Autophagy and viruses: adversaries or allies?

The autophagy pathway is an essential component of host defense against viral infection, orchestrating pathogen degradation (xenophagy), innate immune signaling, and certain aspects of adaptive immunity. Single autophagy proteins or cassettes of the core autophagy machinery can also function as antiviral factors independently of the canonical autophagy pathway. Moreover, to survive and propagate within the host, viruses have evolved a variety of strategies to evade autophagic attack and manipulate the autophagy machinery for their own benefit. This review summarizes recent advances in understanding the antiviral and proviral roles of autophagy and previously unappreciated autophagy-independent functions of autophagy-related genes.