IndraLab

"The IFN-mediated activation of the Jak-STAT pathway is tightly regulated by various cellular factors such as SOCS family members, USP18, the protein phosphatase 2A (PP2A), and protein inhibitors of STAT (PIAS).[ xref ] Along those lines, SOCS1 and SOCS3 transcriptional expression in hepatocytes remains detectable for only a short period of time upon alfa treatment indicating that by inhibiting Janus kinases both proteins are likely responsible for early termination of STAT activation.[ xref ] In addition, the sustained up-regulation of USP18 was associated with a long-lasting refractory state to IFN-α stimulation in hepatocytes and other primary human cells.[ xref ] The specific interaction of USP18 with IFNAR2 selectively affects IFN—induced signaling while having a marginal effect on other classes of IFNs, including type III IFNs."

"USP18 decreased IFNα binding to U6A cells only in the presence of full length STAT2 but not STAT2ΔCC/DB ( xref ), supporting the notion that interaction of STAT2 and USP18 is important for the type I IFN ligand-receptor binding."