PARP5A and RNF146 phase separation restrains RIPK1-dependent necroptosis

Mol Cell. 2024 Mar 7;84(5):938-954.e8. doi: 10.1016/j.molcel.2023.12.041. Epub 2024 Jan 24.


Phase separation is a vital mechanism that mediates the formation of biomolecular condensates and their functions. Necroptosis is a lytic form of programmed cell death mediated by RIPK1, RIPK3, and MLKL downstream of TNFR1 and has been implicated in mediating many human diseases. However, whether necroptosis is regulated by phase separation is not yet known. Here, we show that upon the induction of necroptosis and recruitment by the adaptor protein TAX1BP1, PARP5A and its binding partner RNF146 form liquid-like condensates by multivalent interactions to perform poly ADP-ribosylation (PARylation) and PARylation-dependent ubiquitination (PARdU) of activated RIPK1 in mouse embryonic fibroblasts. We show that PARdU predominantly occurs on the K376 residue of mouse RIPK1, which promotes proteasomal degradation of kinase-activated RIPK1 to restrain necroptosis. Our data demonstrate that PARdU on K376 of mouse RIPK1 provides an alternative cell death checkpoint mediated by phase separation-dependent control of necroptosis by PARP5A and RNF146.

Keywords: PARP5A; PARylation; RIPK1; RNF146; necroptosis; phase separation; ubiquitination.

MeSH terms

  • Animals
  • Apoptosis / physiology
  • Cell Death
  • Fibroblasts / metabolism
  • Mice
  • Necroptosis* / genetics
  • Phase Separation*
  • Receptor-Interacting Protein Serine-Threonine Kinases / genetics
  • Receptor-Interacting Protein Serine-Threonine Kinases / metabolism
  • Ubiquitin-Protein Ligases / genetics
  • Ubiquitin-Protein Ligases / metabolism


  • Receptor-Interacting Protein Serine-Threonine Kinases
  • Ubiquitin-Protein Ligases
  • Rnf146 protein, mouse
  • Ripk1 protein, mouse