Major activator of the imd/Relish pathway and is likely to encode a pattern recognition molecule for the humoral immune response (PubMed:11872802, PubMed:22022271). Required for Relish processing and nuclear translocation following proteolytic cleavage (PubMed:11872802). Involved in the response to lipopolysaccharide (LPS) and peptidoglycan of Gram-negative bacteria (PubMed:11872802). The different isoforms probably display different recognition capabilities to various microbial patterns (PubMed:12777387, PubMed:16006509). Mediates the response to LPS and Gram-negative bacteria. Mediates the response to LPS, peptidoglycan and Gram-negative bacteria. Expressed in the fat body and hemocytes. Expressed during larval and pupal stages. Larvae infected with Gram-negative bacteria fail to induce tracheal expression of the antimicrobial peptide gene Drs. Belongs to the N-acetylmuramoyl-L-alanine amidase 2 family.