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NADPH oxidase flavocytochrome b localizes to Rab11‐positive recycling endosomes in macrophages
Author(s) -
Casbon Amy Jo,
Dunn Kenneth W.,
Allen LeeAnn,
Dinauer Mary C.
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.2_supplement.552
Subject(s) - endosome , nadph oxidase , p22phox , microbiology and biotechnology , endoplasmic reticulum , chinese hamster ovary cell , subcellular localization , protein subunit , endocytic cycle , chemistry , intracellular , biology , biochemistry , reactive oxygen species , cell , endocytosis , cytoplasm , gene , receptor
Altering the localization of flavocytochrome b , the redox center of the phagocyte NADPH oxidase, has been suggested to be a mechanism by which pathogens evade oxidative killing in macrophages. Flavocytochrome b is a membrane heterodimer consisting of a large subunit gp91 phox (NOX2) and a smaller subunit, p22 phox . While flavocytochrome b is found primarily in specific granules in neutrophils, the localization of flavocytochrome b in macrophages has not been well characterized. The goal of these studies was to determine the subcellular localization of flavocytochrome b in CHO‐K1 (Chinese Hamster Ovary), RAW 264.7 (murine macrophage), and primary murine bone marrow derived macrophages utilizing live imaging of fluorescent‐tagged gp91 phox and p22 phox subunits and immunofluorescent staining. Results were similar in all three cell types. We found that unassembled subunits localize to the endoplasmic reticulum, while the flavocytochrome b heterodimer efficiently localizes not only to the plasma membrane, but also to Rab11‐positive recycling endosomes. These studies show for the first time that flavocytochrome b localizes to an intracellular compartment in macrophages that recycles to the plasma membrane. Future studies will address whether flavocytochrome b localization to recycling endosomes is disrupted by pathogens known to evade oxidative killing. This work was supported in part by National Institutes of Health Grants RO1 HL45635 (to M.C.D) and T32‐DK007519 (to A.J.C).