title: The tandem CARDs of NOD2: intramolecular interactions and recognition of RIP2.
abstract: Caspase recruitment domains (CARDs) are homotypic protein interaction modules that link the stimulus-dependent assembly of large signaling platforms such as inflammasomes to the activation of downstream effectors that often include caspases and kinases and thereby play an important role in the regulation of inflammatory and apoptotic signaling pathways. NOD2 belongs to the NOD-like (NLR) family of intracellular pattern recognition receptors (PRR) and induces activation of the NF-κB pathway in response to the recognition of bacterial components. This process requires the specific recognition of the CARD of the protein kinase RIP2 by the tandem CARDs of NOD2. Here we demonstrate that the tandem CARDs of NOD2 are engaged in an intramolecular interaction that is important for the structural stability of this region. Using a combination of ITC and pull-down experiments we identify distinct surface areas that are involved in the intramolecular tandem CARD interaction and the interaction with the downstream effector RIP2. Our findings indicate that while CARDa of NOD2 might be the primary binding partner of RIP2 the two CARDs of NOD2 do not act independently of one another but may cooperate to from a binding surface that is distinct from that of single CARDs.
authors.affiliation: Division of Molecular Structure, MRC-National Institute for Medical Research, London, United Kingdom.
authors.forename: Veronica
authors.initials: V
authors.lastname: Fridh
authors.forename: Katrin
authors.initials: K
authors.lastname: Rittinger
mesh_terms: D000595:Amino Acid Sequence; D006801:Humans; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D016328:NF-kappa B / Q000378:metabolism; D053473:Nod2 Signaling Adaptor Protein / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D053475:Receptor-Interacting Protein Serine-Threonine Kinase 2 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D013816:Thermodynamics
chemical_list: D016328:NF-kappa B; C429018:NOD2 protein, human; D053473:Nod2 Signaling Adaptor Protein; D011993:Recombinant Fusion Proteins; C506253:RIPK2 protein, human; D053475:Receptor-Interacting Protein Serine-Threonine Kinase 2