A Role for the Orphan Serine hydrolase CG17192 in the Drosophila immune response

Abstract

Highly conserved during evolution, the Serine Hydrolase (SH) superfamily of enzymes is a diverse group of catalysts that conduct a wide range of metabolic events in eukaryotic cells. A recent characterization of the activation of SHs in Drosophila (Kumar et al. 2021) found that the enzymatic activity of CG17192 is enriched in the female hemolymph and male gut. CG17192 is anticipated to be involved in degrading and absorbing a significant fraction (~ 30%) of adult triglycerides in the animal diet. As part of my MS thesis project, I have initiated the functional characterization of CG17192 using in vitro biochemical assays, activity-based proteomics, and lipidomics. I have validated the activity of the SH in-vitro using ABPP (Activity-based protein pro- filing) assay, utilizing the broad-spectrum chemical probe flurophosphonate tagged with either rhodamine. For in-vitro experiments, I have cloned CG17192 for expression in both bacteria and insect cells. Additionally, I have generated a catalytically dead CG17192S179A mutant. Loss of function studies in the midgut via RNAi indicate that CG17192 may function as an immunosuppressor.