The ubiquitin-modifying enzyme A20 restricts ubiquitination of the kinase RIPK3 and protects cells from necroptosis.
A20 is an anti-inflammatory protein linked to multiple human diseases; however, the mechanisms by which A20 prevents inflammatory disease are incompletely defined. We found that A20-deficient T cells and fibroblasts were susceptible to caspase-independent and kinase RIPK3-dependent necroptosis. Global deficiency in RIPK3 significantly restored the survival of A20-deficient mice. A20-deficient cells exhibited exaggerated formation of RIPK1-RIPK3 complexes. RIPK3 underwent physiological ubiquitination at Lys5 (K5), and this ubiquitination event supported the formation of RIPK1-RIPK3 complexes. Both the ubiquitination of RIPK3 and formation of the RIPK1-RIPK3 complex required the catalytic cysteine of A20's deubiquitinating motif. Our studies link A20 and the ubiquitination of RIPK3 to necroptotic cell death and suggest additional mechanisms by which A20 might prevent inflammatory disease.
Department of Medicine, University of California, San Francisco, San Francisco, California, USA.
Michio
M
Onizawa
Department of Medicine, University of California, San Francisco, San Francisco, California, USA.
Shigeru
S
Oshima
Department of Neurology, University of California, San Francisco, San Francisco, California, USA.
Ulf
U
Schulze-Topphoff
Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California, USA.
Juan A
JA
Oses-Prieto
Department of Medicine, University of California, San Francisco, San Francisco, California, USA.
Timothy
T
Lu
Department of Medicine, University of California, San Francisco, San Francisco, California, USA.
Rita
R
Tavares
Department of Neurology, University of California, San Francisco, San Francisco, California, USA.
Thomas
T
Prodhomme
Department of Medicine, University of California, San Francisco, San Francisco, California, USA.
Bao
B
Duong
Department of Medicine, University of California, San Francisco, San Francisco, California, USA.
Michael I
MI
Whang
Department of Medicine, University of California, San Francisco, San Francisco, California, USA.
Rommel
R
Advincula
Department of Medicine, University of California, San Francisco, San Francisco, California, USA.
Alex
A
Agelidis
Department of Medicine, University of California, San Francisco, San Francisco, California, USA.
Julio
J
Barrera
Program in Cellular and Molecular Medicine, Boston Children's Hospital, Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, USA.
Hao
H
Wu
Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California, USA.
Alma
A
Burlingame
Department of Medicine, University of California, San Francisco, San Francisco, California, USA.
Barbara A
BA
Malynn
Department of Neurology, University of California, San Francisco, San Francisco, California, USA.
Scott S
SS
Zamvil
Department of Medicine, University of California, San Francisco, San Francisco, California, USA.
Averil
A
Ma
D000818:Animals; D017209:Apoptosis / Q000235:genetics; D020134:Catalytic Domain / Q000235:genetics; D003546:Cysteine Endopeptidases / Q000235:genetics / Q000378:metabolism*; D005347:Fibroblasts / Q000502:physiology*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D019169:Jurkat Cells; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D046912:Multiprotein Complexes / Q000235:genetics; D009336:Necrosis / Q000235:genetics; D011485:Protein Binding; D053422:Receptor-Interacting Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D013601:T-Lymphocytes / Q000502:physiology*; D000072598:Tumor Necrosis Factor alpha-Induced Protein 3; D054875:Ubiquitination / Q000235:genetics; D014452:Ubiquitins / Q000378:metabolism
D047908:Intracellular Signaling Peptides and Proteins; D046912:Multiprotein Complexes; D014452:Ubiquitins; D053422:Receptor-Interacting Protein Serine-Threonine Kinases; C506251:Ripk1 protein, mouse; C485615:Ripk3 protein, mouse; D000072598:Tumor Necrosis Factor alpha-Induced Protein 3; D003546:Cysteine Endopeptidases; C513261:Tnfaip3 protein, mouse