The PACS-2 protein and trafficking motifs in CCHFV Gn and Gc cytoplasmic tails govern CCHFV assemblyViral and cellular determinants involved in CCHFV assembly

AbstractThe Crimean-Congo hemorrhagic fever virus (CCHFV) is a tick-borne bunyavirus that causes high mortality in humans with a wide geographic range. This enveloped virus has a tri-segmented negative or ambisense RNA genome that harbors two surface glycoproteins (GP), Gn and Gc. The maturation of the Gn/Gc glycoprotein precursor complex takes place in the ER and is completed through the secretion pathway. Here, we aimed at characterizing the trafficking network exploited by CCHFV GPs during the stages of virus assembly, envelopment, and/or egress. We identified putative membrane trafficking motifs in the cytoplasmic domains (CD) of CCHFV GPs and addressed how they can impact these late stages of the viral life cycle using infection assays, biochemical assays and confocal microscopy in virus-producing cells. Several of the identified CCHFV GP CD motifs could modulate GP transport through the retrograde trafficking network, impacting envelopment and secretion of infectious particles. Finally, we identified the phosphofurin acidic cluster sorting protein 2 (PACS-2) as a crucial host factor that contributes to CCHFV GPs trafficking required for assembly and release of viral particles.