Interferon alpha/beta receptor 1 (IFN alpha / beta R1), also known as IFNAR1, are present in all tissues and even on the surface of most IFN-resistant cells. Isoform 1, isoform 2 and isoform 3 are expressed in the IFN-alpha sensitive myeloma cell line U266B1. Isoform 2 and isoform 3 are expressed in the IFN-alpha resistant myeloma cell line U266R. Isoform 1 is not expressed in IFN-alpha resistant myeloma cell line U266R. It interacts with STAT1 and STAT2, the interaction requires its phosphorylation at Tyr-466. It also interacts with FBXW11, the substrate recognition component of a SCF (SKP1-CUL1-F-box protein) E3 ubiquitin-protein ligase complex.