Toll-like receptors and RNA helicases: two parallel ways to trigger antiviral responses.
The early detection by the host of invading microorganisms, including viruses, depends on a limited number of specific receptors that recognize pathogen-associated molecular patterns (PAMPs). A few of these PAMPs, including ssRNA and dsRNA, are recognized by Toll-like receptors (TLR)-7/8 and TLR3, respectively. Activation of an antiviral TLR-dependent signaling cascade leads to the activation of the key transcription factors IRF and NF-kappaB, which promote antiviral responses through induction of specific genes. Recently, a second system has been described, which relies on the cytoplasmic recognition of dsRNA by RNA helicases such as RIG-I. In this review, we discuss the mechanistic aspects of these important arms of the host innate response to dsRNA and a few viral strategies utilized to counteract them.
Meylan
Etienne
E
Department of Biochemistry, University of Lausanne, BIL Biomedical Research Center, Chemin des Boveresses 155, CH-1066 Epalinges, Switzerland.
Tschopp
Jürg
J
D000818:Animals; D003593:Cytoplasm / Q000378:metabolism; D000071457:DEAD Box Protein 58; D053487:DEAD-box RNA Helicases; D006801:Humans; D007113:Immunity, Innate; D000072640:Interferon-Induced Helicase, IFIH1; D008954:Models, Biological; D020365:RNA Helicases / Q000378:metabolism*; D012330:RNA, Double-Stranded / Q000378:metabolism; D012367:RNA, Viral / Q000378:metabolism*; D011971:Receptors, Immunologic; D015398:Signal Transduction; D051196:Toll-Like Receptor 3 / Q000378:metabolism; D051193:Toll-Like Receptors / Q000378:metabolism*; D014779:Virus Replication / Q000502:physiology
D012330:RNA, Double-Stranded; D012367:RNA, Viral; D011971:Receptors, Immunologic; D051196:Toll-Like Receptor 3; D051193:Toll-Like Receptors; C452820:RIGI protein, human; C452815:IFIH1 protein, human; D000071457:DEAD Box Protein 58; D053487:DEAD-box RNA Helicases; D000072640:Interferon-Induced Helicase, IFIH1; D020365:RNA Helicases