Dual Activation of the Drosophila Toll Pathway by Two Pattern Recognition Receptors

Vanessa Gobert, Marie Gottar, Alexey A. Matskevich, Sophie Rutschmann, Julien Royet, Marcia Belvin, Jules A. Hoffmann, Dominique Ferrandon

Unite Propre de Recherche 9022 du CNRS, Institut de Biologie Moleculaire et Cellulaire, 15 rue Rene Descartes, F67084 Strasbourg Cedex, France.
Exelixis Inc., South San Francisco, CA 94083, USA.

The Toll-dependent defense against Gram-positive bacterial infections in Drosophila is mediated through the peptidoglycan recognition protein SA (PGRP-SA). A mutation termed osiris disrupts the Gram-negative binding protein 1 (GNBP1) gene and leads to compromised survival of mutant flies after Gram-positive infections, but not after fungal or Gram-negative bacterial challenge. Our results demonstrate that GNBP1 and PGRP-SA can jointly activate the Toll pathway. The potential for a combination of distinct proteins to mediate detection of infectious nonself in the fly will refine the concept of pattern recognition in insects.