Ubiquitin-regulated recruitment of IkappaB kinase epsilon to the MAVS interferon signaling adapter.
Induction of the antiviral interferon response is initiated upon recognition of viral RNA structures by the RIG-I or Mda-5 DEX(D/H) helicases. A complex signaling cascade then converges at the mitochondrial adapter MAVS, culminating in the activation of the IRF and NF-kappaB transcription factors and the induction of interferon gene expression. We have previously shown that MAVS recruits IkappaB kinase epsilon (IKKepsilon) but not TBK-1 to the mitochondria following viral infection. Here we map the interaction of MAVS and IKKepsilon to the C-terminal region of MAVS and demonstrate that this interaction is ubiquitin dependent. MAVS is ubiquitinated following Sendai virus infection, and K63-linked ubiquitination of lysine 500 (K500) of MAVS mediates recruitment of IKKepsilon to the mitochondria. Real-time PCR analysis reveals that a K500R mutant of MAVS increases the mRNA level of several interferon-stimulated genes and correlates with increased NF-kappaB activation. Thus, recruitment of IKKepsilon to the mitochondria upon MAVS K500 ubiquitination plays a modulatory role in the cascade leading to NF-kappaB activation and expression of inflammatory and antiviral genes. These results provide further support for the differential role of IKKepsilon and TBK-1 in the RIG-I/Mda5 pathway.
Paz
Suzanne
S
Lady Davis Institute for Medical Research, Jewish General Hospital, 3755 Cote Ste. Catherine, Montreal, Quebec, Canada H3T 1E2.
Vilasco
Myriam
M
Arguello
Meztli
M
Sun
Qiang
Q
Lacoste
Judith
J
Nguyen
Thi Lien-Anh
TL
Zhao
Tiejun
T
Shestakova
Elena A
EA
Zaari
Scott
S
Bibeau-Poirier
Annie
A
Servant
Marc J
MJ
Lin
Rongtuan
R
Meurs
Eliane F
EF
Hiscott
John
J
D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D019556:COS Cells; D002460:Cell Line; D002522:Chlorocebus aethiops; D006367:HeLa Cells; D006801:Humans; D051550:I-kappa B Kinase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D016899:Interferon-beta / Q000378:metabolism; D008239:Lysine / Q000737:chemistry; D008928:Mitochondria / Q000378:metabolism; D016297:Mutagenesis, Site-Directed; D016328:NF-kappa B / Q000378:metabolism; D025941:Protein Interaction Mapping; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D029082:Sendai virus / Q000472:pathogenicity; D015398:Signal Transduction; D025801:Ubiquitin / Q000378:metabolism*
D048868:Adaptor Proteins, Signal Transducing; C505371:MAVS protein, human; D016328:NF-kappa B; D034741:RNA, Small Interfering; D011994:Recombinant Proteins; D025801:Ubiquitin; D016899:Interferon-beta; D017346:Protein Serine-Threonine Kinases; C403191:TBK1 protein, human; D051550:I-kappa B Kinase; D008239:Lysine