Recombinant Human IFN-gamma R2 His-tag Protein, CF

IFN‑ gamma  R2 (Interferon gamma receptor 2; also called IFN‑ gamma R beta IFN‑ gamma  RII, or AF1) is a 60‑64 kDa type I transmembrane glycoprotein that is a member of the class II cytokine receptor family of molecules (1). It is widely expressed as part of a preassembled cell surface multimeric complex. In the absence of IFN‑ gamma, the complex contains two each of IFN‑ gamma  R1, R2 and Jak1 molecules (2). Binding of IFN‑ gamma to IFN‑ gamma  R1 recruits Jak2 to IFN‑ gamma  R2 and initiates phosphorylation, STAT1 binding, conformational changes, and transcriptional regulation, which mainly inhibits proliferation and/or promotes apoptosis (2, 3).  Within the ECD, human IFN‑ gamma  R2 shares 56% aa sequence identity with mouse IFN‑ gamma  R2.  IFN‑ gamma  R1 and R2 must be from the same species for receptor complexes to be active, and human IFN‑ gamma is not active on the mouse IFN‑ gamma receptor complex (1, 2). IFN‑ gamma  R1 is essential for ligand binding and is more constitutively expressed, while IFN‑ gamma  R2 is essential for signaling, and its more limited expression controls cell response to IFN‑ gamma (2, 3). For example, mouse T cell IFN‑ gamma  R2 is down‑regulated during differentiation to subtypes such as Th1 which produce IFN‑ gamma. (3, 4) This allows expansion of activated cells without growth arrest due to paracrine response to IFN‑ gamma. Following expansion, IFN‑ gamma  R2 is re‑expressed to limit the immune reaction (5). IFN‑ gamma  signaling mediates control of intracellular pathogens such as mycobacteria (3, 4, 6). In humans, deficiency of IFN‑ gamma  R2 or other IFN‑ gamma pathway molecules causes the MSMD (mendelian susceptibility to mycobacterial diseases) syndrome (6‑8).