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Abstract
Spindle poles are defined by centrosomes; therefore, an abnormal number or defective structural organization of centrosomes can lead to loss of spindle bipolarity and genetic integrity. Previously, we showed that Tpr (translocated promoter region), a component of the nuclear pore complex (NPC), interacts with Mad1 and dynein to promote proper chromosome segregation during mitosis. Tpr also associates with p53 to induce autophagy. Here, we report that Tpr depletion induces mitotic catastrophe and enhances the rate of tetraploidy and polyploidy. Mechanistically, Tpr interacts, via its central domain, with Aurora A but not Aurora B kinase. In Tpr-depleted cells, the expression levels, centrosomal localization and phosphorylation of Aurora A were all reduced. Surprisingly, an Aurora A inhibitor, Alisertib (MLN8237), also disrupted centrosomal localization of Tpr and induced mitotic catastrophe and cell death in a time- and dose-dependent manner. Strikingly, over-expression of Aurora A disrupted Tpr centrosomal localization only in cells with supernumerary centrosomes but not in bipolar cells. Our results highlight the mutual regulation between Tpr and Aurora A and further confirm the importance of nucleoporin function in spindle pole organization, bipolar spindle assembly, and mitosis; functions that are beyond the conventional nucleocytoplasmic transport and NPC structural roles of nucleoporins. Furthermore, the central coiled-coil domain of Tpr binds to and sequesters extra Aurora A to safeguard bipolarity. This Tpr domain merits further investigation for its ability to inhibit Aurora kinase and as a potential therapeutic agent in cancer treatment.
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Affiliation(s)
- Akiko Kobayashi
- a Laboratory of Molecular and Cellular Biology; Department of Biology ; Faculty of Natural Systems; Kanazawa University ; Kanazawa , Ishikawa , Japan
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Smith AK, Conneely KN, Kilaru V, Mercer KB, Weiss TE, Bradley B, Tang Y, Gillespie CF, Cubells JF, Ressler KJ. Differential immune system DNA methylation and cytokine regulation in post-traumatic stress disorder. Am J Med Genet B Neuropsychiatr Genet 2011; 156B:700-8. [PMID: 21714072 PMCID: PMC3292872 DOI: 10.1002/ajmg.b.31212] [Citation(s) in RCA: 235] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2011] [Accepted: 05/31/2011] [Indexed: 12/15/2022]
Abstract
DNA methylation may mediate persistent changes in gene function following chronic stress. To examine this hypothesis, we evaluated African American subjects matched by age and sex, and stratified into four groups by post-traumatic stress disorder (PTSD) diagnosis and history of child abuse. Total Life Stress (TLS) was also assessed in all subjects. We evaluated DNA extracted from peripheral blood using the HumanMethylation27 BeadChip and analyzed both global and site-specific methylation. Methylation levels were examined for association with PTSD, child abuse history, and TLS using a linear mixed model adjusted for age, sex, and chip effects. Global methylation was increased in subjects with PTSD. CpG sites in five genes (TPR, CLEC9A, APC5, ANXA2, and TLR8) were differentially methylated in subjects with PTSD. Additionally, a CpG site in NPFFR2 was associated with TLS after adjustment for multiple testing. Notably, many of these genes have been previously associated with inflammation. Given these results and reports of immune dysregulation associated with trauma history, we compared plasma cytokine levels in these subjects and found IL4, IL2, and TNFα levels associated with PTSD, child abuse, and TLS. Together, these results suggest that psychosocial stress may alter global and gene-specific DNA methylation patterns potentially associated with peripheral immune dysregulation. Our results suggest the need for further research on the role of DNA methylation in stress-related illnesses.
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Affiliation(s)
- Alicia K. Smith
- Department of Psychiatry & Behavioral Sciences, Emory University School of Medicine, Atlanta, Georgia
| | - Karen N. Conneely
- Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia
| | - Varun Kilaru
- Department of Psychiatry & Behavioral Sciences, Emory University School of Medicine, Atlanta, Georgia
| | | | - Tamara E. Weiss
- Department of Psychiatry & Behavioral Sciences, Emory University School of Medicine, Atlanta, Georgia
| | | | - Yilang Tang
- Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia
| | - Charles F. Gillespie
- Department of Psychiatry & Behavioral Sciences, Emory University School of Medicine, Atlanta, Georgia
| | - Joseph F. Cubells
- Department of Psychiatry & Behavioral Sciences, Emory University School of Medicine, Atlanta, Georgia,Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia
| | - Kerry J. Ressler
- Department of Psychiatry & Behavioral Sciences, Emory University School of Medicine, Atlanta, Georgia,Howard Hughes Medical Institute, Maryland,Yerkes National Primate Research Center, Atlanta, Georgia,Correspondence to: Kerry J. Ressler, M.D., Ph.D., Department of Psychiatry and Behavioral Sciences, Yerkes Research Center, Emory University, 954 Gatewood Dr, Atlanta, GA 30329.
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Coyle JH, Bor YC, Rekosh D, Hammarskjold ML. The Tpr protein regulates export of mRNAs with retained introns that traffic through the Nxf1 pathway. RNA 2011; 17:1344-56. [PMID: 21613532 PMCID: PMC3138570 DOI: 10.1261/rna.2616111] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Accepted: 04/18/2011] [Indexed: 05/22/2023]
Abstract
Post-transcriptional regulation of mRNA includes restriction mechanisms to prevent export and expression of mRNAs that are incompletely spliced. Here we present evidence that the mammalian protein Tpr is involved in this restriction. To study the role of Tpr in export of mRNA with retained introns, we used reporters in which the mRNA was exported either via the Nxf1/Nxt1 pathway using a CTE or via the Crm1 pathway using Rev/RRE. Our data show that even modest knockdown of Tpr using RNAi leads to a significant increase in export and translation from the mRNA containing the CTE. In contrast, Tpr perturbation has no effect on export of mRNA containing the RRE, either in the absence or presence of Rev. Also, no effects were observed on export of a completely spliced mRNA. Taken together, our results indicate that Tpr plays an important role in quality control of mRNA trafficked on the Nxf1 pathway.
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Affiliation(s)
- John H. Coyle
- Myles H. Thaler Center for AIDS and Human Retrovirus Research and Department of Microbiology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Yeou-Cherng Bor
- Myles H. Thaler Center for AIDS and Human Retrovirus Research and Department of Microbiology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - David Rekosh
- Myles H. Thaler Center for AIDS and Human Retrovirus Research and Department of Microbiology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Marie-Louise Hammarskjold
- Myles H. Thaler Center for AIDS and Human Retrovirus Research and Department of Microbiology, University of Virginia, Charlottesville, Virginia 22908, USA
- Corresponding author.E-mail .
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Krull S, Dörries J, Boysen B, Reidenbach S, Magnius L, Norder H, Thyberg J, Cordes VC. Protein Tpr is required for establishing nuclear pore-associated zones of heterochromatin exclusion. EMBO J 2010; 29:1659-73. [PMID: 20407419 PMCID: PMC2876962 DOI: 10.1038/emboj.2010.54] [Citation(s) in RCA: 127] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2009] [Accepted: 03/09/2010] [Indexed: 12/21/2022] Open
Abstract
Amassments of heterochromatin in somatic cells occur in close contact with the nuclear envelope (NE) but are gapped by channel- and cone-like zones that appear largely free of heterochromatin and associated with the nuclear pore complexes (NPCs). To identify proteins involved in forming such heterochromatin exclusion zones (HEZs), we used a cell culture model in which chromatin condensation induced by poliovirus (PV) infection revealed HEZs resembling those in normal tissue cells. HEZ occurrence depended on the NPC-associated protein Tpr and its large coiled coil-forming domain. RNAi-mediated loss of Tpr allowed condensing chromatin to occur all along the NE's nuclear surface, resulting in HEZs no longer being established and NPCs covered by heterochromatin. These results assign a central function to Tpr as a determinant of perinuclear organization, with a direct role in forming a morphologically distinct nuclear sub-compartment and delimiting heterochromatin distribution.
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Affiliation(s)
- Sandra Krull
- Max-Planck-Institut für Biophysikalische Chemie, Göttingen, Germany
- Zentrum für Molekulare Biologie der Universität Heidelberg, Heidelberg, Germany
| | - Julia Dörries
- Max-Planck-Institut für Biophysikalische Chemie, Göttingen, Germany
| | - Björn Boysen
- Zentrum für Molekulare Biologie der Universität Heidelberg, Heidelberg, Germany
| | - Sonja Reidenbach
- Zentrum für Molekulare Biologie der Universität Heidelberg, Heidelberg, Germany
| | - Lars Magnius
- Department of Virology, Swedish Institute for Infectious Disease Control, Solna, Sweden
| | - Helene Norder
- Department of Virology, Swedish Institute for Infectious Disease Control, Solna, Sweden
| | - Johan Thyberg
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Volker C Cordes
- Max-Planck-Institut für Biophysikalische Chemie, Göttingen, Germany
- Zentrum für Molekulare Biologie der Universität Heidelberg, Heidelberg, Germany
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Azevedo C, Betsuyaku S, Peart J, Takahashi A, Noël L, Sadanandom A, Casais C, Parker J, Shirasu K. Role of SGT1 in resistance protein accumulation in plant immunity. EMBO J 2006; 25:2007-16. [PMID: 16619029 PMCID: PMC1456927 DOI: 10.1038/sj.emboj.7601084] [Citation(s) in RCA: 180] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2005] [Accepted: 03/16/2006] [Indexed: 11/09/2022] Open
Abstract
A highly conserved eukaryotic protein SGT1 binds specifically to the molecular chaperone, HSP90. In plants, SGT1 positively regulates disease resistance conferred by many Resistance (R) proteins and developmental responses to the phytohormone, auxin. We show that silencing of SGT1 in Nicotiana benthamiana causes a reduction in steady-state levels of the R protein, Rx. These data support a role of SGT1 in R protein accumulation, possibly at the level of complex assembly. In Arabidopsis, two SGT1 proteins, AtSGT1a and AtSGT1b, are functionally redundant early in development. AtSGT1a and AtSGT1b are induced in leaves upon infection and either protein can function in resistance once a certain level is attained, depending on the R protein tested. In unchallenged tissues, steady-state AtSGT1b levels are at least four times greater than AtSGT1a. While the respective tetratricopeptide repeat (TPR) domains of SGT1a and SGT1b control protein accumulation, they are dispensable for intrinsic functions of SGT1 in resistance and auxin responses.
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Affiliation(s)
| | - Shigeyuki Betsuyaku
- Max-Planck-Institut für Züchtungsforschung, Department of Plant Microbe Interactions, Köln, Germany
| | - Jack Peart
- The Sainsbury Laboratory, John Innes Centre, Norwich, UK
| | | | - Laurent Noël
- Max-Planck-Institut für Züchtungsforschung, Department of Plant Microbe Interactions, Köln, Germany
- Laboratoire de Biologie du Développement des Plantes, UMR6191 CNRS-CEA, Université Aix-Marseille II, CEN Cadarache, Saint Paul-lez-Durance Cedex, France
| | - Ari Sadanandom
- The Sainsbury Laboratory, John Innes Centre, Norwich, UK
| | | | - Jane Parker
- Max-Planck-Institut für Züchtungsforschung, Department of Plant Microbe Interactions, Köln, Germany
| | - Ken Shirasu
- The Sainsbury Laboratory, John Innes Centre, Norwich, UK
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Yang J, Roe SM, Cliff MJ, Williams MA, Ladbury JE, Cohen PTW, Barford D. Molecular basis for TPR domain-mediated regulation of protein phosphatase 5. EMBO J 2005; 24:1-10. [PMID: 15577939 PMCID: PMC544909 DOI: 10.1038/sj.emboj.7600496] [Citation(s) in RCA: 152] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2004] [Accepted: 11/05/2004] [Indexed: 11/09/2022] Open
Abstract
Protein phosphatase 5 (Ppp5) is a serine/threonine protein phosphatase comprising a regulatory tetratricopeptide repeat (TPR) domain N-terminal to its phosphatase domain. Ppp5 functions in signalling pathways that control cellular responses to stress, glucocorticoids and DNA damage. Its phosphatase activity is suppressed by an autoinhibited conformation maintained by the TPR domain and a C-terminal subdomain. By interacting with the TPR domain, heat shock protein 90 (Hsp90) and fatty acids including arachidonic acid stimulate phosphatase activity. Here, we describe the structure of the autoinhibited state of Ppp5, revealing mechanisms of TPR-mediated phosphatase inhibition and Hsp90- and arachidonic acid-induced stimulation of phosphatase activity. The TPR domain engages with the catalytic channel of the phosphatase domain, restricting access to the catalytic site. This autoinhibited conformation of Ppp5 is stabilised by the C-terminal alphaJ helix that contacts a region of the Hsp90-binding groove on the TPR domain. Hsp90 activates Ppp5 by disrupting TPR-phosphatase domain interactions, permitting substrate access to the constitutively active phosphatase domain, whereas arachidonic acid prompts an alternate conformation of the TPR domain, destabilising the TPR-phosphatase domain interface.
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Affiliation(s)
- Jing Yang
- Section of Structural Biology, The Institute of Cancer Research, Chester Beatty Laboratories, London, UK
| | - S Mark Roe
- Section of Structural Biology, The Institute of Cancer Research, Chester Beatty Laboratories, London, UK
| | - Matthew J Cliff
- Department of Biochemistry and Molecular Biology, University College London, London, UK
| | - Mark A Williams
- Department of Biochemistry and Molecular Biology, University College London, London, UK
| | - John E Ladbury
- Department of Biochemistry and Molecular Biology, University College London, London, UK
| | - Patricia T W Cohen
- MRC Protein Phosphorylation Unit, Division of Cell Signalling, School of Life Sciences, University of Dundee, Dundee, UK
| | - David Barford
- Section of Structural Biology, The Institute of Cancer Research, Chester Beatty Laboratories, London, UK
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Bangs P, Burke B, Powers C, Craig R, Purohit A, Doxsey S. Functional analysis of Tpr: identification of nuclear pore complex association and nuclear localization domains and a role in mRNA export. J Cell Biol 1998; 143:1801-12. [PMID: 9864356 PMCID: PMC2175216 DOI: 10.1083/jcb.143.7.1801] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/1998] [Revised: 11/24/1998] [Indexed: 12/02/2022] Open
Abstract
Tpr is a 270-kD coiled-coil protein localized to intranuclear filaments of the nuclear pore complex (NPC). The mechanism by which Tpr contributes to the structure and function of the nuclear pore is currently unknown. To gain insight into Tpr function, we expressed the full-length protein and several subdomains in mammalian cell lines and examined their effects on nuclear pore function. Through this analysis, we identified an NH2-terminal domain that was sufficient for association with the nucleoplasmic aspect of the NPC. In addition, we unexpectedly found that the acidic COOH terminus was efficiently transported into the nuclear interior, an event that was apparently mediated by a putative nuclear localization sequence. Ectopic expression of the full-length Tpr caused a dramatic accumulation of poly(A)+ RNA within the nucleus. Similar results were observed with domains that localized to the NPC and the nuclear interior. In contrast, expression of these proteins did not appear to affect nuclear import. These data are consistent with a model in which Tpr is tethered to intranuclear filaments of the NPC by its coiled coil domain leaving the acidic COOH terminus free to interact with soluble transport factors and mediate export of macromolecules from the nucleus.
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Affiliation(s)
- P Bangs
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
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