RSV F

Respiratory syncytial virus (RSV) is a major pathogen in infants and young children worldwide, causing bronchiolitis and pneumonia in 1% to 5% of this population. RSV also causes substantial morbidity and mortality among the elderly. RSV F is a type I viral fusion protein responsible for driving fusion of the viral envelope with host cell membranes during viral entry. It is capable of causing membrane fusion and initiating virus infection in immortalized, cultured cells in the absence of its attachment G glycoprotein. The RSV F protein expressed in non-polarized cultured cells is reported to cause cell-cell fusion at neutral pH, leading to the characteristic syncytia or multinucleated giant cells.

The RSV F protein is a trimer. Each monomer is produced in a precursor, F0, form
that is modified by N-linked glycans. During passage through the Golgi apparatus, these glycans mature and the protein is cleaved by a furin-like protease in two positions, releasing a 27-amino-acid peptide (pep27) with attached glycans. The resulting F protein is composed of the N-terminal F2 protein linked by one, and probably two, disulfide bonds to the F1 transmembrane protein.