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Measuring Phagosome pH by Ratiometric Fluorescence Microscopy
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Measuring Phagosome pH by Ratiometric Fluorescence Microscopy

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Rab27a regulates phagosomal pH and NADPH oxidase recruitment to dendritic cell phagosomes

Carolina Jancic1, Ariel Savina, Christina Wasmeier

  • 1Institut Curie, INSERM U653, Immunité et Cancer, 26 rue d'Ulm, 75248 Paris, Cedex 05, France.

Nature Cell Biology
|March 14, 2007
PubMed

Insights

Dendritic cells use Rab27a to recruit inhibitory organelles, limiting phagosome acidification and antigen degradation. This process is crucial for effective antigen cross-presentation to T lymphocytes.

Area of Science:

  • Immunology
  • Cell Biology
  • Molecular Biology

Background:

  • Dendritic cells (DCs) process antigens in phagosomes for T cell recognition.
  • Excessive phagosome degradation can destroy T cell epitopes.
  • NADPH oxidase NOX2 recruitment limits phagosome acidification and degradation.

Purpose of the Study:

  • To investigate the role of Rab27a in regulating phagosome acidification and antigen degradation in DCs.
  • To understand the mechanism by which DCs control proteolytic activity in phagosomes for antigen cross-presentation.

Main Methods:

  • Utilized dendritic cells derived from Rab27a-deficient ashen mice.
  • Analyzed phagosome acidification and antigen degradation levels.
  • Investigated the recruitment dynamics of lysosome-related organelles containing NOX2 subunits to phagosomes.

Main Results:

  • Rab27a-deficient DCs exhibit increased phagosome acidification and antigen degradation.
  • This leads to a defect in antigen cross-presentation.
  • Delayed recruitment of NOX2-containing organelles to phagosomes underlies enhanced acidification.

Conclusions:

  • Rab27a-dependent recruitment of specific lysosome-related organelles to phagosomes is essential for limiting acidification.
  • This mechanism continuously controls phagosome degradation in DCs, thereby promoting antigen cross-presentation.

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