Viruses catch a wave

Scientists know from looking at fixed cells that viruses frequently associate with filopodia and microvilli. Using video microscopy, Lehmann et al. (page 317) find that after a virus attaches to the filopodial membrane, it surfs down the plasma membrane toward the cell body. Entry into the cell occurs only after the virus has reached the base of the filopodium.

Retroviruses labeled with YFP initially contacted the filopodia of cells grown in culture. After a brief period of moving randomly on the filipodial surface, the viruses moved steadily in a retrograde fashion. Once the virus reached the cell body, the viral and host cell membranes fused, as detected by the diffusion of the fluorescently labeled envelope protein of the virus.

Vesicular stomatitis viruses, pH-dependent viruses that require endocytosis before membrane fusion, also surfed to the base...