The mitochondrial ubiquitin ligase MARCH5 resolves MAVS aggregates during antiviral signalling

Nat Commun. 2015 Aug 6;6:7910. doi: 10.1038/ncomms8910.

Abstract

Mitochondria serve as platforms for innate immunity. The mitochondrial antiviral signalling (MAVS) protein forms aggregates that elicit robust type-I interferon induction on viral infection, but persistent MAVS signalling leads to host immunopathology; it remains unknown how these signalling aggregates are resolved. Here we identify the mitochondria-resident E3 ligase, MARCH5, as a negative regulator of MAVS aggregates. March5(+/-) mice and MARCH5-deficient immune cells exhibit low viral replication and elevated type-I interferon responses to RNA viruses. MARCH5 binds MAVS only during viral stimulation when MAVS forms aggregates, and these interactions require the RING domain of MARCH5 and the CARD domain of MAVS. MARCH5, but not its RING mutant (MARCH5(H43W)), reduces the level of MAVS aggregates. MARCH5 transfers ubiquitin to Lys7 and Lys500 of MAVS and promotes its proteasome-mediated degradation. Our results indicate that MARCH5 modulates MAVS-mediated antiviral signalling, preventing excessive immune reactions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / metabolism*
  • Animals
  • HEK293 Cells
  • Humans
  • Immunity, Innate
  • Interferon Type I / metabolism
  • Membrane Proteins / metabolism*
  • Mice, Inbred C57BL
  • Mitochondria / enzymology
  • Mitochondrial Proteins / metabolism*
  • RNA Virus Infections / immunology*
  • Ubiquitin / metabolism
  • Ubiquitin-Protein Ligases / metabolism*

Substances

  • Adaptor Proteins, Signal Transducing
  • IPS-1 protein, mouse
  • Interferon Type I
  • MAVS protein, human
  • Membrane Proteins
  • Mitochondrial Proteins
  • Ubiquitin
  • MARCH5 protein, mouse
  • MARCHF5 protein, human
  • Ubiquitin-Protein Ligases