Analysis of proteins proximal to epsin 1 in A549 cells during entry of influenza A virus

Influenza A viruses (IAVs) are respiratory pathogens that represent a global concern due to their ability to cause seasonal epidemics and sporadic pandemics in the human population. Thus, a comprehensive understanding of IAV biology is essential in order to design effective antivirals. It is well established that entry of most IAVs begins through binding to cell surface sialic acid, however the identity of receptors that mediate virus internalization remains unclear. Here, we performed TurboID-based proximity labelling centered on epsin 1, a protein required for clathrin-mediated endocytosis of IAV, to uncover internalization receptors. By performing affinity-based purification of biotinylated proteins coupled to mass spectrometry, we identified 34 proteins proximal to epsin 1 during IAV infection. Therein we found 11 high-confidence STRING interactors for epsin 1 and 3 putative pro-viral host factors for IAV infection, validating our approach.