Molecular mechanisms of viral and host-cell substrate recognition by HCV NS3/4A proteaseMolecular mechanisms of viral and host-cell substrate recognition by HCV NS3/4A protease

Structural highlights

3rc5 is a 2 chain structure with sequence from Hepatitis c virus subtype 1a. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Ligands:,
NonStd Res:
Gene:NS3 (Hepatitis C virus subtype 1a)
Resources:FirstGlance, OCA, RCSB, PDBsum

Function

[MAVS_HUMAN] Required for innate immune defense against viruses. Acts downstream of DDX58/RIG-I and IFIH1/MDA5, which detect intracellular dsRNA produced during viral replication, to coordinate pathways leading to the activation of NF-kappa-B, IRF3 and IRF7, and to the subsequent induction of antiviral cytokines such as IFN-beta and RANTES (CCL5). Peroxisomal and mitochondrial MAVS act sequentially to create an antiviral cellular state. Upon viral infection, peroxisomal MAVS induces the rapid interferon-independent expression of defense factors that provide short-term protection, whereas mitochondrial MAVS activates an interferon-dependent signaling pathway with delayed kinetics, which amplifies and stabilizes the antiviral response. May activate the same pathways following detection of extracellular dsRNA by TLR3. May protect cells from apoptosis.[1] [2] [3] [4] [5] [6]

Publication Abstract from PubMed

Hepatitis C NS3/4A protease is a prime therapeutic target responsible for cleaving the viral polyprotein at junctions 3-4A, 4A4B, 4B5A and 5A5B, and two host-cell adapter proteins of the innate immune response, TRIF and MAVS. In this study, NS3/4A crystal structures of both host-cell cleavage sites are determined and compared to the crystal structures of viral substrates. Two distinct protease conformations are observed and correlate with substrate specificity: (1) 3-4A, 4A4B, 5A5B and MAVS, which are processed more efficiently by the protease, form extensive electrostatic networks when in complex with the protease and (2) TRIF and 4B5A, which contain polyproline motifs in their full-length sequences, do not form electrostatic networks in their crystal complexes. These findings provide mechanistic insights into NS3/4A substrate recognition, which may assist in a more rational approach to inhibitor design in the face of the rapid acquisition of resistance.

Molecular mechanisms of viral and host-cell substrate recognition by HCV NS3/4A protease.,Romano KP, Laine JM, Deveau LM, Cao H, Massi F, Schiffer CA J Virol. 2011 Apr 20. PMID:21507982[7]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

  1. Seth RB, Sun L, Ea CK, Chen ZJ. Identification and characterization of MAVS, a mitochondrial antiviral signaling protein that activates NF-kappaB and IRF 3. Cell. 2005 Sep 9;122(5):669-82. PMID:16125763 doi:10.1016/j.cell.2005.08.012
  2. Xu LG, Wang YY, Han KJ, Li LY, Zhai Z, Shu HB. VISA is an adapter protein required for virus-triggered IFN-beta signaling. Mol Cell. 2005 Sep 16;19(6):727-40. PMID:16153868 doi:S1097-2765(05)01556-X
  3. Meylan E, Curran J, Hofmann K, Moradpour D, Binder M, Bartenschlager R, Tschopp J. Cardif is an adaptor protein in the RIG-I antiviral pathway and is targeted by hepatitis C virus. Nature. 2005 Oct 20;437(7062):1167-72. Epub 2005 Sep 21. PMID:16177806 doi:nature04193
  4. Kawai T, Takahashi K, Sato S, Coban C, Kumar H, Kato H, Ishii KJ, Takeuchi O, Akira S. IPS-1, an adaptor triggering RIG-I- and Mda5-mediated type I interferon induction. Nat Immunol. 2005 Oct;6(10):981-8. Epub 2005 Aug 28. PMID:16127453 doi:10.1038/ni1243
  5. Chiu YH, Macmillan JB, Chen ZJ. RNA polymerase III detects cytosolic DNA and induces type I interferons through the RIG-I pathway. Cell. 2009 Aug 7;138(3):576-91. doi: 10.1016/j.cell.2009.06.015. Epub 2009 Jul, 23. PMID:19631370 doi:10.1016/j.cell.2009.06.015
  6. Dixit E, Boulant S, Zhang Y, Lee AS, Odendall C, Shum B, Hacohen N, Chen ZJ, Whelan SP, Fransen M, Nibert ML, Superti-Furga G, Kagan JC. Peroxisomes are signaling platforms for antiviral innate immunity. Cell. 2010 May 14;141(4):668-81. doi: 10.1016/j.cell.2010.04.018. Epub 2010 May, 6. PMID:20451243 doi:10.1016/j.cell.2010.04.018
  7. Romano KP, Laine JM, Deveau LM, Cao H, Massi F, Schiffer CA. Molecular mechanisms of viral and host-cell substrate recognition by HCV NS3/4A protease. J Virol. 2011 Apr 20. PMID:21507982 doi:10.1128/JVI.00377-11

3rc5, resolution 1.60Å

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