title: Iap2 is required for a sustained response in the Drosophila Imd pathway.
abstract: Fruit flies have effective immune response against Gram-negative bacteria. Upon infection, early JNK-signaling pathway mediated response is followed by the action of the Immune deficiency (Imd) signaling cascade, a Drosophila equivalent of mammalian TNF-receptor pathway, leading to the release of antimicrobial peptides. Recently, Tak1-binding protein 2 (Tab2) and Inhibitor of apoptosis 2 (Iap2) were identified as components of the Imd pathway. In this study, we carried out a genome-wide kinetic analysis of the role of Tab2 and Iap2 for immune response in Drosophila S2 cells using oligonucleotide microarrays. Tab2 RNAi abolished the induction of all immune response genes in S2 cells indicating its requirement for signaling both via the Imd and the JNK pathway. The role of Iap2 was more specific. Kinetic analysis indicated that Iap2 is required to sustain antimicrobial peptide gene expression in S2 cells. Furthermore, inactivation of Iap2 by RNAi resulted in impaired microbial resistance in Drosophila in vivo.
authors.affiliation: Institute of Medical Technology, 33014 University of Tampere, and Department of Pediatrics, Tampere University Hospital, Finland.
authors.forename: Susanna
authors.initials: S
authors.lastname: Valanne
authors.forename: Anni
authors.initials: A
authors.lastname: Kleino
authors.forename: Henna
authors.initials: H
authors.lastname: Myllymäki
authors.forename: Jussi
authors.initials: J
authors.lastname: Vuoristo
authors.forename: Mika
authors.initials: M
authors.lastname: Rämet
mesh_terms: D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000096:biosynthesis / Q000235:genetics; D002460:Cell Line; D029721:Drosophila Proteins / Q000235:genetics / Q000502:physiology*; D004331:Drosophila melanogaster / Q000235:genetics / Q000276:immunology*; D007113:Immunity, Innate / Q000235:genetics; D051034:Inhibitor of Apoptosis Proteins / Q000235:genetics / Q000502:physiology*; D008826:Microbial Sensitivity Tests; D015398:Signal Transduction / Q000235:genetics / Q000276:immunology*
chemical_list: D023181:Antimicrobial Cationic Peptides; C111892:DIAP2 protein, Drosophila; D029721:Drosophila Proteins; D051034:Inhibitor of Apoptosis Proteins; C439909:imd protein, Drosophila