Toll-related receptor which binds to the neurotrophin spz5 (PubMed:10973475, PubMed:23892553). Functions in olfactory circuit assembly by promoting synaptic partner matching between olfactory receptor neurons (ORN) axons and projection neurons (PN) dendrites partners in the antennal lobe (PubMed:25741726). Involved in the targeting of specific classes of PN dendrites (Va1d, Va1v, DC3 and DA1) (PubMed:25741726). Functions with Toll-7 to regulate motor axon targeting and neuronal survival in the central nervous system (CNS) (PubMed:23892553). Possibly functions with 18w and Toll-8 during convergent extension, to help direct proper planar cell polarity, cell intercalation and axis elongation (PubMed:25363762). Promotes heterophilic cell adhesion with 18w in vitro (PubMed:25363762). May be an upstream component of the NF-kappa-B (rel) regulatory cascade (PubMed:23892553). Expressed 48 hours after puparium formation in lateral glomeruli in the anterior and central regions of the antennal lobe, including the DA1, VA1d, VA1v, DC3. DC1, DA4l and DA4m glomeruli (at protein level) (PubMed:25741726). Expressed zygotically (PubMed:12617819). High levels of expression in embryos and pupae, and relatively low levels of expression in larvae and adults (PubMed:10973475). At cellular blastoderm stage, expressed as several segmentally separated stripes, with the anterior stripes appearing first (PubMed:12617819). At germ band extension, strongly expressed in the delaminating neuroblasts (PubMed:12617819). Expression decreases at germ band extension, remaining in a specific subset of neurons in the central nervous system (PubMed:12617819). Expressed in 6 segmentally repeated stripes in the germband (PubMed:25363762). In larvae, detected in the fat body (PubMed:12617819). In larvae, expressed in the optic lobes and the ventral nerve cord of the CNS (PubMed:23892553). Expressed 48 hours after puparium formation in ORN axons and PN dendrites that target to largely overlaping glomeruli (PubMed:25741726). Viable (PubMed:25741726). Dorsomedial or dorsolateral mistargeting of VA1d ORN axons (PubMed:25741726). No effect on the immune response to septic injury using a mixture of Gram-positive and Gram-negative bacteria; adult flies are able induce expression of antibacterial peptide genes (Drs, AttA, DptA and Mtk) and mount a proper innate immune response (PubMed:21158756). Belongs to the Toll-like receptor family. In some plant proteins and in human SARM1, the TIR domain has NAD(+) hydrolase (NADase) activity (By similarity). However, despite the presence of the catalytic Asp residue, the isolated TIR domain of human TLR4 lacks NADase activity (By similarity). Based on this, it is unlikely that Toll-like receptors have NADase activity.