Sensing of 'danger signals' and pathogen-associated molecular patterns defines binary signaling pathways 'upstream' of Toll.
In drosophila, molecular determinants from fungi and Gram-positive bacteria are detected by circulating pattern-recognition receptors. Published findings suggest that such pattern-recognition receptors activate as-yet-unidentified serine-protease cascades that culminate in the cleavage of Spätzle, the endogenous Toll receptor ligand, and trigger the immune response. We demonstrate here that the protease Grass defines a common activation cascade for the detection of fungi and Gram-positive bacteria mediated by pattern-recognition receptors. The serine protease Persephone, shown before to be specific for fungal detection in a cascade activated by secreted fungal proteases, was also required for the sensing of proteases elicited by bacteria in the hemolymph. Hence, Persephone defines a parallel proteolytic cascade activated by 'danger signals' such as abnormal proteolytic activities.
El Chamy
Laure
L
Institut de Biologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique Unité Propre de Recherche 9022, Université Louis Pasteur, Strasbourg Cedex, France.
Leclerc
Vincent
V
Caldelari
Isabelle
I
Reichhart
Jean-Marc
JM
D000818:Animals; D030801:Animals, Genetically Modified; D004330:Drosophila / Q000276:immunology* / Q000382:microbiology; D029721:Drosophila Proteins / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D005658:Fungi / Q000276:immunology; D006094:Gram-Positive Bacteria / Q000276:immunology; D016908:Gram-Positive Bacterial Infections / Q000276:immunology; D017403:In Situ Hybridization; D009181:Mycoses / Q000276:immunology; D010447:Peptide Hydrolases / Q000276:immunology / Q000378:metabolism; D051192:Receptors, Pattern Recognition / Q000276:immunology* / Q000378:metabolism; D012697:Serine Endopeptidases / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D015398:Signal Transduction / Q000276:immunology*; D051193:Toll-Like Receptors / Q000276:immunology* / Q000378:metabolism
D029721:Drosophila Proteins; D051192:Receptors, Pattern Recognition; D051193:Toll-Like Receptors; C086179:spz protein, Drosophila; D010447:Peptide Hydrolases; D012697:Serine Endopeptidases; C460880:psh protein, Drosophila