Format

Send to

Choose Destination
Proc Natl Acad Sci U S A. 2007 Aug 28;104(35):14050-5. Epub 2007 Aug 20.

The Atg5 Atg12 conjugate associates with innate antiviral immune responses.

Author information

1
Department of Molecular Biodefense Research, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan.

Abstract

Autophagy is an essential process for physiological homeostasis, but its role in viral infection is only beginning to be elucidated. We show here that the Atg5-Atg12 conjugate, a key regulator of the autophagic process, plays an important role in innate antiviral immune responses. Atg5-deficient mouse embryonic fibroblasts (MEFs) were resistant to vesicular stomatitis virus replication, which was largely due to hyperproduction of type I interferons in response to immunostimulatory RNA (isRNA), such as virus-derived, double-stranded, or 5'-phosphorylated RNA. Similar hyperresponse to isRNA was also observed in Atg7-deficient MEFs, in which Atg5-Atg12 conjugation is impaired. Overexpression of Atg5 or Atg12 resulted in Atg5-Atg12 conjugate formation and suppression of isRNA-mediated signaling. Molecular interaction studies indicated that the Atg5-Atg12 conjugate negatively regulates the type I IFN production pathway by direct association with the retinoic acid-inducible gene I (RIG-I) and IFN-beta promoter stimulator 1 (IPS-1) through the caspase recruitment domains (CARDs). Thus, in contrast to its role in promoting the bactericidal process, a component of the autophagic machinery appears to block innate antiviral immune responses, thereby contributing to RNA virus replication in host cells.

PMID:
17709747
PMCID:
PMC1955809
DOI:
10.1073/pnas.0704014104
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for HighWire Icon for PubMed Central
Loading ...
Support Center