4hbe

Structural highlights

Function

POLS_RUBVM Capsid protein interacts with genomic RNA and assembles into icosaedric core particles. The resulting nucleocapsid eventually associates with the cytoplasmic domain of E2 at the cell membrane, leading to budding and formation of mature virions. Phosphorylation negatively regulates RNA-binding activity, possibly delaying virion assembly during the viral replication phase. Capsid protein dimerizes and becomes disulfide-linked in the virion, but this interaction seems not to be important for its biological function. Modulates genomic RNA replication. Modulates subgenomic RNA synthesis by interacting with human C1QBP/SF2P32. Induces both perinuclear clustering of mitochondria and the formation of electron-dense intermitochondrial plaques, both hallmarks of rubella virus infected cells. Induces apoptosis when expressed in transfected cells. E2 envelope glycoprotein is responsible for viral attachment to target host cell, by binding to the cell receptor. Its transport to the plasma membrane depends on interaction with E1 protein. E1 envelope glycoprotein is a class II viral fusion protein. Fusion activity is inactive as long as E1 is bound to E2 in mature virion. After virus attachment to target cell and clathrin-mediated endocytosis, acidification of the endosome would induce dissociation of E1/E2 heterodimer and concomitant trimerization of the E1 subunits. This E1 homotrimer is fusion active, and promotes release of viral nucleocapsid in cytoplasm after endosome and viral membrane fusion (By similarity). E1 cytoplasmic tail modulates virus release, and the tyrosines residues are critical for this function.

References

1. ↑ Mangala Prasad V, Willows SD, Fokine A, Battisti AJ, Sun S, Plevka P, Hobman TC, Rossmann MG. Rubella virus capsid protein structure and its role in virus assembly and infection. Proc Natl Acad Sci U S A. 2013 Nov 26. PMID:24282305 doi:http://dx.doi.org/10.1073/pnas.1316681110