Investigating the Role of Rab25 in Influenza A Virus Infection

The intracellular trafficking of Influenza A Virus (IAV) genome segments is a critical determinant of viral assembly and replication. As a segmented virus that replicates in the nucleus, IAV must transport its viral ribonucleoprotein (vRNP) complexes to the site of budding at the plasma membrane using cellular trafficking machinery. Prior work has established that transport of the vRNPs requires the vesicular GTPase Rab11A, which binds directly to the PB2 component of the polymerase complex located on each vRNP. While previous studies have established that Rab11A and Rab11B are required for efficient viral replication, there is no data available on the role of the third member of the Rab11 family (Rab25/Rab11C) in influenza virus infection. While Rab25 is not expressed in A549 cells, we observe high levels of expression in the primary targets of influenza infection (especially in club cells). In stable cell lines expressing GFP-Rab25, we observe specific colocalization with nucleoprotein (NP) during late time points in infection, as well as a change in the distribution of Rab25 upon infection. Analysis of Rab25 movement in live cells infected with IAV reveals that infection significantly slows the distance travelled by Rab25 (also observed in Rab11A) vesicles, with a redistribution of vesicles to the cell periphery. As Rab25 shares a high degree of conservation with Rab11A in the PB2 binding region and is predicted to share/compete with the motor proteins utilized by Rab11A, this cellular protein is likely to have a consequential effect on influenza infection as either pro- or anti- viral factor.