title: Redox-regulated growth factor survival signaling.
abstract: CONCLUSIONS
  Once the thought of as unwanted byproducts of cellular respiration in eukaryotes, reactive oxygen species (ROS) have been shown to facilitate essential physiological roles. It is now understood that ROS are critical mediators of intracellular signaling. Control of signal transduction downstream of growth factor receptors by ROS is a complex process whose details are only recently coming to light.
  
  
  BACKGROUND
  Indeed, recent evidence points to control of signal propagation by ROS at multiple levels in the typical cascade. Growth factor stimulation activates nicotinamide adenine dinucleotide phosphate (NADPH) oxidases (Noxs) at the membrane, producing superoxide in the extracellular matrix, which is catalyzed to the membrane-permeable hydrogen peroxide (H2O2) that mediates intracellular signaling events.
  
  
  RESULTS
  The potential for H2O2, however, to disrupt cellular functions by damaging proteins and nucleic acids demands that its levels are kept in check by receptor-associated peroxiredoxins. This interplay of Nox and peroxiredoxin activity moderates levels of H2O2 sufficiently to modify signaling partners locally. Among the best studied of these partners are redox-controlled phosphatases that are inactivated by H2O2. Phosphatases regulate signal propagation downstream of receptors, and thus their inactivation allows a further level of control. Transmission of information further downstream to targets such as transcription factors, themselves regulated by ROS, completes this pathway.
  
  
  CONCLUSIONS
  Thus, signal propagation or attenuation can be dictated by ROS at multiple points. Given the complex nature of these processes, we envisage the emerging trends in the field of redox signaling in the context of growth factor stimulation.
authors.affiliation: Tumour Biology Laboratory, Biochemistry Department, Bioscience Research Institute, University College , Cork, Ireland .
authors.forename: John F
authors.initials: JF
authors.lastname: Woolley
authors.forename: Aoife
authors.initials: A
authors.lastname: Corcoran
authors.forename: Gillian
authors.initials: G
authors.lastname: Groeger
authors.forename: William D
authors.initials: WD
authors.lastname: Landry
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Cotter
mesh_terms: D000818:Animals; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism*; D010084:Oxidation-Reduction; D054464:Peroxiredoxins / Q000378:metabolism; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D036341:Intercellular Signaling Peptides and Proteins; D017382:Reactive Oxygen Species; D014157:Transcription Factors; D054464:Peroxiredoxins; D010744:Phosphoric Monoester Hydrolases