A Role for IFITM Proteins in Restriction of Mycobacterium tuberculosis Infection

Ranjbar, Shahin; Haridas, Viraga; Jasenosky, Luke D.; Falvo, James V.; Goldfeld, Anne E.

Virus restriction by individual IFITMs depends both on cell type and the intracellular location of each family member. For example, HIV, which undergoes viral envelope-cell membrane fusion at the cell surface or within early endosomes, is more restricted by IFITM1 (Lu et al., 2011) , while influenza A virus, which requires pH-dependent changes in envelope glycoprotein conformation for viral fusion at late endosomes/lysosomes, is more restricted by IFITM2/3 (Brass et al., 2009; Desai et al., 2014; Feeley et al., 2011; John et al., 2013) . IFITMs appear to block viral infection by reducing host membrane fluidity at sites of viral fusion through self-interactions and/or interactions with nearby transmembrane proteins, leading to inhibition of viral fusion pore formation and increased trafficking of trapped viruses to the lysosome for degradation (Desai et al., 2014; Lin et al., 2013) .