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TNFα potentiates protein‐tyrosine nitration through activation of eNOS and NADPH oxidase localized in caveolae of bovine aortic endothelial cells
Author(s) -
Yang Baohua,
Rizzo Victor
Publication year - 2006
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.20.4.a726-b
Subject(s) - caveolae , lipid raft , nadph oxidase , microbiology and biotechnology , enos , chemistry , peroxynitrite , biochemistry , reactive oxygen species , superoxide , biology , signal transduction , nitric oxide synthase , enzyme
A major source of ROS in endothelial cells is the NADPH oxidase enzyme complex. The selective distributions of any enzyme within the cell have important implications in regulating enzyme effectiveness through facilitating access to local substrates and/or product targets. Since lipid rafts and caveolae provide a spatially preferable environment for a variety of enzyme systems, we sought to determine if NADPH oxidase is present and functional in this plasma membrane compartment in endothelial cells. We found that NADPH oxidase subunits were preassembled and the enzyme functional in membrane rafts/caveolae. In addition, TNFα induced: a) recruitment of p47phox regulatory subunit, b) interaction with the p22phox subunit and c) enhanced ROS production within rafts/caveolae domains. TNFα also induced phosphorylation and activation of eNOS present in plasma membrane raft/caveolae compartments. The dual activation of superoxide and nitric oxide generating systems within the same membrane compartment provided a spatially favorable environment for formation of peroxynitrite as evidence by detection of nitration of tyrosine containing proteins localized to rafts/caveolae. Perturbation of lipid raft/caveolae structural integrity with cholesterol sequestering compounds caused the relocalization of eNOS and NADPH oxidase subunits from the lipid rafts and inhibited TNF.α‐induced peroxynitrite formation. Together, these data provide the first evidence that lipid rafts/caveolae play a role in regulating NADPH oxidase and subsequent ROS generation in endothelial cells. This work was supported by NIH HL66301.