Myxoma virus M013 protein antagonizes NF-κB and inflammasome pathways via distinct structural motifs

Rekha R. Garg, Cody B. Jackson, Masmudur M. Rahman, Amir R. Khan, Alfred S. Lewin, Grant McFadden

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


Amongthe repertoire of immunoregulatory proteins encoded by myxoma virus, M013 is a viral homologue of the viral pyrin domain-only protein (vPOP) family. In myeloid cells, M013 protein has been shown to inhibit both the inflammasome and NF-κB signaling pathways by direct binding to ASC1 and NF-κB1, respectively. In this study, a three-dimensional homology model of the M013 pyrin domain (PYD) was built based on similarities to known PYD structures. A distinctive feature of the deduced surface electrostatic map of the M013 PYD is the presence of a negatively region consisting of numerous aspartate and glutamate residues in close proximity. Single-site mutations of aspartate and glutamate residues reveal their role in interactions with ASC-1. The biological significance of charge complementarity in the M013-ASC-1 interaction was further confirmed by functional assays of caspase-1 activation and subsequent secretion of cytokines. M013 also has a unique 33-residue C-terminal tail that follows the N-terminal PYD, and it is enriched in positively charged residues. Deletion of the tail of M013 significantly inhibited the interactions between M013 and NF-κB1, thus compromising the ability of the viral protein to suppress the secretion of pro-inflammatory cytokines. These results demonstrate thatvPOPM013exploits distinct structural motifs to regulate both the inflammasome and NF-κB pathways.

Original languageEnglish (US)
Pages (from-to)8480-8489
Number of pages10
JournalJournal of Biological Chemistry
Issue number21
StatePublished - May 24 2019

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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