Cutting Edge: The Toll Pathway Is Required for Resistance to Gram-Positive Bacterial Infections in Drosophila

Abstract

In Drosophila, the response against various microorganisms involves different recognition and signaling pathways, as well as distinct antimicrobial effectors. On the one hand, the immune deficiency pathway regulates the expression of antimicrobial peptides that are active against Gram-negative bacteria. On the other hand, the Toll pathway is involved in the defense against filamentous fungi and controls the expression of antifungal peptide genes. The gene coding for the only known peptide with high activity against Gram-positive bacteria, Defensin, is regulated by both pathways. So far, survival experiments to Gram-positive bacteria have been performed with Micrococcus luteus and have failed to reveal the involvement of one or the other pathway in host defense against such infections. In this study, we report that the Toll pathway, but not that of immune deficiency, is required for resistance to other Gram-positive bacteria and that this response does not involve Defensin.

Inhibitor of Apoptosis (IAP) Proteins-Modulators of Cell Death and Inflammation

“…This provides DIAP2 with an additional docking site, reinforcing complex stability and allowing DIAP2-mediated ubiquitylation of IMD, and quite possibly other components of the signaling complex (Paquette et al 2010). The Ub chains on IMD and DREDD appear to serve as scaffolds for the recruitment of dTAK1, IKK, and the precursor form of the NF-kB transcription factor Relish (Rutschmann et al 2000(Rutschmann et al , 2002Silverman et al 2000Silverman et al , 2003Lu et al 2001;Vidal et al 2001;Kanayama et al 2004;Kleino et al 2005;Zhuang et al 2006;Ferrandon et al 2007). This brings Relish into close proximity of ubiquitylated and active DREDD, allowing DREDDmediated proteolysis of Relish.…”

Correlation of Differential Expression of Silkworm Antimicrobial Peptide Genes with Different Amounts of Rel Family Proteins and Their Gene Transcriptional Activity

“…1,4,5) Gram-positive bacteria and fungi stimulate the Toll pathway, leading to translocation of NF-B transcription factors, while Dorsal and Dorsal immune-factor (Dif) activate target AMP genes such as Drosomycin. [8][9][10] In contrast, the IMD pathway is stimulated by infection with Gramnegative bacteria, and an NF-B factor, Relish, activates expression of AMP genes such as Diptericin. [11][12][13][14] The expression of AMP genes Metchnikowin and Defensin is controlled by both the Toll and the IMD pathway.…”

The Drosophila Toll Pathway Controls but Does Not Clear Candida glabrata Infections

“…w A5001 and DD1 cn bw flies were used as wild-type throughout the experiments because the majority of mutants were generated in these backgrounds. stocks have been described previously (21,22,(31)(32)(33)(34)(35)(36).…”