ESCRT-III filament is shown as a polymer of CHMP2/3/4 subunits (green) capped by nucleating CHMP6 subunits (cyan). ESCRT-II complex EAP20 subunits nucleate filament assembly through the recruitment of CHMP6. ALIX is represented as a blue cylinder making contacts with ESCRT-I and extending its Bro1 domain (gray) to trigger CHMP4 polymerization. Nedd4 family members are shown in purple. Individual viruses or virus families in which one or more members have been reported to utilize Nedd4, ALIX, or an ESCRT complex during envelopment are indicated by boxes of the corresponding color.