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Niederacher G, Urwin D, Dijkwel Y, Tremethick DJ, Rosengren KJ, Becker CFW, Conibear AC. Site-specific modification and segmental isotope labelling of HMGN1 reveals long-range conformational perturbations caused by posttranslational modifications. RSC Chem Biol 2021; 2:537-550. [PMID: 34458797 PMCID: PMC8341956 DOI: 10.1039/d0cb00175a] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 12/16/2020] [Indexed: 01/03/2023] Open
Abstract
Interactions between histones, which package DNA in eukaryotes, and nuclear proteins such as the high mobility group nucleosome-binding protein HMGN1 are important for regulating access to DNA. HMGN1 is a highly charged and intrinsically disordered protein (IDP) that is modified at several sites by posttranslational modifications (PTMs) - acetylation, phosphorylation and ADP-ribosylation. These PTMs are thought to affect cellular localisation of HMGN1 and its ability to bind nucleosomes; however, little is known about how these PTMs regulate the structure and function of HMGN1 at a molecular level. Here, we combine the chemical biology tools of protein semi-synthesis and site-specific modification to generate a series of unique HMGN1 variants bearing precise PTMs at their N- or C-termini with segmental isotope labelling for NMR spectroscopy. With access to these precisely-defined variants, we show that PTMs in both the N- and C-termini cause changes in the chemical shifts and conformational populations in regions distant from the PTM sites; up to 50-60 residues upstream of the PTM site. The PTMs investigated had only minor effects on binding of HMGN1 to nucleosome core particles, suggesting that they have other regulatory roles. This study demonstrates the power of combining protein semi-synthesis for introduction of site-specific PTMs with segmental isotope labelling for structural biology, allowing us to understand the role of PTMs with atomic precision, from both structural and functional perspectives.
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Affiliation(s)
- Gerhard Niederacher
- Faculty of Chemistry, Institute of Biological Chemistry, University of Vienna Währinger Straße 38 1090 Vienna Austria
| | - Debra Urwin
- John Curtin School of Medical Research, Department of Genome Sciences, The Australian National University ACT 2601 Australia
| | - Yasmin Dijkwel
- John Curtin School of Medical Research, Department of Genome Sciences, The Australian National University ACT 2601 Australia
| | - David J Tremethick
- John Curtin School of Medical Research, Department of Genome Sciences, The Australian National University ACT 2601 Australia
| | - K Johan Rosengren
- School of Biomedical Sciences, The University of Queensland Brisbane QLD 4072 Australia +61-7-3365-1738
| | - Christian F W Becker
- Faculty of Chemistry, Institute of Biological Chemistry, University of Vienna Währinger Straße 38 1090 Vienna Austria
| | - Anne C Conibear
- School of Biomedical Sciences, The University of Queensland Brisbane QLD 4072 Australia +61-7-3365-1738
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2
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Rosales M, Rodríguez-Ulloa A, Besada V, Ramón AC, Pérez GV, Ramos Y, Guirola O, González LJ, Zettl K, Wiśniewski JR, Perera Y, Perea SE. Phosphoproteomic Landscape of AML Cells Treated with the ATP-Competitive CK2 Inhibitor CX-4945. Cells 2021; 10:cells10020338. [PMID: 33562780 PMCID: PMC7915770 DOI: 10.3390/cells10020338] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 01/30/2021] [Accepted: 02/02/2021] [Indexed: 12/13/2022] Open
Abstract
Casein kinase 2 (CK2) regulates a plethora of proteins with pivotal roles in solid and hematological neoplasia. Particularly, in acute myeloid leukemia (AML) CK2 has been pointed as an attractive therapeutic target and prognostic marker. Here, we explored the impact of CK2 inhibition over the phosphoproteome of two cell lines representing major AML subtypes. Quantitative phosphoproteomic analysis was conducted to evaluate changes in phosphorylation levels after incubation with the ATP-competitive CK2 inhibitor CX-4945. Functional enrichment, network analysis, and database mining were performed to identify biological processes, signaling pathways, and CK2 substrates that are responsive to CX-4945. A total of 273 and 1310 phosphopeptides were found differentially modulated in HL-60 and OCI-AML3 cells, respectively. Despite regulated phosphopeptides belong to proteins involved in multiple biological processes and signaling pathways, most of these perturbations can be explain by direct CK2 inhibition rather than off-target effects. Furthermore, CK2 substrates regulated by CX-4945 are mainly related to mRNA processing, translation, DNA repair, and cell cycle. Overall, we evidenced that CK2 inhibitor CX-4945 impinge on mediators of signaling pathways and biological processes essential for primary AML cells survival and chemosensitivity, reinforcing the rationale behind the pharmacologic blockade of protein kinase CK2 for AML targeted therapy.
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Affiliation(s)
- Mauro Rosales
- Department of Animal and Human Biology, Faculty of Biology, University of Havana (UH), Havana 10400, Cuba;
- Molecular Oncology Group, Department of Pharmaceuticals, Biomedical Research Division, Center for Genetic Engineering and Biotechnology (CIGB), Havana 10600, Cuba; (A.C.R.); (G.V.P.)
| | - Arielis Rodríguez-Ulloa
- Mass Spectrometry Laboratory, Proteomics Group, Department of Systems Biology, Biomedical Research Division, CIGB, Havana 10600, Cuba; (A.R.-U.); (V.B.); (Y.R.); (L.J.G.)
| | - Vladimir Besada
- Mass Spectrometry Laboratory, Proteomics Group, Department of Systems Biology, Biomedical Research Division, CIGB, Havana 10600, Cuba; (A.R.-U.); (V.B.); (Y.R.); (L.J.G.)
| | - Ailyn C. Ramón
- Molecular Oncology Group, Department of Pharmaceuticals, Biomedical Research Division, Center for Genetic Engineering and Biotechnology (CIGB), Havana 10600, Cuba; (A.C.R.); (G.V.P.)
| | - George V. Pérez
- Molecular Oncology Group, Department of Pharmaceuticals, Biomedical Research Division, Center for Genetic Engineering and Biotechnology (CIGB), Havana 10600, Cuba; (A.C.R.); (G.V.P.)
| | - Yassel Ramos
- Mass Spectrometry Laboratory, Proteomics Group, Department of Systems Biology, Biomedical Research Division, CIGB, Havana 10600, Cuba; (A.R.-U.); (V.B.); (Y.R.); (L.J.G.)
| | - Osmany Guirola
- Bioinformatics Group, Department of Systems Biology, Biomedical Research Division, CIGB, Havana 10600, Cuba;
| | - Luis J. González
- Mass Spectrometry Laboratory, Proteomics Group, Department of Systems Biology, Biomedical Research Division, CIGB, Havana 10600, Cuba; (A.R.-U.); (V.B.); (Y.R.); (L.J.G.)
| | - Katharina Zettl
- Biochemical Proteomics Group, Department of Proteomics and Signal Transduction, Max-Planck Institute of Biochemistry, 82152 Munich, Germany; (K.Z.); (J.R.W.)
| | - Jacek R. Wiśniewski
- Biochemical Proteomics Group, Department of Proteomics and Signal Transduction, Max-Planck Institute of Biochemistry, 82152 Munich, Germany; (K.Z.); (J.R.W.)
| | - Yasser Perera
- Molecular Oncology Group, Department of Pharmaceuticals, Biomedical Research Division, Center for Genetic Engineering and Biotechnology (CIGB), Havana 10600, Cuba; (A.C.R.); (G.V.P.)
- China-Cuba Biotechnology Joint Innovation Center (CCBJIC), Yongzhou Zhong Gu Biotechnology Co., Ltd, Lengshuitan District, Yongzhou 425000, China
- Correspondence: (Y.P.); (S.E.P.)
| | - Silvio E. Perea
- Molecular Oncology Group, Department of Pharmaceuticals, Biomedical Research Division, Center for Genetic Engineering and Biotechnology (CIGB), Havana 10600, Cuba; (A.C.R.); (G.V.P.)
- Correspondence: (Y.P.); (S.E.P.)
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3
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Medler TR, Craig JM, Fiorillo AA, Feeney YB, Harrell JC, Clevenger CV. HDAC6 Deacetylates HMGN2 to Regulate Stat5a Activity and Breast Cancer Growth. Mol Cancer Res 2016; 14:994-1008. [PMID: 27358110 DOI: 10.1158/1541-7786.mcr-16-0109] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 06/20/2016] [Indexed: 11/16/2022]
Abstract
Stat5a is a transcription factor utilized by several cytokine/hormone receptor signaling pathways that promotes transcription of genes associated with proliferation, differentiation, and survival of cancer cells. However, there are currently no clinically approved therapies that directly target Stat5a, despite ample evidence that it contributes to breast cancer pathogenesis. Here, deacetylation of the Stat5a coactivator and chromatin-remodeling protein HMGN2 on lysine residue K2 by HDAC6 promotes Stat5a-mediated transcription and breast cancer growth. HDAC6 inhibition both in vitro and in vivo enhances HMGN2 acetylation with a concomitant reduction in Stat5a-mediated signaling, resulting in an inhibition of breast cancer growth. Furthermore, HMGN2 is highly acetylated at K2 in normal human breast tissue, but is deacetylated in primary breast tumors and lymph node metastases, suggesting that targeting HMGN2 deacetylation is a viable treatment for breast cancer. Together, these results reveal a novel mechanism by which HDAC6 activity promotes the transcription of Stat5a target genes and demonstrate utility of HDAC6 inhibition for breast cancer therapy. IMPLICATIONS HMGN2 deacetylation enhances Stat5a transcriptional activity, thereby regulating prolactin-induced gene transcription and breast cancer growth. Mol Cancer Res; 14(10); 994-1008. ©2016 AACR.
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Affiliation(s)
- Terry R Medler
- Women's Cancer Research Program, Robert H. Lurie Comprehensive Cancer Center and Department of Pathology, Northwestern University, Chicago, Illinois. Department of Cell, Developmental & Cancer Biology, Oregon Health and Science University, Portland, Oregon
| | - Justin M Craig
- Department of Pathology, Virginia Commonwealth University, Richmond, Virginia
| | - Alyson A Fiorillo
- Women's Cancer Research Program, Robert H. Lurie Comprehensive Cancer Center and Department of Pathology, Northwestern University, Chicago, Illinois
| | - Yvonne B Feeney
- Women's Cancer Research Program, Robert H. Lurie Comprehensive Cancer Center and Department of Pathology, Northwestern University, Chicago, Illinois
| | - J Chuck Harrell
- Department of Pathology, Virginia Commonwealth University, Richmond, Virginia
| | - Charles V Clevenger
- Women's Cancer Research Program, Robert H. Lurie Comprehensive Cancer Center and Department of Pathology, Northwestern University, Chicago, Illinois. Department of Pathology, Virginia Commonwealth University, Richmond, Virginia.
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4
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Nalabothula N, McVicker G, Maiorano J, Martin R, Pritchard JK, Fondufe-Mittendorf YN. The chromatin architectural proteins HMGD1 and H1 bind reciprocally and have opposite effects on chromatin structure and gene regulation. BMC Genomics 2014; 15:92. [PMID: 24484546 PMCID: PMC3928079 DOI: 10.1186/1471-2164-15-92] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Accepted: 01/30/2014] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Chromatin architectural proteins interact with nucleosomes to modulate chromatin accessibility and higher-order chromatin structure. While these proteins are almost certainly important for gene regulation they have been studied far less than the core histone proteins. RESULTS Here we describe the genomic distributions and functional roles of two chromatin architectural proteins: histone H1 and the high mobility group protein HMGD1 in Drosophila S2 cells. Using ChIP-seq, biochemical and gene specific approaches, we find that HMGD1 binds to highly accessible regulatory chromatin and active promoters. In contrast, H1 is primarily associated with heterochromatic regions marked with repressive histone marks. We find that the ratio of HMGD1 to H1 binding is a better predictor of gene activity than either protein by itself, which suggests that reciprocal binding between these proteins is important for gene regulation. Using knockdown experiments, we show that HMGD1 and H1 affect the occupancy of the other protein, change nucleosome repeat length and modulate gene expression. CONCLUSION Collectively, our data suggest that dynamic and mutually exclusive binding of H1 and HMGD1 to nucleosomes and their linker sequences may control the fluid chromatin structure that is required for transcriptional regulation. This study provides a framework to further study the interplay between chromatin architectural proteins and epigenetics in gene regulation.
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5
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Fiorillo AA, Medler TR, Feeney YB, Wetz SM, Tommerdahl KL, Clevenger CV. The prolactin receptor transactivation domain is associated with steroid hormone receptor expression and malignant progression of breast cancer. THE AMERICAN JOURNAL OF PATHOLOGY 2012; 182:217-33. [PMID: 23159947 DOI: 10.1016/j.ajpath.2012.09.021] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2011] [Revised: 08/29/2012] [Accepted: 09/25/2012] [Indexed: 11/27/2022]
Abstract
The polypeptide hormone prolactin (PRL) stimulates breast epithelial cell growth, differentiation, and motility through its cognate receptor, PRLr. PRLr is expressed in most breast cancers; however, its exact role remains elusive. Our laboratory previously described a novel mode of PRLr signaling in which Stat5a-mediated transcription is regulated through ligand-induced phosphorylation of the PRLr transactivation domain (TAD). Herein, we used a PRLr transactivation-deficient mutant (PRLrYDmut) to identify novel TAD-specific target genes. Microarray analysis identified 120 PRL-induced genes up-regulated by wild type but not PRLrYDmut. Compared with control, PRLr expression significantly induced expression of approximately 4700 PRL-induced genes, whereas PRLrYDmut ablated induction of all but 19 of these genes. Ingenuity pathway analysis found that the PRLr TAD most profoundly affected networks involving cancer and proliferation. In support of this, PRLrYDmut expression reduced anchorage-dependent and anchorage-independent growth. In addition, pathway analysis identified a link between the PRLr TAD and the estrogen and progesterone receptors (ERα/PR). Although neither ERα nor PR was identified as a PRL target gene, a TAD mutation significantly impaired ERα/PR expression and estrogen responsiveness. TMA analysis revealed a marked increase in nuclear, but not cytoplasmic, PRLr TAD phosphorylation as a function of neoplastic progression. We propose that PRLr TAD phosphorylation contributes to breast cancer pathogenesis, in part through regulation of ERα and PR, and has potential utility as a biomarker in this disease.
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Affiliation(s)
- Alyson A Fiorillo
- Women's Cancer Research Program, Robert H. Lurie Comprehensive Cancer Center, and the Department of Pathology, Northwestern University, Chicago, Illinois 60611, USA
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6
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Lefèvre PLC, Palin MF, Beaudry D, Dobias-Goff M, Desmarais JA, Llerena V EM, Murphy BD. Uterine signaling at the emergence of the embryo from obligate diapause. Am J Physiol Endocrinol Metab 2011; 300:E800-8. [PMID: 21304066 DOI: 10.1152/ajpendo.00702.2010] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Embryonic diapause is the reversible arrest of embryo development prior to implantation under a regime of uterine control that is not well understood. Our objective was to explore uterine modifications associated with the emergence of embryonic diapause in the mink, a species in which embryonic diapause characterizes every gestation. We investigated the uterine transcriptome at reactivation using the suppressive subtractive hybridization technique. A library of 123 differentially expressed genes between uteri with blastocysts in diapause and reactivated blastocysts was generated. Among those genes, 41.5% encode for potential secreted products that are implicated in regulation of cell proliferation (14%), homeostasis (14%), protein folding (11%), electron transport chain (8%), and innate immune response (8%), therefore suggesting that these biological processes are implicated in blastocyst reactivation. Two genes, the high-mobility group nucleosome binding domain 1 (HMGN1), a chromatin remodeling factor, and the secreted protein acidic and cystein-rich (SPARC), which is implicated in extracellular cell-cell interactions, were submitted to more detailed analysis of expression patterns in the mink uterus at blastocyst reactivation. Expression of both HMGN1 and SPARC was increased significantly in the uterus at embryo reactivation compared with diapause, principally in the endometrial epithelium and subepithelial stroma. These results provide new insight into uterine signaling at the emergence of the blastocyst from diapause and highlight the factors HMGN1 and SPARC as potential inductors of uterine environment modifications underlying uterine signaling during emergence of the embryo from embryonic diapause.
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Affiliation(s)
- Pavine L C Lefèvre
- Centre de Recherche en Reproduction Animale, Faculté de Médecine Vétérinaire, Université de Montréal, 3200 Rue Sicotte, St-Hyacinthe
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7
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Zhang Q, Wang Y. HMG modifications and nuclear function. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2010; 1799:28-36. [PMID: 20123066 DOI: 10.1016/j.bbagrm.2009.11.009] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2009] [Revised: 10/26/2009] [Accepted: 11/03/2009] [Indexed: 12/26/2022]
Abstract
High mobility group (HMG) proteins assume important roles in regulating chromatin dynamics, transcriptional activities of genes and other cellular processes. Post-translational modifications of HMG proteins can alter their interactions with DNA and proteins, and consequently, affect their biological activities. Although the mechanisms through which these modifications are involved in regulating biological processes in different cellular contexts are not fully understood, new insights into these modification "codes" have emerged from the increasing appreciation of the functions of these proteins. In this review, we focus on the chemical modifications of mammalian HMG proteins and highlight their roles in nuclear functions.
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Affiliation(s)
- Qingchun Zhang
- Department of Chemistry, University of California, Riverside, CA 92521-0403, USA
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8
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Zhang Q, Wang Y. High mobility group proteins and their post-translational modifications. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2008; 1784:1159-66. [PMID: 18513496 DOI: 10.1016/j.bbapap.2008.04.028] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2008] [Revised: 04/14/2008] [Accepted: 04/30/2008] [Indexed: 01/10/2023]
Abstract
The high mobility group (HMG) proteins, including HMGA, HMGB and HMGN, are abundant and ubiquitous nuclear proteins that bind to DNA, nucleosome and other multi-protein complexes in a dynamic and reversible fashion to regulate DNA processing in the context of chromatin. All HMG proteins, like histone proteins, are subjected to extensive post-translational modifications (PTMs), such as lysine acetylation, arginine/lysine methylation and serine/threonine phosphorylation, to modulate their interactions with DNA and other proteins. There is a growing appreciation for the complex relationship between the PTMs of HMG proteins and their diverse biological activities. Here, we reviewed the identified covalent modifications of HMG proteins, and highlighted how these PTMs affect the functions of HMG proteins in a variety of cellular processes.
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Affiliation(s)
- Qingchun Zhang
- Department of Chemistry, University of California, Riverside, CA 92521-0403, USA
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9
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Cherukuri S, Hock R, Ueda T, Catez F, Rochman M, Bustin M. Cell cycle-dependent binding of HMGN proteins to chromatin. Mol Biol Cell 2008; 19:1816-24. [PMID: 18287527 DOI: 10.1091/mbc.e07-10-1018] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Throughout the cell cycle, the histones remain associated with DNA, but the repertoire of proteins associated with the chromatin fiber continuously changes. The chromatin interaction of HMGNs, a family of nucleosome binding proteins that modulates the structure and activity of chromatin, during the cell cycle is controversial. Immunofluorescence studies demonstrated that HMGNs are not associated with chromatin, whereas live cell imaging indicated that they are present in mitotic chromosomes. To resolve this controversy, we examined the organization of wild-type and mutated HMGN1 and HMGN2 proteins in the cell nucleus by using immunofluorescence studies, live cell imaging, gel mobility shift assays, and bimolecular fluorescence complementation (BiFC). We find that during interphase, HMGNs bind specifically to nucleosomes and form homodimeric complexes that yield distinct BiFC signals. In metaphase, the nucleosomal binding domain of the protein is inactivated, and the proteins associate with chromatin with low affinity as monomers, and they do not form specific complexes. Our studies demonstrate that the mode of binding of HMGNs to chromatin is cell cycle dependent.
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Affiliation(s)
- Srujana Cherukuri
- Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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10
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Lim JH, Catez F, Birger Y, West KL, Prymakowska-Bosak M, Postnikov YV, Bustin M. Chromosomal protein HMGN1 modulates histone H3 phosphorylation. Mol Cell 2004; 15:573-84. [PMID: 15327773 DOI: 10.1016/j.molcel.2004.08.006] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2003] [Revised: 06/01/2004] [Accepted: 06/10/2004] [Indexed: 11/22/2022]
Abstract
Here we demonstrate that HMGN1, a nuclear protein that binds to nucleosomes and reduces the compaction of the chromatin fiber, modulates histone posttranslational modifications. In Hmgn1-/- cells, loss of HMGN1 elevates the steady-state levels of phospho-S10-H3 and enhances the rate of stress-induced phosphorylation of S10-H3. In vitro, HMGN1 reduces the rate of phospho-S10-H3 by hindering the ability of kinases to modify nucleosomal, but not free, H3. During anisomycin treatment, the phosphorylation of HMGN1 precedes that of H3 and leads to a transient weakening of the binding of HMGN1 to chromatin. We propose that the reduced binding of HMGN1 to nucleosomes, or the absence of the protein, improves access of anisomysin-induced kinases to H3. Thus, the levels of posttranslational modifications in chromatin are modulated by nucleosome binding proteins that alter the ability of enzymatic complexes to access and modify their nucleosomal targets.
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Affiliation(s)
- Jae-Hwan Lim
- Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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11
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The role of HMGN proteins in chromatin function. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/s0167-7306(03)39006-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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12
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Prymakowska-Bosak M, Hock R, Catez F, Lim JH, Birger Y, Shirakawa H, Lee K, Bustin M. Mitotic phosphorylation of chromosomal protein HMGN1 inhibits nuclear import and promotes interaction with 14.3.3 proteins. Mol Cell Biol 2002; 22:6809-19. [PMID: 12215538 PMCID: PMC134047 DOI: 10.1128/mcb.22.19.6809-6819.2002] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Progression through mitosis is associated with reversible phosphorylation of many nuclear proteins including that of the high-mobility group N (HMGN) nucleosomal binding protein family. Here we use immunofluorescence and in vitro nuclear import studies to demonstrate that mitotic phosphorylation of the nucleosomal binding domain (NBD) of the HMGN1 protein prevents its reentry into the newly formed nucleus in late telophase. By microinjecting wild-type and mutant proteins into the cytoplasm of HeLa cells and expressing these proteins in HmgN1(-/-) cells, we demonstrate that the inability to enter the nucleus is a consequence of phosphorylation and is not due to the presence of negative charges. Using affinity chromatography with recombinant proteins and nuclear extracts prepared from logarithmically growing or mitotically arrested cells, we demonstrate that phosphorylation of the NBD of HMGN1 promotes interaction with specific 14.3.3 isotypes. We conclude that mitotic phosphorylation of HMGN1 protein promotes interaction with 14.3.3 proteins and suggest that this interaction impedes the reentry of the proteins into the nucleus during telophase. Taken together with the results of previous studies, our results suggest a dual role for mitotic phosphorylation of HMGN1: abolishment of chromatin binding and inhibition of nuclear import.
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Affiliation(s)
- Marta Prymakowska-Bosak
- Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
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13
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Leong PWF, Liew K, Lim W, Chow VTK. Differential display RT-PCR analysis of enterovirus-71-infected rhabdomyosarcoma cells reveals mRNA expression responses of multiple human genes with known and novel functions. Virology 2002; 295:147-59. [PMID: 12033773 DOI: 10.1006/viro.2002.1353] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In order to better understand cellular responses to viral infection at the transcriptional level, we employed differential display RT-PCR to analyze mRNAs from RD rhabdomyosarcoma cells following infection with a neurovirulent enterovirus 71 (EV71) strain, compared with mRNAs from uninfected cells. Of 250 expressed sequence tags (ESTs) isolated, sequenced, and identified, all were of cellular origin except 1 that was of viral origin. Of these, 156 were individual distinctive clones, comprising 45 mRNAs showing unaltered expression and 111 mRNAs exhibiting upregulation or downregulation. Of the 45 uniformly expressed mRNAs, 14 represented unknown genes. Of the 111 differentially expressed mRNAs, 63 did not match any known genes. Forty-eight of the 111 mRNAs modified by EV71 infection matched known genes, including those encoding components of cell cycle, cytoskeleton, and cell death mediators; protein degradation mediators; mitochondrial-related proteins; components of protein translation and modification; and cellular transport proteins. The altered expression profiles of representative genes were authenticated by semiquantitative RT-PCR and real-time RT-PCR. We also identified a novel alternatively spliced transcript of TRIP7 thyroid receptor interactor protein; the putative human homolog of murine mc7 mRNA predominantly expressed in the brain; and a novel mRNA similar to that encoding vacuolar protein 8 involved in protein targeting. These results underscore the applicability of the mRNA differential display technique for elucidating the expression profiles of known and even novel genes in response to cellular infection with pathogenic viruses.
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Affiliation(s)
- Peter W F Leong
- Human Genome Laboratory, National University of Singapore, Kent Ridge, 117597, Singapore
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14
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Prymakowska-Bosak M, Misteli T, Herrera JE, Shirakawa H, Birger Y, Garfield S, Bustin M. Mitotic phosphorylation prevents the binding of HMGN proteins to chromatin. Mol Cell Biol 2001; 21:5169-78. [PMID: 11438671 PMCID: PMC87241 DOI: 10.1128/mcb.21.15.5169-5178.2001] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Condensation of the chromatin fiber and transcriptional inhibition during mitosis is associated with the redistribution of many DNA- and chromatin-binding proteins, including members of the high-mobility-group N (HMGN) family. Here we study the mechanism governing the organization of HMGN proteins in mitosis. Using site-specific antibodies and quantitative gel analysis with proteins extracted from synchronized HeLa cells, we demonstrate that, during mitosis, the conserved serine residues in the nucleosomal binding domain (NBD) of this protein family are highly and specifically phosphorylated. Nucleosome mobility shift assays with both in vitro-phosphorylated proteins and with point mutants bearing negative charges in the NBD demonstrate that the negative charge abolishes the ability of the proteins to bind to nucleosomes. Fluorescence loss of photobleaching demonstrates that, in living cells, the negative charge in the NBD increases the intranuclear mobility of the protein and significantly decreases the relative time that it is bound to chromatin. Expression of wild-type and mutant proteins in HmgN1(-/-) cells indicates that the negatively charged protein is not bound to chromosomes. We conclude that during mitosis the NBD of HMGN proteins is highly phosphorylated and that this modification regulates the interaction of the proteins with chromatin.
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Affiliation(s)
- M Prymakowska-Bosak
- Protein Section, Laboratory of Metabolism, DBS, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA.
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15
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Schwanbeck R, Gymnopoulos M, Petry I, Piekiełko A, Szewczuk Z, Heyduk T, Zechel K, Wiśniewski JR. Consecutive steps of phosphorylation affect conformation and DNA binding of the chironomus high mobility group A protein. J Biol Chem 2001; 276:26012-21. [PMID: 11335713 DOI: 10.1074/jbc.m011053200] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The high mobility group (HMG) proteins of the AT-hook family (HMGA) lie downstream in regulatory networks with protein kinase C, Cdc2 kinase, MAP kinase, and casein kinase 2 (CK2) as final effectors. In the cells of the midge Chironomus, almost all of the HMGA protein (cHMGA) is phosphorylated by CK2 at two adjacent sites. 40% of the protein population is additionally modified by MAP kinase. Using spectroscopic and protein footprinting techniques, we analyzed how individual and consecutive steps of phosphorylation change the conformation of an HMGA protein and affect its contacts with poly(dA-dT).poly(dA-dT) and a fragment of the interferon-beta promoter. We demonstrate that phosphorylation of cHMGA by CK2 alters its conformation and modulates its DNA binding properties such that a subsequent phosphorylation by Cdc2 kinase changes the organization of the protein-DNA complex. In contrast, consecutive phosphorylation by MAP kinase, which results in a dramatic change in cHMGA conformation, has no direct effect on the complex. Because the phosphorylation of the HMGA proteins attenuates binding affinity and reduces the extent of contacts between the DNA and protein, it is likely that this process mirrors the dynamics and diversity of regulatory processes in chromatin.
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Affiliation(s)
- R Schwanbeck
- III. Zoologisches Institut-Entwicklungsbiologie, Universität Göttingen, Göttingen D 37073, Germany
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Koster S, Duursma MC, Boon JJ, Nielen MW, Heeren RM. Current awareness. JOURNAL OF MASS SPECTROMETRY : JMS 2000; 35:750-759. [PMID: 10862128 DOI: 10.1002/1096-9888(200006)35:6<750::aid-jms979>3.0.co;2-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
In order to keep subscribers up-to-date with the latest developments in their field, John Wiley & Sons are providing a current awareness service in each issue of the journal. The bibliography contains newly published material in the field of mass spectrometry. Each bibliography is divided into 11 sections: 1 Books, Reviews & Symposia; 2 Instrumental Techniques & Methods; 3 Gas Phase Ion Chemistry; 4 Biology/Biochemistry: Amino Acids, Peptides & Proteins; Carbohydrates; Lipids; Nucleic Acids; 5 Pharmacology/Toxicology; 6 Natural Products; 7 Analysis of Organic Compounds; 8 Analysis of Inorganics/Organometallics; 9 Surface Analysis; 10 Environmental Analysis; 11 Elemental Analysis. Within each section, articles are listed in alphabetical order with respect to author (5 Weeks journals - Search completed at 22nd. Mar 2000)
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Affiliation(s)
- S Koster
- Unit for Macromolecular Mass Spectrometry, FOM-Institute for Atomic and Molecular Physics, Kruislaan 407, 1098 SJ Amsterdam, The Netherlands
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