Toll-dependent and Toll-independent immune responses in Drosophila

Toll and Toll-like receptors in Drosophila.

The Drosophila Toll receptor controls the immune response to Gram-positive bacteria and fungi by activating a signalling pathway partially conserved throughout evolution. The Drosophila genome encodes eight additional Toll-related receptors, most of which appear to carry out developmental rather than immune functions. One exception may be Toll-9, which shares structural and functional similarit...

Specific calcineurin isoforms are involved in Drosophila toll immune signaling.

Because excessive or inadequate responses can be detrimental, immune responses to infection require appropriate regulation. Networks of signaling pathways establish versatility of immune responses. Drosophila melanogaster is a powerful model organism for dissecting conserved innate immune responses to infection. For example, the Toll pathway, which promotes activation of NF-κB transcription fac...

Toll receptors: a central element in innate immune responses.

Toll-like receptors are key participants in innate immune responses.

During an infection, one of the principal challenges for the host is to detect the pathogen and activate a rapid defensive response. The Toll-like family of receptors (TLRs), among other pattern recognition receptors (PRR), performs this detection process in vertebrate and invertebrate organisms. These type I transmembrane receptors identify microbial conserved structures or pathogen-associated...

Drosophila Dicer-2 has an RNA interference–independent function that modulates Toll immune signaling

Dicer-2 is the central player for small interfering RNA biogenesis in the Drosophila RNA interference (RNAi) pathway. Intriguingly, we found that Dicer-2 has an unconventional RNAi-independent function that positively modulates Toll immune signaling, which defends against Gram-positive bacteria, fungi, and some viruses, in both cells and adult flies. The loss of Dicer-2 expression makes fruit f...