Authors: Yoon-Suk Alexander Chung and Christine Kocks

Yoon-Suk Alexander Chung

Department of Pediatrics; Massachusetts General Hospital; Harvard Medical School; Boston, MA USA; Department of Molecular Biology; Massachusetts General Hospital; Harvard Medical School; Boston, MA USA

Christine Kocks

Corresponding author: kocks@molbio.mgh.harvard.edu
Department of Pediatrics; Massachusetts General Hospital; Harvard Medical School; Boston, MA USA; Department of Molecular Biology; Massachusetts General Hospital; Harvard Medical School; Boston, MA USA

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Abstract:

Phagocytosis is an evolutionarily ancient, receptor-driven process, by which phagocytic cells recognize invading microbes and destroy them after internalization. The phagocytosis receptor Eater is expressed exclusively on Drosophila phagocytes and is required for the survival of bacterial infections. In a recent study, we explored how Eater can defend fruit flies against different kinds of bacteria. We discovered that Eater bound to certain types of bacteria directly, while for others bacterial binding was dependent on prior disruption of the bacterial envelope. Similar to phagocytes, antimicrobial peptides and lysozymes are ancient components of animal immune systems. Our results suggest that cationic antimicrobial peptides, as well as lysozymes, can facilitate Eater binding to live Gram-negative bacteria. Both types of molecules promote surface-exposure of bacterial ligands that otherwise would remain buried and hidden under an outer membrane. We propose that unmasking ligands for phagocytic receptors may be a conserved mechanism operating in many animals, including humans. Thus, studying a Drosophila phagocytosis receptor may advance our understanding of innate immunity in general.

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YS Chung, C Kocks. Recognition of pathogenic microbes by the Drosophila phagocytic pattern recognition receptor Eater. J Biol Chem 2011; 286: 26524-32
PMID: 21613218 DOI: 10.1074/jbc.M110.214007