title: PKR-dependent autophagic degradation of herpes simplex virus type 1.
abstract: The lysosomal pathway of autophagy is the major catabolic mechanism for degrading long-lived cellular proteins and cytoplasmic organelles. Recent studies have also shown that autophagy (xenophagy) may be used to degrade bacterial pathogens that invade intracellularly. However, it is not yet known whether xenophagy is a mechanism for degrading viruses. Previously, we showed that autophagy induction requires the antiviral eIF2alpha kinase signaling pathway (including PKR and eIF2alpha) and that this function of eIF2alpha kinase signaling is antagonized by the herpes simplex virus (HSV-1) neurovirulence gene product, ICP34.5. Here, we show quantitative morphologic evidence of PKR-dependent xenophagic degradation of herpes simplex virions and biochemical evidence of PKR and eIF2alpha-dependent degradation of HSV-1 proteins, both of which are blocked by ICP34.5. Together, these findings indicate that xenophagy degrades HSV-1 and that this cellular function is antagonized by the HSV-1 neurovirulence gene product, ICP34.5. Thus, autophagy-related pathways are involved in degrading not only cellular constituents and intracellular bacteria, but also viruses.
authors.affiliation: Department of Medicine, Columbia University College of Physicians & Surgeons, New York, New York, USA.
authors.forename: Zsolt
authors.initials: Z
authors.lastname: Tallóczy
authors.forename: Herbert W
authors.initials: HW
authors.lastname: Virgin
authors.forename: Beth
authors.initials: B
authors.lastname: Levine
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000494:pharmacology; D001343:Autophagy / Q000187:drug effects / Q000235:genetics; D002478:Cells, Cultured; D005347:Fibroblasts / Q000201:enzymology / Q000648:ultrastructure / Q000821:virology; D018259:Herpesvirus 1, Human / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D014764:Viral Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D019892:eIF-2 Kinase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*
chemical_list: D000914:Antibodies, Viral; D047428:Protein Kinase Inhibitors; D014764:Viral Proteins; C066469:gamma 34.5 protein, Human herpesvirus 1; D019892:eIF-2 Kinase