Fibroblast growth factor receptor 4 (FGFR4) mediates signaling to the prolactin but not the FGFR4 promoter

Yu et al examined whether FGF-19 might regulate its own receptor through the Ets-Ik element in the fibroblast growth factor receptor 4 (FGFR4) promoter. Ets stimulated and dn-Ets inhibited basal FGFR4 and PRL promoter activity. In contrast, Ets enhanced FGF-19-induced PRL activation but failed to confer an effect for FGF-19 on the FGFR4 promoter. They conclude that FGFR4 mediates FGF-19 signaling to the PRL promoter. Their data also suggest a possible functional role for Ik in sorting Ets signals to the FGFR4 promoter, as distinct from the PRL promoter, where Ets partners with Pit1.