title: Engagement of nucleotide-binding oligomerization domain-containing protein 1 (NOD1) by receptor-interacting protein 2 (RIP2) is insufficient for signal transduction.
abstract: Following activation, the cytoplasmic pattern recognition receptor nucleotide-binding oligomerization domain-containing protein 1 (NOD1) interacts with its adaptor protein receptor-interacting protein 2 (RIP2) to propagate immune signaling and initiate a proinflammatory immune response. This interaction is mediated by the caspase recruitment domain (CARD) of both proteins. Polymorphisms in immune proteins can affect receptor function and predispose individuals to specific autoinflammatory disorders. In this report, we show that mutations in helix 2 of the CARD of NOD1 disrupted receptor function but did not interfere with RIP2 interaction. In particular, N43S, a rare polymorphism, resulted in receptor dysfunction despite retaining normal cellular localization, protein folding, and an ability to interact with RIP2. Mutation of Asn-43 resulted in an increased tendency to form dimers, which we propose is the source of this dysfunction. We also demonstrate that mutation of Lys-443 and Tyr-474 in RIP2 disrupted the interaction with NOD1. Mapping the key residues involved in the interaction between NOD1 and RIP2 to the known structures of CARD complexes revealed the likely involvement of both type I and type III interfaces in the NOD1·RIP2 complex. Overall we demonstrate that the NOD1-RIP2 signaling axis is more complex than previously assumed, that simple engagement of RIP2 is insufficient to mediate signaling, and that the interaction between NOD1 and RIP2 constitutes multiple CARD-CARD interfaces.
authors: Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, United Kingdom.
authors: Sophie
authors: S
authors: Mayle
authors: Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, United Kingdom.
authors: Joseph P
authors: JP
authors: Boyle
authors: Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, United Kingdom.
authors: Eiki
authors: E
authors: Sekine
authors: Institute for Medical Microbiology, Immunology and Hygiene, University of Cologne, Goldenfelsstrasse 19-21, 50935 Köln, Germany, and.
authors: Birte
authors: B
authors: Zurek
authors: Institute for Medical Microbiology, Immunology and Hygiene, University of Cologne, Goldenfelsstrasse 19-21, 50935 Köln, Germany, and.
authors: Thomas A
authors: TA
authors: Kufer
authors: Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, United Kingdom,; Department of Veterinary Medicine, University of Cambridge, Cambridge CB3 0ES, United Kingdom. Electronic address: tpm22@cam.ac.uk.
authors: Tom P
authors: TP
authors: Monie
mesh_terms: D057809:HEK293 Cells; D006801:Humans; D009154:Mutation; D053474:Nod1 Signaling Adaptor Protein / Q000235:genetics / Q000378:metabolism*; D055503:Protein Multimerization / Q000502:physiology*; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D053475:Receptor-Interacting Protein Serine-Threonine Kinase 2 / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*
chemical_list: C119067:NOD1 protein, human; D053474:Nod1 Signaling Adaptor Protein; C506253:RIPK2 protein, human; D053475:Receptor-Interacting Protein Serine-Threonine Kinase 2
keywords: Caspase; Death Domain; Inflammation; Innate Immunity; NF-κB (NF-κB); Nod-like Receptor (NLR); Protein Kinase; Protein-Protein Interaction; Signal Transduction