Description
Human cytomegalovirus(CMV) (human herpesvirus 5) glycoprotein B is a 907-amino acid glycoprotein encoded by the ORF of UL55. It is the most abundant component of the envelope with at least two defined neutralizing epitopes, a target of neutralizing antibodies and an essential replication component. The synthesized gB precursor matures into a 130-160 kDa glycoprotein by acquiring N-linked glycosylation modifications, and is cleaved by the cellular protease furin into two components, a 93-116 kDa N-terminal fragment and a 55 kDa C-terminal fragment linked by a disulfide-bond, which is presented on the viral envelope as well as on the surface of virus-infected cells as a covalently associated homodimer. gB plays important roles in HCMV entry, cell-cell spread of internal virions, and fusion of infected cells. It triggers penetration of cells and enhances the spread of infection in nonpolarized human fibroblasts. Theinteraction of gB with the non-heparin receptor CD209/DC-SIGN is the initiation of intracellular signaling and activation of the IFN-responsive pathway. In addition, gB is one envelope protein capable of heparin binding. It forms a physical association with host cell annexin II independent of the presence of calcium