Comparative analysis reveals adaptive evolution of bat IFITMs and a novel antiviral determinant

Abstract

doi: bioRxiv preprint 65 required for the antiviral activity of both IFITM3 and IFITM1 [9]. The subcellular localization of 66 IFITMs is a key determinant of their antiviral profile. When expressed singly, IFITM3 and IFITM2 67 preferentially localize to early and late endosomes and lysosomes, and restrict viruses that enter via 68 these endo-lysosomal compartments. In contrast, IFITM1 primarily localizes at the cell surface and 69 can restrict viruses that enter through the plasma membrane [11-14]. Indeed, mutants of IFITM3 70 that lack an N-terminal endocytic sorting motif 20 YEML 23 localize to the plasma membrane and lose 71 their ability to inhibit influenza A virus (IAV), alphavirus and coronavirus infection by endosomal 72 routes [14-18]. 73 74 Studies focusing on IFITM3 restriction of IAV and Semliki Forest Virus (SFV) indicate that virus 75 internalization is unaffected by IFITM3 expression and, for SFV at least, the viral envelope 76 . CC-BY-NC-ND 4.0 International license author/funder. It is made available under a The copyright holder for this preprint (which was not peer-reviewed) is the . https://doi.org/10.1101/737841 doi: bioRxiv preprint 109 knockout mice show enhanced morbidity after infection with IAV, alphaviruses and flaviviruses [33-110 .