A systems biology analysis of the Drosophila phagosome
LM Stuart 1,5 , J Boulais 3, GM Charriere 1 , EJ Hennessy 1, S Brunet 3, I Jutras 3, G Goyette 3, C Rondeau 3, S Letarte 3, H Huang 2, P Ye 2 , F Morales 4, C Kocks 1, JS Bader 2, M Desjardins 3 and RAB Ezekowitz 1
- 1Laboratory of Developmental Immunology, Massachusetts General Hospital/ Harvard Medical School, 55 Fruit Street, Boston, MA 02114,USA*
- 2 Department of Biomedical Engineering and High-Throughput Biology Center, Johns Hopkins University, 3400 N. Charles St., Baltimore, Maryland 21218, USA*
- 3 Departement de pathologie et biologie cellulaire, Universite de Montreal, Montreal, Quebec H3C 3J7, Canada*
- 4 Department of Biomedical Engineering, Faculty of Medicine, McGill University, Montreal, Quebec, Canada
- 5 MRC Centre for Inflammation Research, The University of Edinburgh, The Queen's Medical Research Institute, 47 Little France Crescent, Edinburgh, EH16 4TJ, UK.
Phagocytes play a critical role in remodelling tissues during embryogenesis and thereafter are central effectors of immune defense 1, 2. During phagocytosis particles are internalised into ‘phagosomes’, organelles from which immune processes such as microbial destruction and antigen-presentation are initiated 3. Importantly, certain pathogens have evolved mechanisms to evade the immune system and persist undetected by within phagocytes and it is evident therefore, that a detailed knowledge of this process is essential to understand many aspects of innate and adaptive immunity. However, despite the important role of phagosomes in immunity, their components and organisation are not fully defined. Here we present a systems biology analysis of phagosomes isolated from cells derived from the genetically tractable model organism Drosophila melanogaster and address the complex dynamic interactions between proteins within this organelle and their involvement in particle engulfment. Proteomic analysis identified 617 proteins potentially associated with Drosophila phagosomes, which were organised by protein-protein interactions to generate the ‘phagosome interactome’, a detailed protein-protein interaction network of this sub-cellular compartment. These networks predicted both the architecture of the phagosome and putative biomodules. The contribution of each protein and complex to bacterial internalisation were tested by RNAi and identified known components of the phagocytic machinery. In addition, the prediction and validation of novel regulators of phagocytosis such as the ‘exocyst’ 4, a macromolecular complex required for exocytosis but not previously implicated in phagocytosis, validates this strategy. In generating this ‘systems-based model’, we demonstrate the power of applying this approach to study complex cellular processes and organelles and anticipate that this detailed model of the phagosome will provide a new framework for studying host-pathogen interactions and innate immunity.
To access to the article on Nature journal website please follow this link: A systems biology analysis of the Drosophila phagosome
The generation of the phagosome interactome
A high resolution picture of the interaction map is available here
Gene Ontology classification of phagosome proteins
See DAG files (interactive trees) on the Biomodules page
Full supplementary data including proteomic list and RNAi screen data are available through Nature on-line publication, and will posted on this website in few months.