HK-2 cells expressing FLAG-tagged FAR1 were infected with H1N1 (MOI=1) for 24 hous and then extract total protein. Anti-Flag magnetic beads were incubated with total protein for 4 h at 4℃ on a shaker, followed by adsorption of the magnetic beads to collect immunoprecipitated proteins using a magnetic stand. Subsequently, the beads were washed with PBS, and 20 μL of lysis buffer and 20 μL of protein loading buffer were added. The mixture was then placed in a boiling water bath for 10 min prior to conducting Western Blot analysis. The extracted immunoprecipitates were evaluated by mass spectrometry.