Interaction of IL-4 with the IL-4 receptor on the surface of an activated CD4 T cell leads to the activation of STAT6 and production of a small amount of GATA-3. GATA-3 forms a complex with c-Myb and Menin that interacts with the GATA-3 exon 1b promoter and increases expression of GATA-3 in differentiating Th2 cells. In principle, this complex could maintain transcription at the GATA-3 locus without further IL-4 signaling. After further maturation, MLL joins c-Myb, GATA-3, and Menin on the exon 1b promoter in Th2 effector/memory cells, potentially acting to maintain the transcriptionally active GATA-3 promoter. Professional illustration by A. Y. Chen.