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

Our results also do not directly address the state of the HBsAg in the virion. During viral infection, the bulk of HBsAg follows the pathway which we have described in this paper but a fraction of it forms the envelope of budding virions. Budding of the virion requires interaction with the capsid, or core protein of this DNA virus in a manner which Figure 10 . A model for HBsAg particle maturation in the cell. Newly synthesized HBsAg is translocated into the ER lumen (ER) where disulphide-linked dimers form rapidly in the presence of PDI. Dimers are then transported to an ER-Golgi intermediate compartment (IC), where HBsAg forms higher oligomers and assembles into extensively disulphide crosslinked particles. This assembly process is the rate limiting step in the I-IBsAg particle secretion. The mature particles are then transported rapidly through the Golgi and are secreted. The depiction of the dimer and oligomer crosslinks should be interpreted schematically.