Interacting pathways of interferon signaling

Interferons (IFNs) are important modifiers of biologic response in vertebrate cells. After IFNs are induced, in response to viral or microbial infections, the IFNs bind to specific receptors on the surface of target cells and cause rapid activation of IFN-stimulated genes. These genes mediate the different biologic effects of the IFNs. The molecular characterization of IFN-induced gene activation led to the discovery of the Jak-Stat signal transduction pathway, which is now known to be shared by many other cytokines, growth factors, and hormones. Protein phosphorylation plays a key role in the Jak-Stat pathway, which consists of a cascade of specific protein-protein interactions that culminate in protein-DNA engagement and specific transcription. Although responses in the signaling pathways to various IFN-alpha species have not been examined in detail, it is likely that subtle differences in receptor interaction between the various IFN-alpha species, whether derived from natural or synthetic genes, may produce an unexpected array of biologic effects and clinical responses.