Function
Essential for the imd/NF-kappa-B (Imd) humoral and epithelial immune response to Gram-negative bacteria (PubMed:7568155, PubMed:8808632, PubMed:11266367, PubMed:12433364). Functions as an adapter protein that transduces immunity signals from the activation of pathogen recognition receptors (PRRs) by bacterial infection to the Imd signaling pathway (PubMed:7568155, PubMed:11269502, PubMed:11703941, PubMed:12433364, PubMed:20122400). Binding of diaminopimelic acid-type (DAP-type) bacterial peptidoglycans (PGN) causes multimerization or clustering of PGRP receptors which activate the Imd cascade probably by recruiting imd, Fadd and Dredd to the receptor complex (PubMed:11269502, PubMed:12433364, PubMed:20122400). Once in proximity, Dredd cleaves imd in a Fadd-dependent manner to enable its association and activation by the ubiquitin E3-ligase DIAP2 (PubMed:20122400). The activated form of imd recruits and activates the Tab2/Tak1 complex thus acting upstream of the IKK complex (ird5 and key) to activate Rel and induce the expression of antimicrobial peptides such as Def, Dpt and Cecropin (PubMed:7568155, PubMed:8808632, PubMed:11703941, PubMed:12433364, PubMed:19837371, PubMed:20122400, PubMed:11266367). Also able to inhibit the viral replication of the Sindbis virus (PubMed:19763182). Involved in promoting the polyubiquitination and stability of faf which in turn, regulates the Imd pathway by controlling imd polyubiquitination and/or stability; they may therefore form a regulatory feedback mechanism within the Imd pathway (PubMed:23919485). Not required for the cuticle melanization immune response to bacterial challenge (PubMed:11266367).