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Liu N, Qadri F, Busch H, Huegel S, Sihn G, Chuykin I, Hartmann E, Bader M, Rother F. Kpna6 deficiency causes infertility in male mice by disrupting spermatogenesis. Development 2021; 148:272018. [PMID: 34473250 PMCID: PMC8513612 DOI: 10.1242/dev.198374] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 08/18/2021] [Indexed: 11/20/2022]
Abstract
Spermatogenesis is driven by an ordered series of events, which rely on trafficking of specific proteins between nucleus and cytoplasm. The karyopherin α family of proteins mediates movement of specific cargo proteins when bound to karyopherin β. Karyopherin α genes have distinct expression patterns in mouse testis, implying they may have unique roles during mammalian spermatogenesis. Here, we use a loss-of-function approach to determine specifically the role of Kpna6 in spermatogenesis and male fertility. We show that ablation of Kpna6 in male mice leads to infertility and has multiple cumulative effects on both germ cells and Sertoli cells. Kpna6-deficient mice exhibit impaired Sertoli cell function, including loss of Sertoli cells and a compromised nuclear localization of the androgen receptor. Furthermore, our data demonstrate devastating defects on spermiogenesis, including incomplete sperm maturation and a massive reduction in sperm number, accompanied by disturbed histone-protamine exchange, differential localization of the transcriptional regulator BRWD1 and altered expression of RFX2 target genes. Our work uncovers an essential role of Kpna6 in spermatogenesis and, hence, in male fertility. Summary: Two different mouse models delineate the morphological and functional impact of Kpna6 on spermatogenesis and Sertoli cell function and show that this protein is crucial for fertility in male mice.
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Affiliation(s)
- Na Liu
- Max Delbrück Center for Molecular Medicine, Berlin 13125, Germany
| | | | - Hauke Busch
- Medical Systems Biology Division, Lübeck Institute of Experimental Dermatology and Institute for Cardiogenetics, University of Lübeck, Lübeck 23562, Germany
| | - Stefanie Huegel
- Max Delbrück Center for Molecular Medicine, Berlin 13125, Germany.,Institute for Biology, Center for Structural and Cellular Biology in Medicine, University of Lübeck, Lübeck 23562, Germany
| | - Gabin Sihn
- Max Delbrück Center for Molecular Medicine, Berlin 13125, Germany
| | - Ilya Chuykin
- Max Delbrück Center for Molecular Medicine, Berlin 13125, Germany.,Department of Cell Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Enno Hartmann
- Institute for Biology, Center for Structural and Cellular Biology in Medicine, University of Lübeck, Lübeck 23562, Germany
| | - Michael Bader
- Max Delbrück Center for Molecular Medicine, Berlin 13125, Germany.,Institute for Biology, Center for Structural and Cellular Biology in Medicine, University of Lübeck, Lübeck 23562, Germany
| | - Franziska Rother
- Max Delbrück Center for Molecular Medicine, Berlin 13125, Germany.,Institute for Biology, Center for Structural and Cellular Biology in Medicine, University of Lübeck, Lübeck 23562, Germany
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Dar JA, Masoodi KZ, Eisermann K, Isharwal S, Ai J, Pascal LE, Nelson JB, Wang Z. The N-terminal domain of the androgen receptor drives its nuclear localization in castration-resistant prostate cancer cells. J Steroid Biochem Mol Biol 2014; 143:473-80. [PMID: 24662325 PMCID: PMC4127361 DOI: 10.1016/j.jsbmb.2014.03.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Revised: 02/14/2014] [Accepted: 03/14/2014] [Indexed: 10/25/2022]
Abstract
Androgen-independent nuclear localization is required for androgen receptor (AR) transactivation in castration-resistant prostate cancer (CRPC) and should be a key step leading to castration resistance. However, mechanism(s) leading to androgen-independent AR nuclear localization are poorly understood. Since the N-terminal domain (NTD) of AR plays a role in transactivation under androgen-depleted conditions, we investigated the role of the NTD in AR nuclear localization in CRPC. Deletion mutagenesis was used to identify amino acid sequences in the NTD essential for its androgen-independent nuclear localization in C4-2, a widely used CRPC cell line. Deletion mutants of AR tagged with green fluorescent protein (GFP) at the 5'-end were generated and their signal distribution was investigated in C4-2 cells by fluorescent microscopy. Our results showed that the region of a.a. 294-556 was required for androgen-independent AR nuclear localization whereas a.a. 1-293 mediates Hsp90 regulation of AR nuclear localization in CRPC cells. Although the region of a.a. 294-556 does not contain a nuclear import signal, it was able to enhance DHT-induced import of the ligand binding domain (LBD). Also, transactivation of the NTD could be uncoupled from its modulation of AR nuclear localization in C4-2 cells. These observations suggest an important role of the NTD in AR intracellular trafficking and androgen-independent AR nuclear localization in CRPC cells.
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Affiliation(s)
- Javid A Dar
- Department of Urology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15232, United States; Central Laboratory College of Science, King Saud University, Riyadh KSA-11451, Saudi Arabia
| | - Khalid Z Masoodi
- Department of Urology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15232, United States
| | - Kurtis Eisermann
- Department of Urology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15232, United States
| | - Sudhir Isharwal
- Department of Urology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15232, United States
| | - Junkui Ai
- Department of Urology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15232, United States
| | - Laura E Pascal
- Department of Urology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15232, United States
| | - Joel B Nelson
- Department of Urology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15232, United States; University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA 15232, United States
| | - Zhou Wang
- Department of Urology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15232, United States; Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, United States; University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA 15232, United States.
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Wosnitzer MS, Mielnik A, Dabaja A, Robinson B, Schlegel PN, Paduch DA. Ubiquitin Specific Protease 26 (USP26) expression analysis in human testicular and extragonadal tissues indicates diverse action of USP26 in cell differentiation and tumorigenesis. PLoS One 2014; 9:e98638. [PMID: 24922532 PMCID: PMC4055479 DOI: 10.1371/journal.pone.0098638] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Accepted: 05/06/2014] [Indexed: 02/03/2023] Open
Abstract
Ubiquitin specific protease 26 (USP26), a deubiquitinating enzyme, is highly expressed early during murine spermatogenesis, in round spermatids, and at the blood-testis barrier. USP26 has also been recognized as a regulator of androgen receptor (AR) hormone-induced action involved in spermatogenesis and steroid production in in vitro studies. Prior mutation screening of USP26 demonstrated an association with human male infertility and low testosterone production, but protein localization and expression in the human testis has not been characterized previously. USP26 expression analysis of mRNA and protein was completed using murine and human testis tissue and human tissue arrays. USP26 and AR mRNA levels in human testis were quantitated using multiplex qRT-PCR. Immunofluorescence colocalization studies were performed with formalin-fixed/paraffin-embedded and frozen tissues using primary and secondary antibodies to detect USP26 and AR protein expression. Human microarray dot blots were used to identify protein expression in extra-gonadal tissues. For the first time, expression of USP26 and colocalization of USP26 with androgen receptor in human testis has been confirmed predominantly in Leydig cell nuclei, with less in Leydig cell cytoplasm, spermatogonia, primary spermatocytes, round spermatids, and Sertoli cells. USP26 likely affects regulatory proteins of early spermatogenesis, including androgen receptor with additional activity in round spermatids. This X-linked gene is not testis-specific, with USP26 mRNA and protein expression identified in multiple other human organ tissues (benign and malignant) including androgen-dependent tissues such as breast (myoepithelial cells and secretory luminal cells) and thyroid tissue (follicular cells). USP26/AR expression and interaction in spermatogenesis and androgen-dependent cancer warrants additional study and may prove useful in diagnosis and management of male infertility.
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Affiliation(s)
- Matthew S. Wosnitzer
- Department of Urology, Weill Cornell Medical College, New York, New York, United States of America
- * E-mail:
| | - Anna Mielnik
- Department of Urology, Weill Cornell Medical College, New York, New York, United States of America
| | - Ali Dabaja
- Department of Urology, Weill Cornell Medical College, New York, New York, United States of America
| | - Brian Robinson
- Department of Pathology, Weill Cornell Medical College, New York, New York, United States of America
| | - Peter N. Schlegel
- Department of Urology, Weill Cornell Medical College, New York, New York, United States of America
| | - Darius A. Paduch
- Department of Urology, Weill Cornell Medical College, New York, New York, United States of America
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4
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Kumar S, Tyagi RK. Androgen receptor association with mitotic chromatin - analysis with introduced deletions and disease-inflicting mutations. FEBS J 2012; 279:4598-614. [DOI: 10.1111/febs.12046] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Revised: 09/24/2012] [Accepted: 10/25/2012] [Indexed: 12/17/2022]
Affiliation(s)
- Sanjay Kumar
- Special Centre for Molecular Medicine; Jawaharlal Nehru University; New Delhi; India
| | - Rakesh K. Tyagi
- Special Centre for Molecular Medicine; Jawaharlal Nehru University; New Delhi; India
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5
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Qiu Y, Tanaka T, Nawata H, Yanase T. Dihydrotestosterone inhibits lectin-like oxidized-LDL receptor-1 expression in aortic endothelial cells via a NF-κB/AP-1-mediated mechanism. Endocrinology 2012; 153:3405-15. [PMID: 22597534 DOI: 10.1210/en.2011-1993] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The mechanisms involved in the antiatherosclerotic effects of androgens are unclear. Although lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) in endothelial cells plays critical roles in atherosclerosis, the effects of androgens on endothelial LOX-1 expression has not been examined. Therefore, to investigate the effects of dihydrotestosterone (DHT) on LOX-1 expression in rabbit aortic endothelial cells and cultured human aortic endothelial cells (HAEC), pellets containing DHT or placebo were s.c. implanted into 26 male New Zealand white rabbits at the time of castration or sham operation. The rabbits were then fed a high-cholesterol diet (HCD) for 2 wk. Microscopic examination of the aortic arch revealed that DHT significantly reduced HCD-induced LOX-1 expression in endothelial cells compared with placebo. In cultured HAEC, DHT at concentrations above 10(-9) to 10(-7) mol/liter inhibited TNFα-induced LOX-1 mRNA and protein expression. Deletion and mutation analysis of human LOX-1 promoter-luciferase constructs transfected into HAEC with an androgen receptor (AR) expression plasmid revealed that the 12-O-tetradecanoylphorbol-13-acetate (TPA) response element (TRE; nucleotides -60/-53) contributed to the inhibitory effects of DHT on TNFα-induced LOX-1 expression. Chromatin immunoprecipitation (ChIP) and re-ChIP assays revealed that TNFα- and TPA-dependent enrichment of p65 and phosphorylated c-Jun in the TRE chromatin region was inhibited by DHT-AR. Consistent with these results, DHT also suppressed TPA-induced expression of LOX-1. In conclusion, DHT exerts antiatherosclerotic effects by suppressing endothelial LOX-1 expression. This effect is partly mediated by the suppression of nuclear factor-κB- and activator protein 1-dependent activation of the LOX-1 promoter.
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Affiliation(s)
- Yang Qiu
- Department of Medicine and Bioregulatory Science, Graduate School of Medical Science, Kyushu University, Fukuoka 812-8582, Japan
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6
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Kawata H, Arai S, Nakagawa T, Ishikura N, Nishimoto A, Yoshino H, Shiraishi T, Tachibana K, Nakamura R, Sato H. Biological properties of androgen receptor pure antagonist for treatment of castration-resistant prostate cancer: optimization from lead compound to CH5137291. Prostate 2011; 71:1344-56. [PMID: 21308717 DOI: 10.1002/pros.21351] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2010] [Accepted: 01/06/2011] [Indexed: 11/09/2022]
Abstract
BACKGROUND Castration-resistant prostate cancer (CRPC) is still dependent on androgen receptor (AR) signaling. We previously reported that a novel nonsteroidal AR pure antagonist, CH4933468, which is a thiohydantoin derivative with a sulfonamide side chain, provided in vitro proof of concept but did not in vivo. METHODS We developed other derivatives, CH5137291, CH5138514, and CH5166623, and their pharmacological properties were compared with CH4933468 and bicalutamide. Agonist/antagonist activities in AR-mediated transactivation, cell proliferation against LNCaP and LNCaP-BC2, and AR translocation were evaluated. Agonist metabolite was monitored in liver microsomes and in pharmacokinetics experiments. Antitumor activities in CRPC xenograft models were examined using LNCaP-BC2 and VCaP-CRPC. RESULTS All CH compounds completely inhibited AR-mediated transactivation and proliferation of LNCaP and LNCaP-BC2. In contrast bicalutamide showed a partial inhibition of AR-mediated transactivation and a proliferation of LNCaP-BC2. AR translocation to nucleus was inhibited by CH compounds, but stimulated by bicalutamide. In the LNCaP-BC2 xenograft model, however, only CH5137291 showed significant inhibition of plasma PSA level and antitumor activity. The other three CH compounds were metabolized to their core structure which had agonist activity. CH5137291 also exhibited antitumor activity in a VCaP-CRPC xenograft model, but bicalutamide did not. CONCLUSIONS The molecular mechanism of the CH compounds, inhibition of AR translocation, was different from bicalutamide and this action could contribute to AR pure antagonist activity. Agonist metabolite diminished the antitumor activity of AR pure antagonist. CH5137291 exhibited antitumor activity in LNCaP-BC2 and VCaP-CRPC xenograft models, suggesting that the compound has potential for the treatment of CRPC.
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Affiliation(s)
- Hiromitsu Kawata
- Kamakura Research Laboratories, Chugai Pharmaceutical Co., Ltd., Kanagawa, Japan.
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7
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Corry GN, Raghuram N, Missiaen KK, Hu N, Hendzel MJ, Underhill DA. The PAX3 Paired Domain and Homeodomain Function as a Single Binding Module In Vivo to Regulate Subnuclear Localization and Mobility by a Mechanism That Requires Base-Specific Recognition. J Mol Biol 2010; 402:178-93. [DOI: 10.1016/j.jmb.2010.07.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2010] [Revised: 07/05/2010] [Accepted: 07/07/2010] [Indexed: 10/19/2022]
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8
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Itman C, Miyamoto Y, Young J, Jans D, Loveland K. Nucleocytoplasmic transport as a driver of mammalian gametogenesis. Semin Cell Dev Biol 2009; 20:607-19. [DOI: 10.1016/j.semcdb.2009.05.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2009] [Revised: 04/29/2009] [Accepted: 05/04/2009] [Indexed: 12/17/2022]
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9
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Lenie S, Smitz J. Functional AR signaling is evident in an in vitro mouse follicle culture bioassay that encompasses most stages of folliculogenesis. Biol Reprod 2008; 80:685-95. [PMID: 19074005 DOI: 10.1095/biolreprod.107.067280] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Androgens have distinct physiological functions within the ovary. The biological action of androgens is primarily exerted through transcriptional regulation by the nuclear androgen receptor (AR), but the molecular cascades governed by AR remain largely unknown. At present, there is imminent concern that environmental man-made chemicals with antiandrogenic properties, among others, are capable of modulating hormonal responses, thereby interfering with normal physiological processes that are critical to fertility. In the present study, we aimed to further characterize a standardized and reproducible follicle culture system in terms of AR expression during in vitro folliculogenesis to be able to use it as a bioassay to study effects of antiandrogens on follicular and oocyte growth, steroid secretion profile, and oocyte meiotic maturation capacity. Immunohistochemical analysis revealed that cytoplasmic AR protein was translocated to the nucleus of granulosa and theca cells in response to endogenous androgen production in theca cells during preantral follicular development. During the antral phase in vitro, AR was differentially expressed in mural and cumulus cells, implying an oocyte-mediated regulation. Treatment of follicles with hydroxyflutamide or bicalutamide, two model antiandrogenic compounds, resulted in reduced follicular growth during the preantral phase, altered steroidogenic environment, and arrest in oocyte meiotic maturation in response to human chorionic gonadotropin. Androgen receptor expression in the culture model corresponded well to what is described in vivo, and this system revealed several ovarian functions targeted by AR antagonists that can be further investigated using more in-depth molecular techniques.
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Affiliation(s)
- Sandy Lenie
- Follicle Biology Laboratory, Vrije Universiteit Brussel, Brussels, Belgium.
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10
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Fan W, Yanase T, Nishi Y, Chiba S, Okabe T, Nomura M, Yoshimatsu H, Kato S, Takayanagi R, Nawata H. Functional potentiation of leptin-signal transducer and activator of transcription 3 signaling by the androgen receptor. Endocrinology 2008; 149:6028-36. [PMID: 18703637 DOI: 10.1210/en.2008-0431] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Hypogonadism is associated with increased fat mass and dysregulation of metabolic homeostasis in men. Our previous study revealed that androgen receptor (AR)-null male mice (ARL-/Y) develop late-onset obesity and are leptin-resistant. The present study evaluated how hypothalamic AR contributes to central leptin-signal transducer and activator of transcription 3 (STAT3) signaling. We evaluated leptin action in wild-type and ARL-/Y mice, the anatomic co-relationship between AR and leptin signaling in the hypothalamus, and the effects of AR on leptin-mediated STAT3 transactivation and nuclear translocation. AR deletion in male mice results in a weaker leptin-induced suppression of food intake and body weight drop even before the onset of overt obesity. In wild-type male but not female mice, AR was highly expressed in various hypothalamic nuclei that also expressed the long-form leptin receptor (OBRB) and co-resided with OBRB directly in the arcuate neurons. In vitro, AR significantly enhanced STAT3-mediated transcription of leptin target genes including POMC and SOCS3. This effect relied on the AR N-terminal activation function-1 (AF-1) domain and was specific to AR in that none of the other sex steroid hormone receptors tested showed similar effects. AR enhanced the low concentrations of leptin-induced STAT3 nuclear translocation in vitro, and ARL-/Y mice receiving leptin had impaired STAT3 nuclear localization in the arcuate neurons. These findings indicate that AR in the hypothalamus functions as a regulator of central leptin-OBRB-STAT3 signaling and has a physiological role in energy homeostasis and metabolic regulation in male mice.
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Affiliation(s)
- WuQiang Fan
- Department of Medicine and Bioregulatory Science, Kyushu University, Fukuoka 812-8582, Japan
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Kaku N, Matsuda KI, Tsujimura A, Kawata M. Characterization of nuclear import of the domain-specific androgen receptor in association with the importin alpha/beta and Ran-guanosine 5'-triphosphate systems. Endocrinology 2008; 149:3960-9. [PMID: 18420738 PMCID: PMC2488236 DOI: 10.1210/en.2008-0137] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2008] [Accepted: 04/08/2008] [Indexed: 12/11/2022]
Abstract
Androgen induces androgen receptor (AR) nuclear import, which allows AR to act as a transcriptional factor and ultimately leads to biological activity. However, the mechanism of AR translocation to the nucleus is still unclear. In the present study, we assessed the nuclear import abilities of each domain of AR and their mechanisms related to Ran and importin alpha/beta using green fluorescent protein real-time imaging. The localization of AR to the nucleus in the absence and presence of ligands was dependent upon a complex interplay of the amino terminal transactivation domain (NTD), the DNA binding domain (DBD), and the ligand binding domain (LBD). NTD and DBD showed ligand-independent nuclear import ability, whereas LBD had ligand-dependent transport. In addition, AR deletion mutant lacking DBD was distributed in the cytoplasm regardless of ligand existence, suggesting that the remaining domains, NTD and LBD, are responsible for AR cytoplasmic localization. Cotransfection with a dominant negative form of Ran dramatically inhibited the nuclear import of all AR domains, and a dominant negative form of importin alpha prevented AR and DBD import. Importin beta-knockdown strongly blocked DBD import. These results indicate that there are two additional nuclear localization signals (NLSs) in the NTD and LBD, and there are distinct pathways used to attain domain-specific AR nuclear import: the NLS of DBD is Ran and importin alpha/beta-dependent, whereas the NLSs of NTD and LBD are Ran dependent but importin alpha/beta-independent. Our data suggest that the nuclear import of AR is regulated by the interplay between each domain of the AR.
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Affiliation(s)
- Natsuko Kaku
- Departments of Anatomy and Neurobiology, Research Institute for Geriatric and Neurobiological Diseases, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
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12
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Corry GN, Hendzel MJ, Underhill DA. Subnuclear localization and mobility are key indicators of PAX3 dysfunction in Waardenburg syndrome. Hum Mol Genet 2008; 17:1825-37. [PMID: 18325909 DOI: 10.1093/hmg/ddn076] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Mutations in the transcription factor PAX3 cause Waardenburg syndrome (WS) in humans and the mouse Splotch mutant, which display similar neural crest-derived defects. Previous characterization of disease-causing mutations revealed pleiotropic effects on PAX3 DNA binding and transcriptional activity. In this study, we evaluated the impact of disease alleles on PAX3 localization and mobility. Immunofluorescence analyses indicated that the majority of PAX3 occupies the interchromatin space, with only sporadic colocalization with sites of transcription. Interestingly, PAX3 disease alleles fell into two distinct categories when localization and dynamics in fluorescence recovery after photobleaching (FRAP) were assessed. The first group (class I), comprising N47H, G81A and V265F exhibit a diffuse distribution and markedly increased mobility when compared with wild-type PAX3. In contrast, the G42R, F45L, S84F, Y90H and R271G mutants (class II) display evidence of subnuclear compartmentalization and mobility intermediate between wild-type PAX3 and class I proteins. However, unlike class I mutants, which retain DNA binding, class II proteins are deficient for this activity, indicating that DNA binding is not a primary determinant of PAX3 distribution and movement. Importantly, class I properties prevail when combined with a class II mutation, which taken with the proximity of the two mutant classes within the PAX3 protein, suggests class I mutants act by perturbing PAX3 conformation. Together, these results establish that altered localization and dynamics play a key role in PAX3 dysfunction and that loss of the underlying determinants represents the principal defect for a subset of Waardenburg mutations.
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Affiliation(s)
- Gareth N Corry
- Department of Medical Genetics, University of Alberta, Edmonton, Alberta, Canada
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Cutress ML, Whitaker HC, Mills IG, Stewart M, Neal DE. Structural basis for the nuclear import of the human androgen receptor. J Cell Sci 2008; 121:957-68. [PMID: 18319300 DOI: 10.1242/jcs.022103] [Citation(s) in RCA: 153] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Ligand-dependent nuclear import is crucial for the function of the androgen receptor (AR) in both health and disease. The unliganded AR is retained in the cytoplasm but, on binding 5alpha-dihydrotestosterone, it translocates into the nucleus and alters transcription of its target genes. Nuclear import of AR is mediated by the nuclear import factor importin-alpha, which functions as a receptor that recognises and binds to specific nuclear localisation signal (NLS) motifs on cargo proteins. We show here that the AR binds to importin-alpha directly, albeit more weakly than the NLS of SV40 or nucleoplasmin. We describe the 2.6-angstroms-resolution crystal structure of the importin-alpha-AR-NLS complex, and show that the AR binds to the major NLS-binding site on importin-alpha in a manner different from most other NLSs. Finally, we have shown that pathological mutations within the NLS of AR that are associated with prostate cancer and androgen-insensitivity syndrome reduce the binding affinity to importin-alpha and, subsequently, retard nuclear import; surprisingly, however, the transcriptional activity of these mutants varies widely. Thus, in addition to its function in the nuclear import of AR, the NLS in the hinge region of AR has a separate, quite distinct role on transactivation, which becomes apparent once nuclear import has been achieved.
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Affiliation(s)
- Mark L Cutress
- Uro-Oncology Research Group, Cancer Research UK Cambridge Research Institute, Robinson Way, Cambridge, CB2 0RE, UK
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14
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Kawate H, Wu Y, Ohnaka K, Takayanagi R. Mutual transactivational repression of Runx2 and the androgen receptor by an impairment of their normal compartmentalization. J Steroid Biochem Mol Biol 2007; 105:46-56. [PMID: 17627815 DOI: 10.1016/j.jsbmb.2006.11.020] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2006] [Accepted: 11/08/2006] [Indexed: 02/03/2023]
Abstract
Steroid hormones play important roles not only in the reproductive system but also in bone metabolism. We examined the functional relationship between steroid hormone receptors and the Runx2 transcription factor that is essential for osteoblast differentiation and proliferation. A functional reporter assay using promoters carrying steroid hormone-responsive elements revealed that Runx2 suppressed ligand-dependent transcriptional activation mediated by receptors. To examine intracellular localization of these proteins, a three-dimensional imaging study was performed by laser scanning confocal microscopy of green fluorescent protein (GFP)-fused proteins. As previously reported, ligand-bound human androgen receptor (AR) was translocated from the cytoplasm to the nucleus and formed subnuclear fine foci. Coexpression of human Runx2 disrupted the AR subnuclear fine foci formation, and the intranuclear fluorescent pattern of AR became similar to that of Runx2. On the other hand, ligand-bound ARs repressed the Runx2-mediated transactivation function. Runx2 was also extracted from its original compartment by ligand-bound ARs. These results suggest that both Runx2 and ARs repress the transactivation function of the other protein by extracting it from its original compartment. The AR and Runx2 may play a mutual role in transcriptional activation in osteoblasts.
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Affiliation(s)
- Hisaya Kawate
- Department of Geriatric Medicine, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
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15
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Sun K, Montana V, Chellappa K, Brelivet Y, Moras D, Maeda Y, Parpura V, Paschal BM, Sladek FM. Phosphorylation of a conserved serine in the deoxyribonucleic acid binding domain of nuclear receptors alters intracellular localization. Mol Endocrinol 2007; 21:1297-311. [PMID: 17389749 DOI: 10.1210/me.2006-0300] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Nuclear receptors (NRs) are a superfamily of transcription factors whose genomic functions are known to be activated by lipophilic ligands, but little is known about how to deactivate them or how to turn on their nongenomic functions. One obvious mechanism is to alter the nuclear localization of the receptors. Here, we show that protein kinase C (PKC) phosphorylates a highly conserved serine (Ser) between the two zinc fingers of the DNA binding domain of orphan receptor hepatocyte nuclear factor 4alpha (HNF4alpha). This Ser (S78) is adjacent to several positively charged residues (Arg or Lys), which we show here are involved in nuclear localization of HNF4alpha and are conserved in nearly all other NRs, along with the Ser/threonine (Thr). A phosphomimetic mutant of HNF4alpha (S78D) reduced DNA binding, transactivation ability, and protein stability. It also impaired nuclear localization, an effect that was greatly enhanced in the MODY1 mutant Q268X. Treatment of the hepatocellular carcinoma cell line HepG2 with PKC activator phorbol 12-myristate 13-acetate also resulted in increased cytoplasmic localization of HNF4alpha as well as decreased endogenous HNF4alpha protein levels in a proteasome-dependent fashion. We also show that PKC phosphorylates the DNA binding domain of other NRs (retinoic acid receptor alpha, retinoid X receptor alpha, and thyroid hormone receptor beta) and that phosphomimetic mutants of the same Ser/Thr result in cytoplasmic localization of retinoid X receptor alpha and peroxisome proliferator-activated receptor alpha. Thus, phosphorylation of this conserved Ser between the two zinc fingers may be a common mechanism for regulating the function of NRs.
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Affiliation(s)
- Kai Sun
- Environmental Toxicology Graduate Program, University of California, Riverside, California 92521, USA
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16
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Lu NZ, Wardell SE, Burnstein KL, Defranco D, Fuller PJ, Giguere V, Hochberg RB, McKay L, Renoir JM, Weigel NL, Wilson EM, McDonnell DP, Cidlowski JA. International Union of Pharmacology. LXV. The pharmacology and classification of the nuclear receptor superfamily: glucocorticoid, mineralocorticoid, progesterone, and androgen receptors. Pharmacol Rev 2007; 58:782-97. [PMID: 17132855 DOI: 10.1124/pr.58.4.9] [Citation(s) in RCA: 272] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
MESH Headings
- Animals
- Hormone Antagonists/adverse effects
- Hormone Antagonists/therapeutic use
- Humans
- Ligands
- Mutation
- Receptors, Androgen/genetics
- Receptors, Androgen/physiology
- Receptors, Cytoplasmic and Nuclear/classification
- Receptors, Cytoplasmic and Nuclear/genetics
- Receptors, Cytoplasmic and Nuclear/physiology
- Receptors, Glucocorticoid/genetics
- Receptors, Glucocorticoid/physiology
- Receptors, Mineralocorticoid/genetics
- Receptors, Mineralocorticoid/physiology
- Receptors, Progesterone/genetics
- Receptors, Progesterone/physiology
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Affiliation(s)
- Nick Z Lu
- Molecular Endocrinology Group, Laboratory of Signal Transduction, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina 27709, USA
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17
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Arnett-Mansfield RL, Graham JD, Hanson AR, Mote PA, Gompel A, Scurr LL, Gava N, de Fazio A, Clarke CL. Focal subnuclear distribution of progesterone receptor is ligand dependent and associated with transcriptional activity. Mol Endocrinol 2006; 21:14-29. [PMID: 17021053 DOI: 10.1210/me.2006-0041] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The progesterone receptor (PR) is a critical mediator of progesterone action in the female reproductive system. Expressed in the human as two proteins, PRA and PRB, the receptor is a ligand-activated nuclear transcription factor that regulates transcription by interaction with protein cofactors and binding to specific response elements in target genes. We previously reported that PR was located in discrete subnuclear foci in human endometrium. In this study, we investigated the role of ligand in the formation of PR foci and their association with transcriptional activity. PR foci were detected in mouse uterus and normal human breast tissues and were more abundant when circulating progesterone was high. In human malignant tissues, PR foci were aberrant: foci were larger in endometrial cancers than in normal endometrium, and in breast cancers hormone-dependence was decreased. Chromatin disruption also increased foci size and decreased ligand dependence, suggesting that altered nuclear architecture may contribute to the aberrant PR foci observed in endometrial and breast cancers. In breast cancer cells, movement of PR into foci required exposure to ligand and was blocked by transcriptional inhibitors and by prolonged inhibition of proteasomal degradation. Foci contained PR dimers, and fluorescence resonance energy transfer demonstrated that PR foci contained the highest concentration of receptor dimers in the nucleus. PR in foci colocalized with transcription factors and nascent RNA transcripts only in the presence of ligand, and inhibition of coactivator recruitment inhibited PR foci formation. The demonstration that focal distribution of PR within the nucleus is associated with transcription suggests a link between the subnuclear distribution of PR and its transcriptional activity that is likely to be important for normal cellular function of PR.
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18
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Moretti C, Odorisio T, Geremia R, Grimaldi P. An uncommon large deletion in the androgen-receptor gene in a XY female with complete androgen insensitivity syndrome. J Endocrinol Invest 2006; 29:457-61. [PMID: 16794370 DOI: 10.1007/bf03344130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Androgen insensitivity is a disorder characterized by an abnormal male sexual development, in which the androgen action is impaired due to structural defects in the androgen receptor gene. We report a case of a 46,XY subject with female phenotype (normal breast and external genitalia) lacking sexual hair, affected with primary amenorrhea. In this patient, we found a deletion of a large region of the androgen receptor gene encoding the steroid-binding domain of the protein, causing a complete inability to bind the androgens. This uncommon molecular defect impaired the expression of androgen-dependent genes inducing the female phenotype.
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Affiliation(s)
- C Moretti
- Unit of Endocrinology, Department of Internal Medicine, University of Tor Vergata, Fatebenefratelli Hospital, Isola Tiberina, 00186 Rome, Italy.
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19
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Tao RH, Kawate H, Ohnaka K, Ishizuka M, Hagiwara H, Takayanagi R. Opposite effects of alternative TZF spliced variants on androgen receptor. Biochem Biophys Res Commun 2006; 341:515-21. [PMID: 16446156 DOI: 10.1016/j.bbrc.2005.12.213] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2005] [Accepted: 12/29/2005] [Indexed: 11/16/2022]
Abstract
We previously demonstrated that testicular zinc-finger protein (TZF) was a corepressor of the androgen receptor (AR). In the present study, we further showed that TZF-L, an alternative spliced variant of TZF, enhanced transactivation function of AR. Deletion analysis of TZF-L revealed that its N-terminus, which almost corresponded to that of TZF, but not its C-terminus was able to interact with AR. Additional analysis suggested that TZF and TZF-L were able to form both homodimers and heterodimers. TZF-L inhibited the homodimer formation of TZF and the intranuclear dot formation of TZF. We propose that in the unique regulation system of AR-mediated transactivation, two spliced isoforms of TZF act as coactivator and corepressor, respectively.
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Affiliation(s)
- Rong-Hua Tao
- Department of Geriatric Medicine, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka 812-8582, Japan
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