Interactions of Thyroid Hormone Receptor with Ku Proteins and Interleukin Enhancer Binding Factor 3 Modulate the Promoter Activity of Thyroid-Stimulating Hormone Alpha

抄録

We previously identified Ku proteins and interleukin enhancer binding factor 3 (ILF3) as cofactors for the nuclear receptor farnesoid X receptor and liver receptor homolog-1, respectively. Here we provide further evidence that these cofactors modulate the promoter activity of the nuclear receptor thyroid hormone receptor (TR) target gene, thyroid-stimulating hormone alpha (TSHα), which is negatively regulated by the TR ligand triiodothyronine (T₃). Ku proteins suppressed TSHα promoter activity independent of T₃, whereas ILF3 enhanced TSHα activity, especially in the presence of T₃. Taken together, our results suggest that Ku proteins and ILF3 function as co-regulators for TR-mediated TSHα expression.