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SET protein accumulation prevents cell death in head and neck squamous cell carcinoma through regulation of redox state and autophagy. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2019; 1866:623-637. [DOI: 10.1016/j.bbamcr.2019.01.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 01/06/2019] [Accepted: 01/08/2019] [Indexed: 12/29/2022]
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Seibert M, Krüger M, Watson NA, Sen O, Daum JR, Slotman JA, Braun T, Houtsmuller AB, Gorbsky GJ, Jacob R, Kracht M, Higgins JMG, Schmitz ML. CDK1-mediated phosphorylation at H2B serine 6 is required for mitotic chromosome segregation. J Cell Biol 2019; 218:1164-1181. [PMID: 30765437 PMCID: PMC6446833 DOI: 10.1083/jcb.201806057] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 10/17/2018] [Accepted: 01/17/2019] [Indexed: 12/11/2022] Open
Abstract
Faithful mitotic chromosome segregation is required for the maintenance of genomic stability. We discovered the phosphorylation of histone H2B at serine 6 (H2B S6ph) as a new chromatin modification site and found that this modification occurs during the early mitotic phases at inner centromeres and pericentromeric heterochromatin. This modification is directly mediated by cyclin B1-associated CDK1, and indirectly by Aurora B, and is antagonized by PP1-mediated dephosphorylation. H2B S6ph impairs chromatin binding of the histone chaperone SET (I2PP2A), which is important for mitotic fidelity. Injection of phosphorylation-specific H2B S6 antibodies in mitotic cells caused anaphase defects with impaired chromosome segregation and incomplete cytokinesis. As H2B S6ph is important for faithful chromosome separation, this modification may contribute to the prevention chromosomal instability and aneuploidy which frequently occur in cancer cells.
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Affiliation(s)
- Markus Seibert
- Institute of Biochemistry, Justus-Liebig-University, Member of the German Center for Lung Research, Giessen, Germany
| | - Marcus Krüger
- Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Cologne, Germany.,Center for Molecular Medicine (CMMC), University of Cologne, Cologne, Germany
| | - Nikolaus A Watson
- Cell Division Biology Research Group, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, England, UK
| | - Onur Sen
- Cell Division Biology Research Group, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, England, UK
| | - John R Daum
- Cell Cycle and Cancer Biology Research Program, Oklahoma Medical Research Foundation, and Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK
| | - Johan A Slotman
- Department of Pathology, Josephine Nefkens Institute, Erasmus Optical Imaging Centre, Erasmus MC, Rotterdam, Netherlands
| | - Thomas Braun
- Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Adriaan B Houtsmuller
- Department of Pathology, Josephine Nefkens Institute, Erasmus Optical Imaging Centre, Erasmus MC, Rotterdam, Netherlands
| | - Gary J Gorbsky
- Cell Cycle and Cancer Biology Research Program, Oklahoma Medical Research Foundation, and Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK
| | - Ralf Jacob
- Department of Cell Biology and Cell Pathology, Philipps University of Marburg, Marburg, Germany
| | - Michael Kracht
- Rudolf-Buchheim-Institute of Pharmacology, Justus-Liebig-University, Member of the German Center for Lung Research, Giessen, Germany
| | - Jonathan M G Higgins
- Cell Division Biology Research Group, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, England, UK
| | - M Lienhard Schmitz
- Institute of Biochemistry, Justus-Liebig-University, Member of the German Center for Lung Research, Giessen, Germany
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Avet C, Denoyelle C, L'Hôte D, Petit F, Guigon CJ, Cohen-Tannoudji J, Simon V. GnRH regulates the expression of its receptor accessory protein SET in pituitary gonadotropes. PLoS One 2018; 13:e0201494. [PMID: 30052687 PMCID: PMC6063425 DOI: 10.1371/journal.pone.0201494] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 07/16/2018] [Indexed: 01/26/2023] Open
Abstract
Reproductive function is under the control of the neurohormone GnRH, which activates a G-protein-coupled receptor (GnRHR) expressed in pituitary gonadotrope cells. GnRHR activates a complex signaling network to regulate synthesis and secretion of the two gonadotropin hormones, luteinizing hormone and follicle-stimulating hormone, both regulating gametogenesis and steroidogenesis in gonads. Recently, in an attempt to identify the mechanisms underlying GnRHR signaling plasticity, we identified the first interacting partner of GnRHR, the proto-oncogene SET. We showed that SET binds to intracellular domains of GnRHR to enhance its coupling to cAMP pathway in αT3-1 gonadotrope cells. Here, we demonstrate that SET protein is rapidly regulated by GnRH, which increases SET phosphorylation state and decreases dose-dependently SET protein level. Our results highlight a post-translational regulation of SET protein involving the proteasome pathway. We determined that SET phosphorylation upon GnRH stimulation is mediated by PKC and that PKC mediates GnRH-induced SET down-regulation. Phosphorylation on serine 9 targets SET for degradation into the proteasome. Furthermore, a non-phosphorylatable SET mutant on serine 9 is resistant to GnRH-induced down-regulation. Altogether, these data suggest that GnRH-induced SET phosphorylation on serine 9 mediates SET protein down-regulation through the proteasome pathway. Noteworthy, SET down-regulation was also observed in response to pulsatile GnRH stimulation in LβT2 gonadotrope cells as well as in vivo in prepubertal female mice supporting its physiological relevance. In conclusion, this study highlights a regulation of SET protein by the neurohormone GnRH and identifies some of the mechanisms involved.
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Affiliation(s)
- Charlotte Avet
- Sorbonne Paris Cité, Université Paris-Diderot, CNRS UMR 8251, INSERM U1133, Biologie Fonctionnelle et Adaptative, Physiologie de l'axe gonadotrope, Paris, France
| | - Chantal Denoyelle
- Sorbonne Paris Cité, Université Paris-Diderot, CNRS UMR 8251, INSERM U1133, Biologie Fonctionnelle et Adaptative, Physiologie de l'axe gonadotrope, Paris, France
| | - David L'Hôte
- Sorbonne Paris Cité, Université Paris-Diderot, CNRS UMR 8251, INSERM U1133, Biologie Fonctionnelle et Adaptative, Physiologie de l'axe gonadotrope, Paris, France
| | - Florence Petit
- Sorbonne Paris Cité, Université Paris-Diderot, CNRS UMR 8251, INSERM U1133, Biologie Fonctionnelle et Adaptative, Physiologie de l'axe gonadotrope, Paris, France
| | - Céline J Guigon
- Sorbonne Paris Cité, Université Paris-Diderot, CNRS UMR 8251, INSERM U1133, Biologie Fonctionnelle et Adaptative, Physiologie de l'axe gonadotrope, Paris, France
| | - Joëlle Cohen-Tannoudji
- Sorbonne Paris Cité, Université Paris-Diderot, CNRS UMR 8251, INSERM U1133, Biologie Fonctionnelle et Adaptative, Physiologie de l'axe gonadotrope, Paris, France
| | - Violaine Simon
- Sorbonne Paris Cité, Université Paris-Diderot, CNRS UMR 8251, INSERM U1133, Biologie Fonctionnelle et Adaptative, Physiologie de l'axe gonadotrope, Paris, France
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The zebrafish homologs of SET/I2PP2A oncoprotein: expression patterns and insights into their physiological roles during development. Biochem J 2016; 473:4609-4627. [PMID: 27754889 DOI: 10.1042/bcj20160523] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 10/13/2016] [Accepted: 10/17/2016] [Indexed: 01/12/2023]
Abstract
The oncoprotein SET/I2PP2A (protein phosphatase 2A inhibitor 2) participates in various cellular mechanisms such as transcription, cell cycle regulation and cell migration. SET is also an inhibitor of the serine/threonine phosphatase PP2A, which is involved in the regulation of cell homeostasis. In zebrafish, there are two paralogous set genes that encode Seta (269 amino acids) and Setb (275 amino acids) proteins which share 94% identity. We show here that seta and setb are similarly expressed in the eye, the otic vesicle, the brain and the lateral line system, as indicated by in situ hybridization labeling. Whole-mount immunofluorescence analysis revealed the expression of Seta/b proteins in the eye retina, the olfactory pit and the lateral line neuromasts. Loss-of-function studies using antisense morpholino oligonucleotides targeting both seta and setb genes (MOab) resulted in increased apoptosis, reduced cell proliferation and morphological defects. The morphant phenotypes were partially rescued when MOab was co-injected with human SET mRNA. Knockdown of setb with a transcription-blocking morpholino oligonucleotide (MOb) resulted in phenotypic defects comparable with those induced by setb gRNA (guide RNA)/Cas9 [CRISPR (clustered regularly interspaced short palindromic repeats)-associated 9] injections. In vivo labeling of hair cells showed a significantly decreased number of neuromasts in MOab-, MOb- and gRNA/Cas9-injected embryos. Microarray analysis of MOab morphant transcriptome revealed differential expression in gene networks controlling transcription in the sensory organs, including the eye retina, the ear and the lateral line. Collectively, our results suggest that seta and setb are required during embryogenesis and play roles in the zebrafish sensory system development.
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In silico synchronization reveals regulators of nuclear ruptures in lamin A/C deficient model cells. Sci Rep 2016; 6:30325. [PMID: 27461848 PMCID: PMC4962089 DOI: 10.1038/srep30325] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 07/04/2016] [Indexed: 11/23/2022] Open
Abstract
The nuclear lamina is a critical regulator of nuclear structure and function. Nuclei from laminopathy patient cells experience repetitive disruptions of the nuclear envelope, causing transient intermingling of nuclear and cytoplasmic components. The exact causes and consequences of these events are not fully understood, but their stochastic occurrence complicates in-depth analyses. To resolve this, we have established a method that enables quantitative investigation of spontaneous nuclear ruptures, based on co-expression of a firmly bound nuclear reference marker and a fluorescent protein that shuttles between the nucleus and cytoplasm during ruptures. Minimally invasive imaging of both reporters, combined with automated tracking and in silico synchronization of individual rupture events, allowed extracting information on rupture frequency and recovery kinetics. Using this approach, we found that rupture frequency correlates inversely with lamin A/C levels, and can be reduced in genome-edited LMNA knockout cells by blocking actomyosin contractility or inhibiting the acetyl-transferase protein NAT10. Nuclear signal recovery followed a kinetic that is co-determined by the severity of the rupture event, and could be prolonged by knockdown of the ESCRT-III complex component CHMP4B. In conclusion, our approach reveals regulators of nuclear rupture induction and repair, which may have critical roles in disease development.
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Fasler-Kan E, Baiken Y, Vorobjev IA, Barteneva NS. Analysis of Nucleocytoplasmic Protein Shuttling by Imaging Flow Cytometry. Methods Mol Biol 2016; 1389:127-137. [PMID: 27460241 DOI: 10.1007/978-1-4939-3302-0_8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Many intracellular signal transduction events involve the reversible shuttling of proteins between the cytoplasm and the nucleus. Study of these processes requires imaging information on the protein localization in a given cell and a large number of measurements to obtain sufficient statistics on the protein localization in the whole population. The protocol describes method for quantitative imaging flow cytometry analysis of intracellular distribution of NF-kappaB in ARPE-19 cells stained with specific fluorochrome-conjugated antibodies. The described technique alone or in combination with standard flow cytometry methods can be applied to study any protein undergoing translocation from cytoplasm into the nucleus in a variety of cell lines as well as in heterogeneous primary cell populations.
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Affiliation(s)
- Elizaveta Fasler-Kan
- Department of Biomedicine, University of Basel and University Hospital Basel, CH-4031, Basel, Switzerland.
- Department of Pediatric Surgery and Department of Clinical Research, Inselspital University Hospital, University of Bern, Bern, CH-3010, Switzerland.
| | - Yeldar Baiken
- Nazarbayev University, Astana, Kazakhstan
- Cellular and Molecular Medicine Program, Boston Children's Hospital, Boston, MA, USA
| | - Ivan A Vorobjev
- Department of Cell Biology and Histology, M.V. Lomonosov Moscow State University, Moscow, 119992, Russia
- A.N. Belozersky Institute of Physico-Chemical Biology, M.V. Lomonosov Moscow State University, Moscow, 119992, Russia
| | - Natasha S Barteneva
- Nazarbayev University, Astana, Kazakhstan
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA
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Zoughlami Y, van Stalborgh AM, van Hennik PB, Hordijk PL. Nucleophosmin1 is a negative regulator of the small GTPase Rac1. PLoS One 2013; 8:e68477. [PMID: 23874639 PMCID: PMC3713031 DOI: 10.1371/journal.pone.0068477] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Accepted: 06/04/2013] [Indexed: 11/19/2022] Open
Abstract
The Rac1 GTPase is a critical regulator of cytoskeletal dynamics and controls many biological processes, such as cell migration, cell-cell contacts, cellular growth and cell division. These complex processes are controlled by Rac1 signaling through effector proteins. We have previously identified several effector proteins of Rac1 that also act as Rac1 regulatory proteins, including caveolin-1 and PACSIN2. Here, we report that Rac1 interacts through its C-terminus with nucleophosmin1 (NPM1), a multifunctional nucleo-cytoplasmic shuttling protein with oncogenic properties. We show that Rac1 controls NPM1 subcellular localization. In cells expressing active Rac1, NPM1 translocates from the nucleus to the cytoplasm. In addition, Rac1 regulates the localization of the phosphorylated pool of NPM1 as this pool translocated from the nucleus to the cytosol in cells expressing activated Rac1. Conversely, we found that expression of NPM1 limits Rac1 GTP loading and cell spreading. In conclusion, this study identifies NPM1 as a novel, negative regulator of Rac1.
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Affiliation(s)
- Younes Zoughlami
- Department of Molecular Cell Biology, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
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Basurto-Islas G, Grundke-Iqbal I, Tung YC, Liu F, Iqbal K. Activation of asparaginyl endopeptidase leads to Tau hyperphosphorylation in Alzheimer disease. J Biol Chem 2013; 288:17495-507. [PMID: 23640887 DOI: 10.1074/jbc.m112.446070] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Neurofibrillary pathology of abnormally hyperphosphorylated Tau is a key lesion of Alzheimer disease and other tauopathies, and its density in the brain directly correlates with dementia. The phosphorylation of Tau is regulated by protein phosphatase 2A, which in turn is regulated by inhibitor 2, I2(PP2A). In acidic conditions such as generated by brain ischemia and hypoxia, especially in association with hyperglycemia as in diabetes, I2(PP2A) is cleaved by asparaginyl endopeptidase at Asn-175 into the N-terminal fragment (I2NTF) and the C-terminal fragment (I2CTF). Both I2NTF and I2CTF are known to bind to the catalytic subunit of protein phosphatase 2A and inhibit its activity. Here we show that the level of activated asparaginyl endopeptidase is significantly increased, and this enzyme and I2(PP2A) translocate, respectively, from neuronal lysosomes and nucleus to the cytoplasm where they interact and are associated with hyperphosphorylated Tau in Alzheimer disease brain. Asparaginyl endopeptidase from Alzheimer disease brain could cleave GST-I2(PP2A), except when I2(PP2A) was mutated at the cleavage site Asn-175 to Gln. Finally, an induction of acidosis by treatment with kainic acid or pH 6.0 medium activated asparaginyl endopeptidase and consequently produced the cleavage of I2(PP2A), inhibition of protein phosphatase 2A, and hyperphosphorylation of Tau, and the knockdown of asparaginyl endopeptidase with siRNA abolished this pathway in SH-SY5Y cells. These findings suggest the involvement of brain acidosis in the etiopathogenesis of Alzheimer disease, and asparaginyl endopeptidase-I2(PP2A)-protein phosphatase 2A-Tau hyperphosphorylation pathway as a therapeutic target.
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Affiliation(s)
- Gustavo Basurto-Islas
- Department of Neurochemistry, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, New York 10314-6399, USA
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