Coronavirus envelope glycoprotein assembly complexes.

Protein:protein interactions, and their subcellular localization, play important roles in coronavirus assembly. In this study, we have identified similar envelope glycoprotein complexes that are present in mouse hepatitis coronavirus A59 (MHV-A59) and bovine coronavirus (BCV) infected cells. Complexes consisting of the spike (S) and membrane (M) proteins were identified in cells infected with MHV-A59 or BCV. Kinetic analyses demonstrated that S and M quickly associated after translation, and suggested that both initially interacted in a pre-Golgi site. In addition, the hemagglutinin esterase (HE) was identified as part of a complex with M and S in BCV infected cells. Taken together, our data indicate that similar glycoprotein complexes are present in cells infected with two different coronaviruses, and thus likely represent important prerequisite complexes involved in virus assembly.