Hepatitis B surface antigen assembles in a post-ER, pre-Golgi compartment

NVELOPED animal viruses have been major tools in the characterization of the secretory pathway and in advancing our understanding of the mechanisms of protein sorting. Frequently, particular features of the pathways of protein traffic are exploited in the maturation pathways of different viruses so that a study of virus assembly leads to unexpected rewards in terms of an understanding of intracellular transport. This paper presents a study of the assembly of the lipoprotein particle formed by the transmembrane glycoprotein of hepatitis B virus. This particle has the unusual feature of being stabilized by extensive intermolecutax crosslinks and here we show that this reflects its assembly in an intermediate compartment between the ER and the Golgi.