Inhibition of Viral Fusion by Interferon-Induced Transmembrane Proteins

Abstract

Interferon-induced transmembrane proteins (IFITMs) are small type II membrane proteins exhibiting a remarkably broad activity against diverse enveloped viruses. Expression of IFITMs blocks infection by inhibiting virus-cell fusion, however, the mechanism by which these proteins interfere with virus entry remains unclear. Using single virus tracking in living cells, we have demonstrated that IFITM3, the member of IFITM family that is localized to endosomes, is concentrated at the sites of the influenza virus entry and blocks viral fusion with endosomes at a hemifusion intermediate.