Small molecule inhibitors reveal an indispensable scaffolding role of RIPK2 in NOD2 signaling

EMBO J. 2018 Sep 3;37(17):e99372. doi: 10.15252/embj.201899372. Epub 2018 Jul 19.

Abstract

RIPK2 mediates inflammatory signaling by the bacteria-sensing receptors NOD1 and NOD2. Kinase inhibitors targeting RIPK2 are a proposed strategy to ameliorate NOD-mediated pathologies. Here, we reveal that RIPK2 kinase activity is dispensable for NOD2 inflammatory signaling and show that RIPK2 inhibitors function instead by antagonizing XIAP-binding and XIAP-mediated ubiquitination of RIPK2. We map the XIAP binding site on RIPK2 to the loop between β2 and β3 of the N-lobe of the kinase, which is in close proximity to the ATP-binding pocket. Through characterization of a new series of ATP pocket-binding RIPK2 inhibitors, we identify the molecular features that determine their inhibition of both the RIPK2-XIAP interaction, and of cellular and in vivoNOD2 signaling. Our study exemplifies how targeting of the ATP-binding pocket in RIPK2 can be exploited to interfere with the RIPK2-XIAP interaction for modulation of NOD signaling.

Keywords: XIAP; NOD2 signaling; RIPK2; kinase inhibitor; ubiquitin.

Publication types

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

MeSH terms

  • Animals
  • Cell Line, Tumor
  • Female
  • Humans
  • Inhibitor of Apoptosis Proteins / genetics
  • Inhibitor of Apoptosis Proteins / metabolism
  • Mice
  • Nod2 Signaling Adaptor Protein / genetics
  • Nod2 Signaling Adaptor Protein / metabolism*
  • Protein Kinase Inhibitors / pharmacology*
  • Receptor-Interacting Protein Serine-Threonine Kinase 2 / antagonists & inhibitors*
  • Receptor-Interacting Protein Serine-Threonine Kinase 2 / genetics
  • Receptor-Interacting Protein Serine-Threonine Kinase 2 / metabolism
  • Receptor-Interacting Protein Serine-Threonine Kinases / antagonists & inhibitors*
  • Receptor-Interacting Protein Serine-Threonine Kinases / genetics
  • Receptor-Interacting Protein Serine-Threonine Kinases / metabolism
  • Signal Transduction / drug effects*
  • Signal Transduction / genetics
  • X-Linked Inhibitor of Apoptosis Protein / genetics
  • X-Linked Inhibitor of Apoptosis Protein / metabolism

Substances

  • Birc4 protein, mouse
  • Inhibitor of Apoptosis Proteins
  • NOD2 protein, human
  • Nod2 Signaling Adaptor Protein
  • Nod2 protein, mouse
  • Protein Kinase Inhibitors
  • X-Linked Inhibitor of Apoptosis Protein
  • XIAP protein, human
  • RIPK2 protein, human
  • Receptor-Interacting Protein Serine-Threonine Kinase 2
  • Receptor-Interacting Protein Serine-Threonine Kinases
  • Ripk2 protein, mouse