| Reporter assay , GST pull down , co immunoprecipitation , and yeast two hybrid assays identified a specific interaction between the N terminal LXXLL motif of Prox 1 and the activation function 2 domain of HNF4alpha . ^^^ Prox 1 strongly inhibited HNF4alpha and peroxisome proliferators activated receptor gamma coactivator 1alpha co activation of the CYP7A1 and PEPCK genes . ^^^ These results suggest that Prox 1 is a novel co regulator of HNF4alpha that may play a key role in the regulation of bile acid synthesis and gluconeogenesis in the liver . . ^^^ |