Transcriptional regulation of importin-α1 by JunD modulates subcellular localization of RNA-binding protein HuR in intestinal epithelial cells.

The RNA-binding protein HuR is crucial for normal intestinal mucosal regeneration by modulating the stability and translation of target mRNAs, but the exact mechanism underlying HuR trafficking between the cytoplasm and nucleus remains largely unknown. Here we report a novel function of transcription factor JunD in the regulation of HuR subcellular localization through the control of importin-α expression in intestinal epithelial cells (IECs). Ectopically expressed JunD specifically inhibited importin-α at the transcription level, and this repression is mediated via interaction with CREB-binding site that was located at the proximal region of importin-α promoter.