Related Experiment Video
Updated: Apr 16, 2026
Study of Phagolysosome Biogenesis in Live Macrophages
Published on: March 10, 2014
Quantitative proteome analysis of temporally resolved phagosomes following uptake via key phagocytic receptors
Brian D Dill1, Marek Gierlinski2, Anetta Härtlova1
1From the ‡MRC Protein Phosphorylation and Ubiquitylation Unit.
Abstract:
Macrophages operate at the forefront of innate immunity and their discrimination of foreign versus "self" particles is critical for a number of responses including efficient pathogen killing, antigen presentation, and cytokine induction. In order to efficiently destroy the particles and detect potential threats, macrophages express an array of receptors to sense and phagocytose prey particles. In this study, we accurately quantified a proteomic time-course of isolated phagosomes from murine bone marrow-derived macrophages induced by particles conjugated to seven different ligands representing pathogen-associated molecular patterns, immune opsonins or apoptotic cell markers. We identified a clear functional differentiation over the three timepoints and detected subtle differences between certain ligand-phagosomes, indicating that triggering of receptors through a single ligand type has mild, but distinct, effects on phagosome proteome and function. Moreover, our data shows that uptake of phosphatidylserine-coated beads induces an active repression of NF-κB immune responses upon Toll-like receptor (TLR)-activation by recruitment of anti-inflammatory regulators to the phagosome. This data shows for the first time a systematic time-course analysis of bone marrow-derived macrophages phagosomes and how phagosome fate is regulated by the receptors triggered for phagocytosis.
Insights
Macrophages distinguish foreign from self particles using receptors. This study reveals how different ligands trigger distinct phagosome proteomes and functions, including NF-κB immune response regulation.
Area of Science:
- Immunology
- Cell Biology
- Proteomics
Background:
- Macrophages are key innate immune cells that engulf particles via specific receptors.
- Phagosome maturation and function are crucial for immune responses like pathogen killing and antigen presentation.
- Understanding receptor-ligand interactions is vital for deciphering macrophage-mediated immunity.
Purpose of the Study:
- To perform a proteomic time-course analysis of phagosomes in murine bone marrow-derived macrophages.
- To investigate how different ligands (pathogen-associated molecular patterns, immune opsonins, apoptotic cell markers) affect phagosome composition and function.
- To elucidate the regulatory mechanisms controlling phagosome fate upon receptor triggering.
Main Methods:
- Isolation and proteomic analysis of phagosomes from murine bone marrow-derived macrophages at three distinct time points.
- Stimulation of macrophages with particles conjugated to seven different ligands.
- Quantitative mass spectrometry to identify and quantify phagosomal proteins.
Main Results:
- Distinct functional differentiation of phagosomes was observed over time.
- Subtle but significant proteomic and functional differences were detected between phagosomes triggered by various ligands.
- Uptake of phosphatidylserine-coated beads actively repressed NF-κB immune responses via recruitment of anti-inflammatory regulators to the phagosome upon Toll-like receptor activation.
Conclusions:
- Phagosome proteome and function are dynamically regulated by the specific receptors engaged during phagocytosis.
- Single ligand-receptor interactions can induce specific, albeit mild, effects on phagosome maturation and immune signaling.
- This study provides a systematic temporal analysis of macrophage phagosomes, revealing novel insights into immune regulation.
