The BM2 protein of influenza B virus interacts with p53 and inhibits its transcriptional and apoptotic activities.

The influenza virus integral membrane proteins BM2 (M2 of influenza B virus) and A/M2 (M2 of influenza A virus) functions as an ion channel, important for virus uncoating in endosomes of virus-infected cells and essential for viral replication. M2 ion channel activity is also required to stimulate NLRP3 inflammasome activation by perturbing ionic concentrations in the Golgi. In the present study, we have investigated further the interaction between BM2 and p53 to confirm our previous studies using yeast two-hybrid assays. The interaction between BM2 and p53 was confirmed by GST pull-down, co-immunoprecipitation assays, and confocal microscopy. Expression of BM2 results in down-regulation of p53 mRNA and protein expression in a dose-dependent manner. In addition, we demonstrated that exogenous expression of BM2 functionally blocked p53-mediated transcriptional activity and apoptosis by luciferase reporter assay and TUNEL assay, respectively. Together, the present results indicate that BM2 is able to functionally interact with p53, and provide valuable insights into the modulation of p53 functions by influenza virus.