A genome-wide base-editing screen uncovers a pivotal role of paxillin δ ubiquitination in influenza virus infection

Dissecting host factors critical for viral infection and understanding their mechanisms of action is critical for identifying drug targets. Here, we leverage a genome-wide CRISPR base-editing screen to identify functional lysine residues in host factors required for influenza A virus (IAV) replication. Multiple host genes, including GSTM4, FLNC, HMGB1, ZNF236, GRIP1, and PXN, along with regulatory lysine codons, are identified. Among these, paxillin (encoded by PXN) is identified as an important host entry factor. Depletion of paxillin significantly reduces IAV infection in both cell cultures and mice. Further analysis suggests that the δ isoform of paxillin, rather than the canonical β isoform, plays the key role. Additionally, our data indicate that lysine 68 of paxillin δ undergoes K6-linked ubiquitination and regulates influenza virus replication via modulating endosome-dependent viral entry. These observations contribute to understanding how influenza viruses interact with host factors and may inform therapeutic development.