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Updated: Jul 10, 2026
Assessing the Cellular Immune Response of the Fruit Fly, Drosophila melanogaster, Using an In Vivo Phagocytosis Assay
Published on: April 10, 2019
Peptidoglycan recognition protein LF: a negative regulator of Drosophila immunity
Carina Persson1, Sandra Oldenvi, Håkan Steiner
1Department of Genetics, Microbiology, and Toxicology, University of Stockholm, S-106 91 Stockholm, Sweden.
Abstract:
Peptidoglycan recognition proteins (PGRPs) play important roles in the innate immune defence. Each PGRP detects a distinct subset of peptidoglycans and initiate immune signalling or enzymatic degradation of peptidoglycans. Here we characterize one of the 13 Drosophila PGRPs, PGRP-LF. PGRP-LF is membrane bound and has its two PGRP domains, z and w, localized outside the cell. Our data demonstrate that the z-and w-domain differ in their affinities to peptidoglycan. The z-domain has affinity to several groups of peptidoglycans while the w-domain only recognizes peptidoglycan from Escherichia coli. In addition, we observed that overexpression of PGRP-LF in Drosophila melanogaster Schneider 2 cells (S2 cells) promotes aggregation of cells. Furthermore, following immune stimulation of S2 cells overexpressing PGRP-LF, we noticed a reduced up-regulation of expression of antimicrobial peptide genes, in consonance with an immune suppressive role for PGRP-LF.
Insights
Peptidoglycan recognition proteins (PGRPs) like PGRP-LF are crucial for innate immunity. This study reveals PGRP-LF
Area of Science:
- Immunology
- Molecular Biology
- Cell Biology
Background:
- Peptidoglycan recognition proteins (PGRPs) are key components of the innate immune system.
- PGRPs recognize diverse peptidoglycans to initiate immune signaling or degradation.
- Drosophila melanogaster possesses 13 distinct PGRP genes involved in immune defense.
Purpose of the Study:
- To characterize the function and properties of PGRP-LF, a membrane-bound PGRP in Drosophila.
- To investigate the peptidoglycan binding specificities of PGRP-LF's z and w domains.
- To explore the role of PGRP-LF in cellular aggregation and immune gene regulation.
Main Methods:
- Biochemical characterization of PGRP-LF domains.
- Analysis of peptidoglycan binding affinities.
- Overexpression studies in Drosophila melanogaster Schneider 2 (S2) cells.
- Assessment of antimicrobial peptide gene expression following immune stimulation.
Main Results:
- PGRP-LF is a membrane-bound protein with extracellular z and w domains.
- The z-domain exhibits broad peptidoglycan binding, while the w-domain is specific to E. coli peptidoglycan.
- Overexpression of PGRP-LF induces cell aggregation in S2 cells.
- PGRP-LF overexpression leads to reduced antimicrobial peptide gene induction upon immune challenge.
Conclusions:
- PGRP-LF possesses distinct peptidoglycan recognition specificities through its z and w domains.
- PGRP-LF influences cell behavior, promoting aggregation.
- PGRP-LF appears to play an immune-suppressive role in Drosophila innate immunity.
