Respiratory syncytial virus (RSV) assembles on the surface of infected cells by forming filamentous particles bounded by a viral envelope that is derived from the host cell plasma membrane. Cholesterol-rich membrane microdomains (lipid rafts) are known to be involved in the viral infection cycle, including RSV morphogenesis. However, how the RSV envelope forms and the contribution of lipid raft components in this process is poorly understood. In their study on page 1037, Alexander Ludwig, Richard Sugrue and co-workers analyse the role of caveolae membrane pits and show that the main caveolae components, caveolin-1 and cavin-1, are recruited and incorporated into the RSV envelope. This occurs prior to RSV filament assembly, which takes place within caveolar membranes. The authors observe that caveolin-1 recruitment into the RSV envelope is dependent on the actin cytoskeleton, and involves an interaction with the viral membrane attachment glycoprotein. Furthermore, cavin-1 protein levels are increased and the stoichiometry of the caveolar coat complex altered upon virus infection. However, caveolae are not essential for RSV morphogenesis and cell-to-cell virus transmission in a cell culture model. Taken together, these results provide evidence that RSV exploits caveolae during viral filament assembly and suggest a post-assembly function for caveolae in the RSV life cycle.
- © 2017. Published by The Company of Biologists Ltd