Send to

Choose Destination
EMBO J. 2012 Feb 15;31(4):932-44. doi: 10.1038/emboj.2011.440. Epub 2011 Dec 13.

Phagosomal proteolysis in dendritic cells is modulated by NADPH oxidase in a pH-independent manner.

Author information

Department of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada.


The level of proteolysis within phagosomes of dendritic cells (DCs) is thought to be tightly regulated, as it directly impacts the cell's efficiency to process antigen. Activity of the antimicrobial effector NADPH oxidase (NOX2) has been shown to reduce levels of proteolysis within phagosomes of both macrophages and DCs. However, the proposed mechanisms underlying these observations in these two myeloid cell lineages are dissimilar. Using real-time analysis of lumenal microenvironmental parameters within phagosomes in live bone marrow-derived DCs, we show that the levels of phagosomal proteolysis are diminished in the presence of NOX2 activity, but in contrast to previous reports, the acidification of the phagosome is largely unaffected. As found in macrophages, we show that NOX2 controls phagosomal proteolysis in DCs through redox modulation of local cysteine cathepsins. Aspartic cathepsins were unaffected by redox conditions, indicating that NOX2 skews the relative protease activities in these antigen processing compartments. The ability of DC phagosomes to reduce disulphides was also compromised by NOX2 activity, implicating this oxidase in the control of an additional antigen processing chemistry of DCs.

[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Wiley Icon for PubMed Central
Loading ...
Support Center