Interaction between the respiratory syncytial virus G glycoprotein cytoplasmic domain and the matrix protein

1 Department of Respiratory and Sleep Medicine, Monash Medical Centre, 246 Clayton Road, Clayton 3168, Australia 2 Departments of Microbiology and Medicine, Monash University, Clayton, Australia 3 Department of Environmental Biology, RMIT University, Melbourne, Australia 4 Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Australia 5 Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, MA, USA Correspondence Reena Ghildyal reena.ghildyal{at}med.monash.edu.au Paramyxovirus assembly at the cell membrane requires the movement of viral components to budding sites and envelopment of nucleocapsids by cellular membranes containing viral glycoproteins, facilitated by interactions with the matrix protein. The specific protein interactions during assembly of respiratory syncytial virus (RSV) are unknown. Here, the postulated interaction between the RSV matrix protein (M) and G glycoprotein (G) was investigated. Partial co-localization of M with G was demonstrated, but not with a truncated variant lacking the cytoplasmic domain and one-third of the transmembrane domain, in cells infected with recombinant RSV or transfected to express G and M. A series of G mutants was constructed with progressively truncated or modified cytoplasmic domains. Data from co-expression in cells and a cell-free binding assay showed that the N-terminal aa 2–6 of G play a key role in G–M interaction, with serine at position 2 and aspartate at position 6 playing key roles. Present address: Department of Biochemistry and Molecular Biology, The Pennsylvania State University, PA, USA.