Function of the respiratory syncytial virus small hydrophobic protein

Respiratory syncytial virus (RSV), a member of the Paramyxoviridae family, encodes a small hydrophobic (SH) protein of unknown function. Parainfluenza virus 5 (PIV5), a prototypical paramyxovirus, also encodes an SH protein, which inhibits tumor necrosis factor alpha (TNF-alpha) signaling. In this study, recombinant PIV5 viruses without their own SH but containing RSV SH (from RSV strain A2 or III) in its place (PIV5 Delta SH-RSV SH) and RSV lacking its own SH (RSV Delta SH) were generated and analyzed. The results indicate that the SH protein of RSV has a function similar to that of PIV5 SH and that it can inhibit TNF-alpha signaling.