Regulation of glucocorticoid receptor activity by 14–3-3-dependent intracellular relocalization of the corepressor RIP140

J Zilliacus, E Holter, H Wakui, H Tazawa… - Molecular …, 2001 - academic.oup.com
J Zilliacus, E Holter, H Wakui, H Tazawa, E Treuter, JA Gustafsson
Molecular Endocrinology, 2001academic.oup.com
Abstract Proteins belonging to the 14–3-3 family interact with various regulatory proteins
involved in cellular signaling, cell cycle regulation, or apoptosis. 14–3-3 proteins have been
suggested to act by regulating the cytoplasmic/nuclear localization of their target proteins or
by acting as molecular scaffolds or chaperones. We have previously shown that
overexpression of 14–3-3 enhances the transcriptional activity of the glucocorticoid receptor
(GR), which is a member of the nuclear receptor family. In this study, we show that 14–3-3 …
Abstract
Proteins belonging to the 14–3-3 family interact with various regulatory proteins involved in cellular signaling, cell cycle regulation, or apoptosis. 14–3-3 proteins have been suggested to act by regulating the cytoplasmic/nuclear localization of their target proteins or by acting as molecular scaffolds or chaperones. We have previously shown that overexpression of 14–3-3 enhances the transcriptional activity of the glucocorticoid receptor (GR), which is a member of the nuclear receptor family. In this study, we show that 14–3-3 interacts with the nuclear receptor corepressor RIP140. In transfection assays, RIP140 antagonizes 14–3-3- enhanced GR transactivation. Using colocalization studies we demonstrate that 14–3-3 can export RIP140 out of the nucleus and, interestingly, can also change its intranuclear localization. Moreover, we also observed that 14–3-3 can bind various other nuclear receptors and cofactors. In summary, our findings suggest that 14–3-3-mediated intracellular relocalization of the GR corepressor RIP140 might be a novel mechanism to enhance glucocorticoid responsiveness of target genes. They furthermore indicate a more general role for 14–3-3 protein by influencing the nuclear availability of nuclear receptor-associated cofactors.
Oxford University Press