PDGFRA and cytomegalovirus infection: Following binding of the HCMV trimer gH/gL/gO to its cellular receptor PDGFRα, gH/gL/gO activates the fusogenic activity of gB, thus inducing fusion of the viral envelope with the cell membrane using a pH-independent pathway, finally resulting in productive HCMV infection of fibroblasts (Figure 5).