title: A serpin mutant links Toll activation to melanization in the host defence of Drosophila.
abstract: A prominent response during the Drosophila host defence is the induction of proteolytic cascades, some of which lead to localized melanization of pathogen surfaces, while others activate one of the major players in the systemic antimicrobial response, the Toll pathway. Despite the fact that gain-of-function mutations in the Toll receptor gene result in melanization, a clear link between Toll activation and the melanization reaction has not been firmly established. Here, we present evidence for the coordination of hemolymph-borne melanization with activation of the Toll pathway in the Drosophila host defence. The melanization reaction requires Toll pathway activation and depends on the removal of the Drosophila serine protease inhibitor Serpin27A. Flies deficient for this serpin exhibit spontaneous melanization in larvae and adults. Microbial challenge induces its removal from the hemolymph through Toll-dependent transcription of an acute phase immune reaction component.
authors.affiliation: Institut de Biologie Moléculaire and Cellulaire, UPR 9022 du CNRS, 15, rue René Descartes, F-67084 Strasbourg Cedex, France.
authors.forename: Petros
authors.initials: P
authors.lastname: Ligoxygakis
authors.forename: Nadège
authors.initials: N
authors.lastname: Pelte
authors.forename: Chuanyi
authors.initials: C
authors.lastname: Ji
authors.forename: Vincent
authors.initials: V
authors.lastname: Leclerc
authors.forename: Bernard
authors.initials: B
authors.lastname: Duvic
authors.forename: Marcia
authors.initials: M
authors.lastname: Belvin
authors.forename: Haobo
authors.initials: H
authors.lastname: Jiang
authors.forename: Jules A
authors.initials: JA
authors.lastname: Hoffmann
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Reichhart
mesh_terms: D000818:Animals; D004330:Drosophila / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D029721:Drosophila Proteins / Q000097:blood / Q000235:genetics* / Q000378:metabolism*; D006458:Hemolymph / Q000378:metabolism; D007239:Infections / Q000276:immunology; D008543:Melanins / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000378:metabolism*; D015843:Serpins / Q000097:blood / Q000235:genetics* / Q000378:metabolism; D051193:Toll-Like Receptors
chemical_list: D029721:Drosophila Proteins; D008543:Melanins; D011956:Receptors, Cell Surface; D015843:Serpins; C468118:Spn27A protein, Drosophila; C068721:Tl protein, Drosophila; D051193:Toll-Like Receptors