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Timmermans S, Verhoog NJD, Van Looveren K, Dewaele S, Hochepied T, Eggermont M, Gilbert B, Boerema-de Munck A, Vanderhaeghen T, Vanden Berghe J, Garcia Gonzalez N, Vandewalle J, Bloch Y, Provost M, Savvides SN, De Bosscher K, Declercq W, Rottier RJ, Louw A, Libert C. Point mutation I634A in the glucocorticoid receptor causes embryonic lethality by reduced ligand binding. J Biol Chem 2022; 298:101574. [PMID: 35007536 PMCID: PMC8808175 DOI: 10.1016/j.jbc.2022.101574] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 12/30/2021] [Accepted: 12/31/2021] [Indexed: 12/23/2022] Open
Abstract
The glucocorticoid (GC) receptor (GR) is essential for normal development and in the initiation of inflammation. Healthy GRdim/dim mice with reduced dimerization propensity due to a point mutation (A465T) at the dimer interface of the GR DNA-binding domain (DBD) (here GRD/D) have previously helped to define the functions of GR monomers and dimers. Since GRD/D retains residual dimerization capacity, here we generated the dimer-nullifying double mutant GRD+L/D+L mice, featuring an additional mutation (I634A) in the ligand-binding domain (LBD) of GR. These mice are perinatally lethal, as are GRL/L mice (these mice have the I634A mutation but not the A465T mutation), displaying improper lung and skin formation. Using embryonic fibroblasts, high and low doses of dexamethasone (Dex), nuclear translocation assays, RNAseq, dimerization assays, and ligand-binding assays (and Kd values), we found that the lethal phenotype in these mice is due to insufficient ligand binding. These data suggest there is some correlation between GR dimerization potential and ligand affinity. We conclude that even a mutation as subtle as I634A, at a position not directly involved in ligand interactions sensu stricto, can still influence ligand binding and have a lethal outcome.
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Affiliation(s)
- Steven Timmermans
- VIB Center for Inflammation Research, VIB, Ghent, Belgium; Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | | | - Kelly Van Looveren
- VIB Center for Inflammation Research, VIB, Ghent, Belgium; Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Sylviane Dewaele
- VIB Center for Inflammation Research, VIB, Ghent, Belgium; Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Tino Hochepied
- VIB Center for Inflammation Research, VIB, Ghent, Belgium; Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Melanie Eggermont
- VIB Center for Inflammation Research, VIB, Ghent, Belgium; Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Barbara Gilbert
- VIB Center for Inflammation Research, VIB, Ghent, Belgium; Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Anne Boerema-de Munck
- Department of Pediatric Surgery, Erasmus Medical Center, Sophia Children's Hospital, Rotterdam, The Netherlands; Department of Cell Biology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Tineke Vanderhaeghen
- VIB Center for Inflammation Research, VIB, Ghent, Belgium; Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Joke Vanden Berghe
- VIB Center for Inflammation Research, VIB, Ghent, Belgium; Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Natalia Garcia Gonzalez
- VIB Center for Inflammation Research, VIB, Ghent, Belgium; Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Jolien Vandewalle
- VIB Center for Inflammation Research, VIB, Ghent, Belgium; Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Yehudi Bloch
- VIB Center for Inflammation Research, VIB, Ghent, Belgium; Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
| | - Mathias Provost
- VIB Center for Inflammation Research, VIB, Ghent, Belgium; Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
| | - Savvas N Savvides
- VIB Center for Inflammation Research, VIB, Ghent, Belgium; Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
| | - Karolien De Bosscher
- Department of Biochemistry, Ghent University, Ghent, Belgium; Receptor Research Laboratories, Nuclear Receptor Lab, Medical Biotechnology Center, VIB, Ghent, Belgium
| | - Wim Declercq
- VIB Center for Inflammation Research, VIB, Ghent, Belgium; Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Robbert J Rottier
- Department of Pediatric Surgery, Erasmus Medical Center, Sophia Children's Hospital, Rotterdam, The Netherlands; Department of Cell Biology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Ann Louw
- Department of Biochemistry, Stellenbosch University, Stellenbosch, South Africa
| | - Claude Libert
- VIB Center for Inflammation Research, VIB, Ghent, Belgium; Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium.
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Li F, Yu S, Huang X, Dong C, Ren J. Studying Homo-oligomerization and Hetero-oligomerization of MDMX and MDM2 Proteins in Single Living Cells by Using In Situ Fluorescence Correlation Spectroscopy. Biochemistry 2021; 60:1498-1505. [PMID: 33870698 DOI: 10.1021/acs.biochem.1c00153] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Protein oligomerization plays a very important role in many physiological processes. p53 acts as a key tumor suppressor by regulating cell cycle arrest, DNA repair, and apoptosis, and its antitumor activity is regulated by the hetero- and homo-oligomerization of MDMX and MDM2 proteins. So far, some traditional methods have been utilized to study the oligomerization of MDMX and MDM2 in vitro, but they have not clarified some controversial issues or whether the extracellular results can represent the intracellular results. Here, we put forward an in situ method for studying protein homo- and hetero-oligomerization in single living cells by using fluorescence correlation spectroscopy. In this study, MDMX and MDM2 were labeled with fluorescent proteins using lentiviral transfection. Autocorrelation spectroscopy and cross-correlation spectroscopy methods were used to study the oligomerization of MDMX and MDM2 in situ and the effect of regulation of MDMX oligomerization on p53-MDMX interactions in single living cells. We observed the homo- and hetero-oligomerization of MDMX and MDM2 in living cells. Meanwhile, the levels of the homo-oligomers of MDMX and MDM2 were increased due to the lack of hetero-oligomerization. Finally, the binding affinity of MDMX for p53 was improved with an increase in the level of MDMX hetero-oligomerization.
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Affiliation(s)
- Fucai Li
- School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China
| | - Shengrong Yu
- School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China
| | - Xiangyi Huang
- School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China
| | - Chaoqing Dong
- School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China
| | - Jicun Ren
- School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China
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Phasing the intranuclear organization of steroid hormone receptors. Biochem J 2021; 478:443-461. [DOI: 10.1042/bcj20200883] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 12/28/2020] [Accepted: 01/07/2021] [Indexed: 12/15/2022]
Abstract
Steroid receptors (SRs) encompass a family of transcription factors that regulate the expression of thousands of genes upon binding to steroid hormones and include the glucocorticoid, androgen, progesterone, estrogen and mineralocorticoid receptors. SRs control key physiological and pathological processes, thus becoming relevant drug targets. As with many other nuclear proteins, hormone-activated SRs concentrate in multiple discrete foci within the cell nucleus. Even though these foci were first observed ∼25 years ago, their exact structure and function remained elusive. In the last years, new imaging methodologies and theoretical frameworks improved our understanding of the intranuclear organization. These studies led to a new paradigm stating that many membraneless nuclear compartments, including transcription-related foci, form through a liquid–liquid phase separation process. These exciting ideas impacted the SR field by raising the hypothesis of SR foci as liquid condensates involved in transcriptional regulation. In this work, we review the current knowledge about SR foci formation under the light of the condensate model, analyzing how these structures may impact SR function. These new ideas, combined with state-of-the-art techniques, may shed light on the biophysical mechanisms governing the formation of SR foci and the biological function of these structures in normal physiology and disease.
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Preuss JM, Burret U, Vettorazzi S. Multiplex Fluorescent Bead-Based Immunoassay for the Detection of Cytokines, Chemokines, and Growth Factors. Methods Mol Biol 2021; 2261:247-262. [PMID: 33420994 DOI: 10.1007/978-1-0716-1186-9_15] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The comprehensive analysis of serum cytokine levels can be challenging due to low sample volumes and time consuming when using single-target methods like enzyme-linked immunosorbent assay (ELISA). Bead-based detection systems allow the simultaneous detection of multiple analytes using minimal sample volumes. Here we describe the use of a multiplex cytokine, chemokine, and growth factor assay for mouse cytokines in a 96-well format. This assay is based on antibody-coupled fluorescent magnetic beads combined with biotinylated secondary detection antibody followed by fluorescent-tagged streptavidin in a sandwich-like composition. Final assay readout provides the concentrations of 23 different cytokines, chemokines, and growth factors in up to 76 samples.
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Affiliation(s)
- Jonathan M Preuss
- Institute of Comparative Molecular Endocrinology (CME), Ulm University, Ulm, Germany.
| | - Ute Burret
- Institute of Comparative Molecular Endocrinology (CME), Ulm University, Ulm, Germany
| | - Sabine Vettorazzi
- Institute of Comparative Molecular Endocrinology (CME), Ulm University, Ulm, Germany.
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Louw A. GR Dimerization and the Impact of GR Dimerization on GR Protein Stability and Half-Life. Front Immunol 2019; 10:1693. [PMID: 31379877 PMCID: PMC6653659 DOI: 10.3389/fimmu.2019.01693] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 07/08/2019] [Indexed: 12/14/2022] Open
Abstract
Pharmacologically, glucocorticoids, which mediate their effects via the glucocorticoid receptor (GR), are a most effective therapy for inflammatory diseases despite the fact that chronic use causes side-effects and acquired GC resistance. The design of drugs with fewer side-effects and less potential for the development of resistance is therefore considered crucial for improved therapy. Dimerization of the GR is an integral step in glucocorticoid signaling and has been identified as a possible molecular site to target for drug development of anti-inflammatory drugs with an improved therapeutic index. Most of the current understanding regarding the role of GR dimerization in GC signaling derives for dimerization deficient mutants, although the role of ligands biased toward monomerization has also been described. Even though designing for loss of dimerization has mostly been applied for reduction of side-effect profile, designing for loss of dimerization may also be a fruitful strategy for the development of GC drugs with less potential to develop GC resistance. GC-induced resistance affects up to 30% of users and is due to a reduction in the GR functional pool. Several molecular mechanisms of GC-mediated reductions in GR pool have been described, one of which is the autologous down-regulation of GR density by the ubiquitin-proteasome-system (UPS). Loss of GR dimerization prevents autologous down-regulation of the receptor through modulation of interactions with components of the UPS and post-translational modifications (PTMs), such as phosphorylation, which prime the GR for degradation. Rational design of conformationally biased ligands that select for a monomeric GR conformation, which increases GC sensitivity through improving GR protein stability and increasing half-life, may be a productive avenue to explore. However, potential drawbacks to this approach should be considered as well as the advantages and disadvantages in chronic vs. acute treatment regimes.
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Affiliation(s)
- Ann Louw
- Department of Biochemistry, Stellenbosch University, Stellenbosch, South Africa
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