The ubiquitin-modifying enzyme A20 restricts ubiquitination of the kinase RIPK3 and protects cells from necroptosis

Nat Immunol. 2015 Jun;16(6):618-27. doi: 10.1038/ni.3172. Epub 2015 May 4.


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.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis / genetics
  • Catalytic Domain / genetics
  • Cysteine Endopeptidases / genetics
  • Cysteine Endopeptidases / metabolism*
  • Fibroblasts / physiology*
  • Humans
  • Intracellular Signaling Peptides and Proteins / genetics
  • Intracellular Signaling Peptides and Proteins / metabolism*
  • Jurkat Cells
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Multiprotein Complexes / genetics
  • Necrosis / genetics
  • Protein Binding
  • Receptor-Interacting Protein Serine-Threonine Kinases / genetics
  • Receptor-Interacting Protein Serine-Threonine Kinases / metabolism*
  • T-Lymphocytes / physiology*
  • Tumor Necrosis Factor alpha-Induced Protein 3
  • Ubiquitination / genetics
  • Ubiquitins / metabolism


  • Intracellular Signaling Peptides and Proteins
  • Multiprotein Complexes
  • Ubiquitins
  • Receptor-Interacting Protein Serine-Threonine Kinases
  • Ripk1 protein, mouse
  • Ripk3 protein, mouse
  • Tumor Necrosis Factor alpha-Induced Protein 3
  • Cysteine Endopeptidases
  • Tnfaip3 protein, mouse