NADPH oxidase activity controls phagosomal proteolysis in macrophages through modulation of the lumenal redox environment of phagosomes
- 24 May 2010
- journal article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences of the United States of America
- Vol. 107 (23), 10496-10501
- https://doi.org/10.1073/pnas.0914867107
Abstract
The phagosomal lumen in macrophages is the site of numerous interacting chemistries that mediate microbial killing, macromolecular degradation, and antigen processing. Using a non-hypothesis-based screen to explore the interconnectivity of phagosomal functions, we found that NADPH oxidase (NOX2) negatively regulates levels of proteolysis within the maturing phagosome of macrophages. Unlike the NOX2 mechanism of proteolytic control reported in dendritic cells, this phenomenon in macrophages is independent of changes to lumenal pH and is also independent of hydrolase delivery to the phagosome. We found that NOX2 mediates the inhibition of phagosomal proteolysis in macrophages through reversible oxidative inactivation of local cysteine cathepsins. We also show that NOX2 activity significantly compromises the phagosome's ability to reduce disulfides. These findings indicate that NOX2 oxidatively inactivates cysteine cathepsins through sustained ablation of the reductive capacity of the phagosomal lumen. This constitutes a unique mechanism of spatiotemporal control of phagosomal chemistries through the modulation of the local redox environment. In addition, this work further implicates the microbicidal effector NOX2 as a global modulator of phagosomal physiologies, particularly of those pertinent to antigen processing.Keywords
This publication has 37 references indexed in Scilit:
- Monitoring compartment-specific substrate cleavage by cathepsins B, K, L, and S at physiological pH and redox conditionsBMC Biochemistry, 2009
- The macrophage marches on its phagosome: dynamic assays of phagosome functionNature Reviews Immunology, 2009
- The Small GTPase Rac2 Controls Phagosomal Alkalinization and Antigen Crosspresentation Selectively in CD8+ Dendritic CellsImmunity, 2009
- Recording Phagosome Maturation Through the Real-Time, Spectrofluorometric Measurement of Hydrolytic ActivitiesMethods in molecular biology (Clifton, N.J.), 2009
- Intraphagosomal measurement of the magnitude and duration of the oxidative burst.Traffic, 2009
- NADPH oxidase controls phagosomal pH and antigen cross-presentation in human dendritic cellsBlood, 2008
- GILT is a critical host factor for Listeria monocytogenes infectionNature, 2008
- Real-Time Spectrofluorometric Assays for the Lumenal Environment of the Maturing PhagosomeMethods in molecular biology (Clifton, N.J.), 2008
- Phagocytosis and antigen presentation in dendritic cellsImmunological Reviews, 2007
- Enhancing immunogenicity by limiting susceptibility to lysosomal proteolysisThe Journal of Experimental Medicine, 2006