Stat6 Background Information
Membrane receptor signaling by various ligands, including interferons and growth hormones like EGF, induces activation of Jak kinases, which then leads to tyrosine phosphorylation of the various STAT transcription factors (1,2). Activated STAT proteins form dimers, translocate to the nucleus, bind to specific response elements in promoters of target genes, and transcriptionally activate these genes (3). Stimulation of susceptible cells by interleukin-4 (IL-4) leads to activation of Stat6 through the phosphorylation of tyrosine and serine residues (4,5). IL-4 activation of Stat6 also leads to dimerization, which directs Stat6 to the nucleus, and renders it a sequence-specific transcription factor (4,6). Stat6 is also tyrosine-phosphorylated in response to IL-15, and is involved in IL-4 activated signaling pathways (5,7). The activation of Stat6 by JAK family protein tyrosine kinases is essential for the full response of cells to IL-4 (8).
