Breaking the Mold

Science's STKE  09 Jul 2002:
Vol. 2002, Issue 140, pp. tw244-TW244
DOI: 10.1126/stke.2002.140.tw244

Drosophila protect themselves against bacterial and fungal infection by secreting antimicrobial peptides from the fat body, the insect equivalent of the liver. One mechanism required for initiating this in response to Gram-positive bacteria and fungi is provided by the Toll pathway, which is activated via binding of a proteolytically cleaved form of its ligand Späetzle. Using mutagenesis screening, Ligoxygakis et al. identified mutants for a serine protease gene named persephone, which suppressed the Toll-dependent antifungal response. Unlike other activators of the Toll pathway, persephone has no inherent microbial recognition domain, which suggests that it depends on an upstream fungal receptor to initiate its cleavage of Späetzle.

P. Ligoxygakis, N. Pelte, J. A. Hoffmann, J.-M. Reichhart, Activation of Drosophila Toll during fungal infection by a blood serine protease. Science 296, 114-116 (2002). [Abstract] [Full Text]