Nucleocytoplasmic trafficking and stability of the mineralocorticoid receptor

Abstract

The mineralocorticoid receptor (MR) is a ligand inducible sequence specific transcription factor belonging to the nuclear receptor superfamily. In this study, I report the presence of a second NLS (NL2) in MR that mediates a slower translocation of MR to the nucleus in an agonist-dependent manner. I also report that the LBD of MR, containing the NL2, could contain a sequence that prolongs nuclear subcellular localization of the receptor or alternatively lacks an export signal. I report that MR is degraded by the proteasome, that addition of steroid induces further degradation and that the N-terminal portion of MR is responsible for the appearance of higher molecular weight forms of the receptor after aldosterone treatment. Finally, we identified, by using the PESTfind software, a PEST signal starting at position 686 to 711, but confirm that the lysine residue at position 712 is not an acceptor ubiquitin site. (Abstract shortened by UMI.)