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The glucocorticoid receptor (GR) is a ligand-activated transcription factor. In this study, we used the yeast two-hybrid system to isolate cDNAs encoding proteins that interact with the human GR ligand-binding domain (LBD) in a ligand-dependent manner. One isolated cDNA from a HeLa cell library encoded the COOH-terminal portion of the -isoform of the 14-3-3 protein (residues 187-246). Glucocorticoid agonists, triamcinolone acetonide and dexamethasone, induced the GR LBD/14-3-3 protein fragment interaction, but an antagonist, RU486, did not. Glutathione S-transferase pull-down experiments in vitro showed that full-length 14-3-3 protein also interacted with the activated GR. Transient transfection studies using COS-7 cells revealed a stimulatory effect of 14-3-3 protein on transcriptional activation by the GR. The 14-3-3 family members have recently been found to associate with a number of important signaling proteins, such as protein kinase C and Raf-1, as functional modulators. Our findings suggest a novel regulatory role of 14-3-3 protein in GRmediated signaling pathways and also point to a mechanism whereby GR may cross-talk with other signal transduction systems.

In this project, the evidence for the non-monotonic dose-response (NMDR) hypothesis was evaluated by critically reviewing the scientific peer-reviewed literature in the last decade (from 2002 onwards) for substances in the area of food safety. The project was performed according to the systematic review methodology. After a detailed analysis of previous reports published on the issue of NMDRs, a literature search was performed to identify in vivo, in vitro and epidemiological/human studies containing evidence for potential NMDRs. Inclusion and reliability criteria were defined and used to select relevant and reliable studies. Of studies with at least 5 dose groups, dose-response datasets were extracted and analysed by PROAST software package. The resulting dose-response results were evaluated for possible evidence of NMDR by applying six checkpoints. These checkpoints addressed both random and non-random errors. The plausibility of NMDRs was assessed based on the number of fulfilled checkpoints. In total, 202 in vivo datasets (from 49 studies), 311 in vitro datasets (from 91 studies) and 9 epidemiological/human datasets (from 2 studies) were identified. Among them, 179 in vivo and 13 in vitro dose-response datasets were analysed and evaluated using the checkpoints. For 23 in vivo datasets there were data limitations, which made the data unsuitable for dose-response analysis. For the in vitro studies, only continuous dose-response datasets presented in tables were analysed. None of the datasets from epidemiological/human studies could be analysed (one of the epidemiological studies was not analysed due to quantal data and the other due to data limitations).In most of the in vivo datasets, the apparent NMDR might have been caused by a single outlying dose group. In total, only 10 out of the 179 in vivo datasets fulfilled all six checkpoints. The latter datasets included studies on the substances quercetin, resveratrol, alpha-benzene hexachloride, and methylmercury. Review of NMDR of substances for HRA ContributorsAGES: Boehm T., Coja T., Hrdina-Zoedl B., Pacher-Zavisin M., Steinparzer R.ANSES: Charles S., Gouze M.E., Guillou P., Lehegarat L., Manière I., Ormsby J.N., Papadopoulos A., Printemps N., Roudot A.C.RIVM: Smeet E. Acknowledgements:RIVM: Ossendorp B., Vermeire T.IMM: Gornitzki C., Moberg K., Karolinska Institutet University Library Reproduction is authorised provided the source is acknowledged.Permission to reproduce the images must be sought directly from the copyright holder SummaryThe overall objective of this project was to evaluate the evidence for the non-monotonic doseresponse (NMDR) hypothesis by critically reviewing the scientific peer-reviewed literature in the last decade (from 2002 onwards) for substances (other than essential nutrients) in the area of food safety. MethodologyThe project was based on a systematic review including the steps of Preparing the review (review protocol, review question and criteria for study eligibility), Searching for research studies, Selecting the stu...

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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.