Article
- The EMBO Journal (2002) 21, 6330 - 6337
- doi:10.1093/emboj/cdf661
Subject Categories:
A serpin mutant links Toll activation to melanization in the host defence of Drosophila
Petros Ligoxygakis1,4, Nadège Pelte1,4, Chuanyi Ji2, Vincent Leclerc1, Bernard Duvic1, Marcia Belvin3, Haobo Jiang2, Jules A. Hoffmann1 and Jean-Marc Reichhart1
- Institut de Biologie Moléculaire and Cellulaire, UPR 9022 du CNRS, 15, rue René Descartes, F-67084 Strasbourg Cedex, France
- Department of Entomology and Plant Pathology, Division of Agricultural Sciences and Natural Resources, Oklahoma State University, 127 Noble Research Center, Stillwater, OK 74078, USA
- Exelixis Inc., South San Francisco, CA 94083, USA
- P.Ligoxygakis and N.Pelte contributed equally to this work
Correspondence to:
Jean-Marc Reichhart, E-mail: JM.Reichhart@ibmc.u-strasbg.fr
Received 26 July 2002; Accepted 18 October 2002; Revised 16 October 2002
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.
Keywords:
- Drosophila,
- innate immunity,
- melanization,
- serine protease cascade,
- serpin
