Human metapneumovirus (HMPV) and respiratory syncytial virus (RSV) – major causes of serious respiratory disease – use a fusion (F) protein to bind to and infect target cells. Understanding how the F protein works could point to ways to disable it and prevent infection.
In previous studies, Reagan Cox, John Williams, M.D., associate professor of Pediatrics, and colleagues demonstrated that the HMPV F protein contained an “RGD” motif, which was recognized by an integrin receptor on the host cell surface.
In the Journal of Virology, they now report that the HMPV F protein binds to multiple types of RGD-binding integrin receptors and mediates virus binding and fusion, without a separate viral attachment protein. They showed that the F protein RGD motif is critical for infection (viruses without this motif were impaired). They also found that F-integrin binding was required for productive viral transcription (copying of the viral genome).
The results suggest a stepwise mechanism of HMPV cell entry mediated by the F protein through its interactions with cellular receptors, including RGD-binding integrins.
This research was supported by grants from the National Institute of Allergy and Infectious Diseases (AI073697, AI085062, AI007611), the National Cancer Institute (CA9682), and the National Center for Advancing Translational Sciences (RR024975) of the National Institutes of Health.
