title: RNAi screening identifies mediators of NOD2 signaling: implications for spatial specificity of MDP recognition.
abstract: The intracellular nucleotide-binding oligomerization domain-2 (NOD2) receptor detects bacteria-derived muramyl dipeptide (MDP) and activates the transcription factor NF-κB. Here we describe the regulatome of NOD2 signaling using a systematic RNAi screen. Using three consecutive screens, we identified a set of 20 positive NF-κB regulators including the known pathway members RIPK2, RELA, and BIRC4 (XIAP) as well as FRMPD2 (FERM and PDZ domain-containing 2). FRMPD2 interacts with NOD2 via leucine-rich repeats and forms a complex with the membrane-associated protein ERBB2IP. We demonstrate that FRMPD2 spatially assembles the NOD2-signaling complex, hereby restricting NOD2-mediated immune responses to the basolateral compartment of polarized intestinal epithelial cells. We show that genetic truncation of the NOD2 leucine-rich repeat domain, which is associated with Crohn disease, impairs the interaction with FRMPD2, and that intestinal inflammation leads to down-regulation of FRMPD2. These results suggest a structural mechanism for how polarity of epithelial cells acts on intestinal NOD-like receptor signaling to mediate spatial specificity of bacterial recognition and control of immune responses.
authors.affiliation: Institute of Clinical Molecular Biology,  Christian Albrechts University, D-24105 Kiel,  Germany.
authors.forename: Simone
authors.initials: S
authors.lastname: Lipinski
authors.forename: Nils
authors.initials: N
authors.lastname: Grabe
authors.forename: Gunnar
authors.initials: G
authors.lastname: Jacobs
authors.forename: Susanne
authors.initials: S
authors.lastname: Billmann-Born
authors.forename: Andreas
authors.initials: A
authors.lastname: Till
authors.forename: Robert
authors.initials: R
authors.lastname: Häsler
authors.forename: Konrad
authors.initials: K
authors.lastname: Aden
authors.forename: Maren
authors.initials: M
authors.lastname: Paulsen
authors.forename: Alexander
authors.initials: A
authors.lastname: Arlt
authors.forename: Lars
authors.initials: L
authors.lastname: Kraemer
authors.forename: Nina
authors.initials: N
authors.lastname: Hagemann
authors.forename: Kai Sven
authors.initials: KS
authors.lastname: Erdmann
authors.forename: Stefan
authors.initials: S
authors.lastname: Schreiber
authors.forename: Philip
authors.initials: P
authors.lastname: Rosenstiel
mesh_terms: D000119:Acetylmuramyl-Alanyl-Isoglutamine / Q000378:metabolism* / Q000494:pharmacology; D018938:Caco-2 Cells; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D003424:Crohn Disease / Q000378:metabolism / Q000473:pathology; D020895:Enterocytes / Q000187:drug effects / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D008954:Models, Biological; D050505:Mutant Proteins / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D053473:Nod2 Signaling Adaptor Protein / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding / Q000187:drug effects; D017434:Protein Structure, Tertiary; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D053475:Receptor-Interacting Protein Serine-Threonine Kinase 2 / Q000378:metabolism; D015203:Reproducibility of Results; D015398:Signal Transduction / Q000187:drug effects; D013379:Substrate Specificity / Q000187:drug effects; D062725:Tight Junction Proteins / Q000737:chemistry
chemical_list: C545238:FRMPD2 protein, human; D050505:Mutant Proteins; D016328:NF-kappa B; D053473:Nod2 Signaling Adaptor Protein; D034741:RNA, Small Interfering; D062725:Tight Junction Proteins; D000119:Acetylmuramyl-Alanyl-Isoglutamine; D053475:Receptor-Interacting Protein Serine-Threonine Kinase 2