RhoA interacts with the fusion glycoprotein of respiratory syncytial virusand facilitates virus-induced syncytium formation

The fusion glycoprotein (F) of respiratory syncytial virus (RSV), which med iates membrane fusion and virus entry, was shown to bind RhoA, a small GTPa se, in yeast two-hybrid interaction studies. The interaction was confirmed in vivo by mammalian two-hybrid assay and in RSV-infected HEp-2 cells by co immunoprecipitation. Furthermore, the interaction of F with RhoA was confir med in vitro by enzyme-linked immunosorbent assay and biomolecular interact ion analysis. Yeast two-hybrid interaction studies with various deletion mu tants of F and with RhoA indicate that the key binding domains of these pro teins are contained within, or overlap, amino acids 146 to 155 and 67 to 11 0, respectively. The biological significance of this interaction eras studi ed in RSV-infected HEp-2 cells that were stably transfected to overexpress RhoA. There was a positive correlation between RhoA expression and RSV sync ytium formation, indicating that RhoA can facilitate RSV-induced syncytium formation.