STAT4

· signal transducer activity · calcium ion binding· nucleolus· protein phosphorylation · JAK-STAT cascade · cell proliferation · cytokine-mediated signaling pathwaySTAT4是转录因子中信号转导及转录激活蛋白（STAT蛋白）家族的一员。 It is required for the development of Th1 cells from naive CD4+ T cells and IFN-γ production in response to IL-12.人类和鼠类的STAT4基因都位于STAT1基因的附近，这一点暗示了这两个基因由基因重复而来，STAT蛋白都有几个特定的结构域，包括N-端互作结构域，中间的DNA结合结构域（英语：DNA-binding domain），一个SH2结构域以及C-端的转录激活结构域。Distribution of STAT4 is restricted to myeloid cells, thymus and testis. In resting human T cells it is expressed at very low levels, but its production is amplified by PHA stimulation.Two chains of IL-12 receptor form heterodimer after IL-12 binding and activate the receptor associated JAK kinases, termed JAK2 and TYK2. Stat4 is phosphorylated by these tyrosine kinases, homodimerizes via its SH2 domain and translocates into nucleus to activate gene transcription.STAT4 binds to hundreds of sites in the genome, among others to the promoters of genes for cytokines (IFN-γ, TNF), receptors (IL18R1, IL12rβ2, IL18RAP), and signaling factors (MYD88).