The protein encoded by this gene is a member of the STAT family of transcription factors. In response to cytokines and growth factors, STAT family members are phosphorylated by receptor-associated kinases and subsequently form homo- or heterodimers that translocate to the nucleus, where they function as transcriptional activators. This protein plays a central role in mediating IL-4-induced biological responses. It has been shown to induce the expression of BCL2L1/BCL-X(L), which is responsible for the anti-apoptotic activity of IL-4. Knockout studies in mice have demonstrated that this gene is involved in the differentiation of T helper 2 (Th2) cells, the expression of cell surface markers, and immunoglobulin class switching. Alternative splicing generates multiple transcript variants. Upon activation by Janus kinases, Stat6 translocates to the nucleus to regulate cytokine-induced gene expression. Stat6 is activated via phosphorylation at Tyr641 and is essential for cellular responses to IL-4 and IL-13. Additionally, Stat6 is activated by IFN-α in B cells and forms a transcriptionally active complex with Stat2 and p48. Protein phosphatase 2A is also involved in regulating IL-4-mediated Stat6 signaling.
