Involved in the immune response to bacterial infection. Up-regulated following injection with the Gram-negative bacterium E.coli. Up-regulation increases between 1 and 6 hours after the injection, then expression remains at a relatively steady level until 72 hours when it is strongly up-regulated. Conjugated to URM1, a ubiquitin-like protein. RNAi-mediated knockdown in the fat body or hemocyte of flies infected with the Gram-negative bacterium E.coli results in an increase in bacterial load 24 hours after infection. Belongs to the GILT family. Lacks the conserved active site CXXC motif that is essential for thiol reductase activity. Its enzyme activity is therefore unsure.