The nuclear receptor hepatocyte nuclear factor 4alpha acts as a morphogen to induce the formation of microvilli.

Microvilli are actin-based organelles found on apical plasma membranes that are involved in nutrient uptake and signal transduction. Numerous components, including ezrin/radixin/moesin (ERM) proteins, have been identified that link filamentous actins to transmembrane proteins, but the signals driving microvillus biogenesis are not known. In this study, we show that the conditional and/or ectopic expression of a nuclear receptor, hepatocyte nuclear factor 4alpha (HNF4alpha), triggers microvillus morphogenesis. We also demonstrate that HNF4alpha expression induces ERM-binding phosphoprotein 50 (EBP50) expression and that attenuation of EBP50 using RNA interference inhibits microvillus development. We conclude that HNF4alpha acts as a morphogen to trigger microvillus formation.