Hydrogen peroxide generated extracellularly by receptor–ligand interaction facilitates cell signaling

Abstract Reactive oxygen species (ROS) are key components of postreceptor intracellular signaling pathways; however, the role of ROS in signal initiation is uncertain. We discovered that receptor–ligand interaction caused the generation of hydrogen peroxide (H2O2). Using members of the hematopoietin receptor superfamily, as well as EGF receptor, we show that H2O2 is generated by specific receptor–ligand interaction in cells and in cell-free systems. With cognate ligand, the extracellular domain of the receptor was sufficient for H2O2 generation. We also found that production of H2O2 was diminished in a granulocyte–macrophage colony-stimulating factor receptor mutant unable to bind ligand. Exogenously added H2O2 induced signaling in the absence of ligand, whereas catalase and a membrane-bound peroxiredoxin inhibited ligand-dependent signaling. Our results suggest that H2O2 produced by receptor–ligand interaction is involved as a chemical mediator that facilitates cell signaling. reactive oxygen species kinase cytokine hematopoietin