ABSTRACT
Redox signaling pathways enable cells to respond to oxidative stress, and to oxidants such as hydrogen peroxide that are generated in a controlled manner in cells to activate or modulate signal transduction pathways. In the best characterized systems, signal transmission occurs via transient oxidation of specific cysteine residues in regulatory proteins, including kinases, phosphatases, and transcription factors. This chapter provides a general overview of these signaling processes, and identifies unresolved questions regarding the mechanisms and biological significance of redox signaling. Several intermediates can be generated during oxidation, and any changes in cells that impact on catalyst and intermediate levels will alter fluorescence independent of hydrogen peroxide levels. Phagocytic white blood cells are a major source of hydrogen peroxide during inflammation. Various growth factors, hormones, inflammatory mediators, and death receptor ligands are reported to increase NOX activity in cells, with the resultant hydrogen peroxide proposed to regulate many aspects of cell function ranging from proliferation and differentiation to cell death.
