Structural component of the virion that interacts with glycoprotein N. Acts as a class II fusion protein that is activated upon acidification and subsequent repositioning of the glycoprotein N. The glycoprotein protrusions are arranged on an icosahedral lattice, with T=12 triangulation. They are able to attach the virion to the host cell receptor CD209/DC-SIGN and to promote fusion of membranes with the late endosome after endocytosis of the virion