IFN-gamma R2

IFN-gamma R2, one of the subunit of IFN-gamma receptor, is a receptor for IFN-gamma. IFN-gamma R2 is the signal-transducing chain of the IFN-gamma receptor. IFN-gamma R2 can associate with IFN-gamma R1 to form a functional receptor. Upon binding with IFN-gamma, IFNγR2 and IFNγR1 oligomerize and transphosphorylate[1]. Then, the downstream signaling components JAK1 and JAK2 are phosphorylated and activated, thereby creating a binding site for STAT1. Phosphorylated STAT1 leads to dimerization and translocates to the nucleus, where it regulates the expression of IFN-responsive genes (e.g. CD54)[2]. Human IFN-gamma R2 consists of extracellular domain (S28-Q247), helical domain (V248-F268), and cytoplasmic domain (L269-L337). IFN-gamma R2 is constitutively expressed at low levels, and the expression is regulated by the state of cellular differentiation or activation. IFN-gamma R2 is highly expressed on myeloid cells, moderately on B cells and low on T cells. The expression of IFN-gamma R2 can dictate the Th1–Th2 phenotype switch and modulate the subsequent immune response[1][2]. IFN-gamma R2 is important for innating immune defense against mycobacterial infections. Defects in IFN-gamma R2 caused mendelian susceptibility to mycobacterial disease (MSMD)[2].