Signal transducer and activator of transcription 6 (STAT6) is a transcription factor that is activated by interleukin-4 (IL-4)-induced tyrosine phosphorylation and mediates most of the IL-4-induced gene expression. STAT6 plays a central role in exerting interleukin-4 (IL-4) mediated biological responses and is found to induce the expression of BCL2L1/BCL-XL, which is responsible for the anti-apoptotic activity of IL4. Transcriptional activation by STAT6 requires the interaction with coactivators like p300 and the CREB-binding protein (CBP). NF-?B and tyrosine-phosphorylated Stat6 can directly bind each other in vitro and in vivo, which suggest that the direct interaction between Stat6 and NF-?B may provide a basis for synergistic activation of transcription by IL-4 and activators of NF-?B.