Autophagy is an evolutionary conserved mechanism for the sequestration and subsequent lysosomal degradation of discrete intracellular portions of eukaryotic cells, facilitating the removal of materials not degraded through the ubiquitin-proteasome pathway. In addition, autophagy plays important roles in innate and adaptive immune responses to pathogens.
Several viruses have develop ways to subvert the pathway for their own benefit in order to avoid the immune response or to increase their viral replication. Beclin-1 is an essential autophagy protein and constitutes the major target for manipulation of autophagy by viruses. For example, HHV-1 ICP34.5 binds to Beclin-1 and inhibits autophagosome formation. HIV and Influenza A virus use the same mechanism through Nef and M2 respectively, that also interact with and inhibit host Beclin-1.