Mouse IFN-alpha / beta R1 Alexa Fluor® 594-conjugated Antibody

IFN-alpha / beta R1, also known as IFNAR1, belongs to the class II cytokine receptor family of proteins. Class II cytokine receptors form heterodimeric receptor complexes that mediate class II cytokine signals. Subunits of the different receptor complexes are shared and serve multiple functions (1-3). IFN-alpha / beta R1, in association with IFN-alpha / beta R2, is required for propagating antiviral signal transduction triggered by IFN-alpha and IFN-beta (4, 5). The mouse IFN-alpha / beta R1 cDNA encodes a 590 amino acid (aa) precursor including a 26 aa signal sequence, a 403 aa extracellular domain (ECD), a 20 aa transmembrane segment, and a 141 aa cytoplasmic domain (6). The ECD contains three tandem fibronectin type III repeats and is extensively glycosylated. The ECD of mouse IFN-alpha / beta R1 shares 47-48% aa identity with that of human, bovine, porcine, and ovine IFN-alpha / beta R1. IFN-alpha / beta R1 interacts very weakly or not at all with type 1 interferons and does not stably interact with IFN-alpha / beta R2. Ligands associate with IFN-alpha / beta R2, and this complex subsequently forms a stable ternary assembly with IFN-alpha / beta R1 (7, 8). IFN-alpha / beta R1 also associates with IFN-gamma R2 even in the absence of IFN-gamma stimulation (5). Tyrosine phosphorylation within the juxtamembrane cytoplasmic domain of IFN-alpha / beta R1 provides a docking site for the SH2 domains of Tyk2 and STAT2 (9-11). Tyk2 can directly phosphorylate IFN-alpha / beta R1 (10). Tyk2 also increases the level of cell surface expression of IFN-alpha / beta R1 by preventing constitutive internalization (12). Human IFN-alpha / beta R1 contains a nuclear localization signal in its ECD which is required for receptor translocation to the nucleus following interaction with ligand (13).