1
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Heller S, Glaeske S, Gluske K, Paul J, Böhme A, Janzer A, Roider HG, Montebaur A, Nicke B, Lesche R, von Ahsen O, Politz O, Liu N, Gorjánácz M. Pan-PI3K inhibition with copanlisib overcomes Treg- and M2-TAM-mediated immune suppression and promotes anti-tumor immune responses. Clin Exp Med 2023; 23:5445-5461. [PMID: 37935952 PMCID: PMC10725385 DOI: 10.1007/s10238-023-01227-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Accepted: 10/17/2023] [Indexed: 11/09/2023]
Abstract
The PI3K pathway is one of the most frequently altered signaling pathways in human cancer. In addition to its function in cancer cells, PI3K plays a complex role in modulating anti-tumor immune responses upon immune checkpoint inhibition (ICI). Here, we evaluated the effects of the pan-Class I PI3K inhibitor copanlisib on different immune cell types in vitro and on tumor growth and immune cell infiltration in syngeneic murine cancer models. Intermittent treatment with copanlisib resulted in a strong in vivo anti-tumor efficacy, increased tumor infiltration of activated T cells and macrophages, and increased CD8+ T cell/regulatory T cell and M1/M2 macrophage ratios. The strong in vivo efficacy was at least partially due to immunomodulatory activity of copanlisib, as in vitro these murine cancer cells were resistant to PI3K inhibition. Furthermore, the combination of copanlisib with the ICI antibody anti-PD-1 demonstrated enhanced anti-tumor efficacy in both ICI-sensitive and insensitive syngeneic mouse tumor models. Importantly, in an ICI-sensitive model, combination therapy resulted in complete remission and prevention of tumor recurrence. Thus, the combination of ICIs with PI3K inhibition by intermittently dosed copanlisib represents a promising new strategy to increase sensitivity to ICI therapies and to treat human solid cancers.
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Affiliation(s)
| | - Sarah Glaeske
- Bayer AG, Pharmaceuticals, Research & Early Development Oncology, Berlin, Germany
| | - Katja Gluske
- Bayer AG, Pharmaceuticals, Research & Early Development Oncology, Berlin, Germany
| | - Juliane Paul
- Bayer AG, Pharmaceuticals, Research & Early Development Oncology, Berlin, Germany
| | | | - Andreas Janzer
- Bayer AG, Pharmaceuticals, Research & Early Development Oncology, Berlin, Germany
| | | | - Anna Montebaur
- Bayer AG, Pharmaceuticals, Research & Early Development Oncology, Berlin, Germany
| | | | | | | | - Oliver Politz
- Bayer AG, Pharmaceuticals, Research & Early Development Oncology, Berlin, Germany
| | - Ningshu Liu
- Bayer AG, Pharmaceuticals, Research & Early Development Oncology, Berlin, Germany
- Fosun Pharma, No. 1289 Yishan Road, Shanghai City, China
| | - Mátyás Gorjánácz
- Bayer AG, Pharmaceuticals, Research & Early Development Oncology, Berlin, Germany.
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2
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Kober C, Roewe J, Schmees N, Roese L, Roehn U, Bader B, Stoeckigt D, Prinz F, Gorjánácz M, Roider HG, Olesch C, Leder G, Irlbacher H, Lesche R, Lefranc J, Oezcan-Wahlbrink M, Batra AS, Elmadany N, Carretero R, Sahm K, Oezen I, Cichon F, Baumann D, Sadik A, Opitz CA, Weinmann H, Hartung IV, Kreft B, Offringa R, Platten M, Gutcher I. Targeting the aryl hydrocarbon receptor (AhR) with BAY 2416964: a selective small molecule inhibitor for cancer immunotherapy. J Immunother Cancer 2023; 11:e007495. [PMID: 37963637 PMCID: PMC10649913 DOI: 10.1136/jitc-2023-007495] [Citation(s) in RCA: 0] [Impact Index Per Article: 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] [Accepted: 10/08/2023] [Indexed: 11/16/2023] Open
Abstract
BACKGROUND The metabolism of tryptophan to kynurenines (KYN) by indoleamine-2,3-dioxygenase or tryptophan-2,3-dioxygenase is a key pathway of constitutive and adaptive tumor immune resistance. The immunosuppressive effects of KYN in the tumor microenvironment are predominantly mediated by the aryl hydrocarbon receptor (AhR), a cytosolic transcription factor that broadly suppresses immune cell function. Inhibition of AhR thus offers an antitumor therapy opportunity via restoration of immune system functions. METHODS The expression of AhR was evaluated in tissue microarrays of head and neck squamous cell carcinoma (HNSCC), non-small cell lung cancer (NSCLC) and colorectal cancer (CRC). A structure class of inhibitors that block AhR activation by exogenous and endogenous ligands was identified, and further optimized, using a cellular screening cascade. The antagonistic properties of the selected AhR inhibitor candidate BAY 2416964 were determined using transactivation assays. Nuclear translocation, target engagement and the effect of BAY 2416964 on agonist-induced AhR activation were assessed in human and mouse cancer cells. The immunostimulatory properties on gene and cytokine expression were examined in human immune cell subsets. The in vivo efficacy of BAY 2416964 was tested in the syngeneic ovalbumin-expressing B16F10 melanoma model in mice. Coculture of human H1299 NSCLC cells, primary peripheral blood mononuclear cells and fibroblasts mimicking the human stromal-tumor microenvironment was used to assess the effects of AhR inhibition on human immune cells. Furthermore, tumor spheroids cocultured with tumor antigen-specific MART-1 T cells were used to study the antigen-specific cytotoxic T cell responses. The data were analyzed statistically using linear models. RESULTS AhR expression was observed in tumor cells and tumor-infiltrating immune cells in HNSCC, NSCLC and CRC. BAY 2416964 potently and selectively inhibited AhR activation induced by either exogenous or endogenous AhR ligands. In vitro, BAY 2416964 restored immune cell function in human and mouse cells, and furthermore enhanced antigen-specific cytotoxic T cell responses and killing of tumor spheroids. In vivo, oral application with BAY 2416964 was well tolerated, induced a proinflammatory tumor microenvironment, and demonstrated antitumor efficacy in a syngeneic cancer model in mice. CONCLUSIONS These findings identify AhR inhibition as a novel therapeutic approach to overcome immune resistance in various types of cancers.
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Affiliation(s)
- Christina Kober
- Bayer AG, Pharmaceutical Division, Berlin, Germany
- DKFZ-Bayer Joint Immunotherapy Laboratory (D220), DKFZ-Bayer Joint Immunotherapy Laboratory, Heidelberg, Germany
| | - Julian Roewe
- German Cancer Consortium (DKTK), Clinical Cooperation Unit (CCU), Neuroimmunology and Brain Tumor Immunology, German Cancer Research Center, Heidelberg, Germany
- Department of Neurology, Medical Faculty Mannheim, MCTN, Heidelberg University, Heidelberg, Germany
| | | | - Lars Roese
- Bayer AG, Pharmaceutical Division, Berlin, Germany
| | - Ulrike Roehn
- Bayer AG, Pharmaceutical Division, Berlin, Germany
| | | | | | | | | | | | - Catherine Olesch
- Bayer AG, Pharmaceutical Division, Berlin, Germany
- DKFZ-Bayer Joint Immunotherapy Laboratory (D220), DKFZ-Bayer Joint Immunotherapy Laboratory, Heidelberg, Germany
| | | | | | - Ralf Lesche
- Bayer AG, Pharmaceutical Division, Berlin, Germany
| | | | - Mine Oezcan-Wahlbrink
- Bayer AG, Pharmaceutical Division, Berlin, Germany
- DKFZ-Bayer Joint Immunotherapy Laboratory (D220), DKFZ-Bayer Joint Immunotherapy Laboratory, Heidelberg, Germany
| | - Ankita Sati Batra
- German Cancer Consortium (DKTK), Clinical Cooperation Unit (CCU), Neuroimmunology and Brain Tumor Immunology, German Cancer Research Center, Heidelberg, Germany
- Department of Neurology, Medical Faculty Mannheim, MCTN, Heidelberg University, Heidelberg, Germany
| | - Nirmeen Elmadany
- German Cancer Consortium (DKTK), Clinical Cooperation Unit (CCU), Neuroimmunology and Brain Tumor Immunology, German Cancer Research Center, Heidelberg, Germany
- Department of Neurology, Medical Faculty Mannheim, MCTN, Heidelberg University, Heidelberg, Germany
| | - Rafael Carretero
- Bayer AG, Pharmaceutical Division, Berlin, Germany
- DKFZ-Bayer Joint Immunotherapy Laboratory (D220), DKFZ-Bayer Joint Immunotherapy Laboratory, Heidelberg, Germany
| | - Katharina Sahm
- German Cancer Consortium (DKTK), Clinical Cooperation Unit (CCU), Neuroimmunology and Brain Tumor Immunology, German Cancer Research Center, Heidelberg, Germany
- Department of Neurology, Medical Faculty Mannheim, MCTN, Heidelberg University, Heidelberg, Germany
| | - Iris Oezen
- German Cancer Consortium (DKTK), Clinical Cooperation Unit (CCU), Neuroimmunology and Brain Tumor Immunology, German Cancer Research Center, Heidelberg, Germany
| | - Frederik Cichon
- German Cancer Consortium (DKTK), Clinical Cooperation Unit (CCU), Neuroimmunology and Brain Tumor Immunology, German Cancer Research Center, Heidelberg, Germany
| | - Daniel Baumann
- DKFZ-Bayer Joint Immunotherapy Laboratory (D220), DKFZ-Bayer Joint Immunotherapy Laboratory, Heidelberg, Germany
| | - Ahmed Sadik
- Brain Cancer Metabolism (B350), German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Christiane A Opitz
- Brain Cancer Metabolism (B350), German Cancer Research Center (DKFZ), Heidelberg, Germany
| | | | | | | | - Rienk Offringa
- DKFZ-Bayer Joint Immunotherapy Laboratory (D220), DKFZ-Bayer Joint Immunotherapy Laboratory, Heidelberg, Germany
- Department of Surgery, University Hospital Heidelberg, Heidelberg, Germany
| | - Michael Platten
- German Cancer Consortium (DKTK), Clinical Cooperation Unit (CCU), Neuroimmunology and Brain Tumor Immunology, German Cancer Research Center, Heidelberg, Germany
- Department of Neurology, Medical Faculty Mannheim, MCTN, Heidelberg University, Heidelberg, Germany
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3
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Evans CM, Phillips M, Malone KL, Tonelli M, Cornilescu G, Cornilescu C, Holton SJ, Gorjánácz M, Wang L, Carlson S, Gay JC, Nix JC, Demeler B, Markley JL, Glass KC. Coordination of Di-Acetylated Histone Ligands by the ATAD2 Bromodomain. Int J Mol Sci 2021; 22:9128. [PMID: 34502039 PMCID: PMC8430952 DOI: 10.3390/ijms22179128] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [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: 07/26/2021] [Revised: 08/13/2021] [Accepted: 08/17/2021] [Indexed: 12/15/2022] Open
Abstract
The ATPase Family, AAA domain-containing protein 2 (ATAD2) bromodomain (BRD) has a canonical bromodomain structure consisting of four α-helices. ATAD2 functions as a co-activator of the androgen and estrogen receptors as well as the MYC and E2F transcription factors. ATAD2 also functions during DNA replication, recognizing newly synthesized histones. In addition, ATAD2 is shown to be up-regulated in multiple forms of cancer including breast, lung, gastric, endometrial, renal, and prostate. Furthermore, up-regulation of ATAD2 is strongly correlated with poor prognosis in many types of cancer, making the ATAD2 bromodomain an innovative target for cancer therapeutics. In this study, we describe the recognition of histone acetyllysine modifications by the ATAD2 bromodomain. Residue-specific information on the complex formed between the histone tail and the ATAD2 bromodomain, obtained through nuclear magnetic resonance spectroscopy (NMR) and X-ray crystallography, illustrates key residues lining the binding pocket, which are involved in coordination of di-acetylated histone tails. Analytical ultracentrifugation, NMR relaxation data, and isothermal titration calorimetry further confirm the monomeric state of the functionally active ATAD2 bromodomain in complex with di-acetylated histone ligands. Overall, we describe histone tail recognition by ATAD2 BRD and illustrate that one acetyllysine group is primarily engaged by the conserved asparagine (N1064), the "RVF" shelf residues, and the flexible ZA loop. Coordination of a second acetyllysine group also occurs within the same binding pocket but is essentially governed by unique hydrophobic and electrostatic interactions making the di-acetyllysine histone coordination more specific than previously presumed.
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Affiliation(s)
- Chiara M. Evans
- Department of Pharmaceutical Sciences, Albany College of Pharmacy and Health Sciences, Colchester, VT 05446, USA; (C.M.E.); (M.P.); (K.L.M.); (S.C.); (J.C.G.)
| | - Margaret Phillips
- Department of Pharmaceutical Sciences, Albany College of Pharmacy and Health Sciences, Colchester, VT 05446, USA; (C.M.E.); (M.P.); (K.L.M.); (S.C.); (J.C.G.)
- Department of Pharmacology, Larner College of Medicine, University of Vermont, Burlington, VT 05405, USA
| | - Kiera L. Malone
- Department of Pharmaceutical Sciences, Albany College of Pharmacy and Health Sciences, Colchester, VT 05446, USA; (C.M.E.); (M.P.); (K.L.M.); (S.C.); (J.C.G.)
- Department of Pharmacology, Larner College of Medicine, University of Vermont, Burlington, VT 05405, USA
| | - Marco Tonelli
- National Magnetic Resonance Facility at Madison, University of Wisconsin-Madison, Madison, WI 53706, USA; (M.T.); (G.C.); (C.C.); (J.L.M.)
| | - Gabriel Cornilescu
- National Magnetic Resonance Facility at Madison, University of Wisconsin-Madison, Madison, WI 53706, USA; (M.T.); (G.C.); (C.C.); (J.L.M.)
| | - Claudia Cornilescu
- National Magnetic Resonance Facility at Madison, University of Wisconsin-Madison, Madison, WI 53706, USA; (M.T.); (G.C.); (C.C.); (J.L.M.)
| | - Simon J. Holton
- Bayer AG, Pharmaceuticals, Research & Early Development Oncology, 13353 Berlin, Germany; (S.J.H.); (M.G.)
| | - Mátyás Gorjánácz
- Bayer AG, Pharmaceuticals, Research & Early Development Oncology, 13353 Berlin, Germany; (S.J.H.); (M.G.)
| | - Liping Wang
- Department of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, TX 78229, USA; (L.W.); (B.D.)
| | - Samuel Carlson
- Department of Pharmaceutical Sciences, Albany College of Pharmacy and Health Sciences, Colchester, VT 05446, USA; (C.M.E.); (M.P.); (K.L.M.); (S.C.); (J.C.G.)
| | - Jamie C. Gay
- Department of Pharmaceutical Sciences, Albany College of Pharmacy and Health Sciences, Colchester, VT 05446, USA; (C.M.E.); (M.P.); (K.L.M.); (S.C.); (J.C.G.)
| | - Jay C. Nix
- Molecular Biology Consortium, Advanced Light Source, Berkeley, CA 94720, USA;
| | - Borries Demeler
- Department of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, TX 78229, USA; (L.W.); (B.D.)
- Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada
| | - John L. Markley
- National Magnetic Resonance Facility at Madison, University of Wisconsin-Madison, Madison, WI 53706, USA; (M.T.); (G.C.); (C.C.); (J.L.M.)
| | - Karen C. Glass
- Department of Pharmaceutical Sciences, Albany College of Pharmacy and Health Sciences, Colchester, VT 05446, USA; (C.M.E.); (M.P.); (K.L.M.); (S.C.); (J.C.G.)
- Department of Pharmacology, Larner College of Medicine, University of Vermont, Burlington, VT 05405, USA
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4
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Rahm F, Viklund J, Trésaugues L, Ellermann M, Giese A, Ericsson U, Forsblom R, Ginman T, Günther J, Hallberg K, Lindström J, Persson LB, Silvander C, Talagas A, Díaz-Sáez L, Fedorov O, Huber KVM, Panagakou I, Siejka P, Gorjánácz M, Bauser M, Andersson M. Creation of a Novel Class of Potent and Selective MutT Homologue 1 (MTH1) Inhibitors Using Fragment-Based Screening and Structure-Based Drug Design. J Med Chem 2018; 61:2533-2551. [DOI: 10.1021/acs.jmedchem.7b01884] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Fredrik Rahm
- Sprint Bioscience AB, Novum, 14157 Huddinge, Sweden
| | | | | | | | - Anja Giese
- Bayer AG, Muellerstrasse 178, 13353 Berlin, Germany
| | | | | | | | | | | | | | | | | | | | - Laura Díaz-Sáez
- Structural Genomics Consortium, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7DQ, United Kingdom
- Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7FZ, United Kingdom
| | - Oleg Fedorov
- Structural Genomics Consortium, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7DQ, United Kingdom
- Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7FZ, United Kingdom
| | - Kilian V. M. Huber
- Structural Genomics Consortium, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7DQ, United Kingdom
- Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7FZ, United Kingdom
| | - Ioanna Panagakou
- Structural Genomics Consortium, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7DQ, United Kingdom
- Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7FZ, United Kingdom
| | - Paulina Siejka
- Structural Genomics Consortium, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7DQ, United Kingdom
- Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7FZ, United Kingdom
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5
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Koo SJ, Fernández-Montalván AE, Badock V, Ott CJ, Holton SJ, von Ahsen O, Toedling J, Vittori S, Bradner JE, Gorjánácz M. ATAD2 is an epigenetic reader of newly synthesized histone marks during DNA replication. Oncotarget 2018; 7:70323-70335. [PMID: 27612420 PMCID: PMC5342555 DOI: 10.18632/oncotarget.11855] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 08/21/2016] [Indexed: 02/02/2023] Open
Abstract
ATAD2 (ATPase family AAA domain-containing protein 2) is a chromatin regulator harboring an AAA+ ATPase domain and a bromodomain, previously proposed to function as an oncogenic transcription co-factor. Here we suggest that ATAD2 is also required for DNA replication. ATAD2 is co-expressed with genes involved in DNA replication in various cancer types and predominantly expressed in S phase cells where it localized on nascent chromatin (replication sites). Our extensive biochemical and cellular analyses revealed that ATAD2 is recruited to replication sites through a direct interaction with di-acetylated histone H4 at K5 and K12, indicative of newly synthesized histones during replication-coupled chromatin reassembly. Similar to ATAD2-depletion, ectopic expression of ATAD2 mutants that are deficient in binding to these di-acetylation marks resulted in reduced DNA replication and impaired loading of PCNA onto chromatin, suggesting relevance of ATAD2 in DNA replication. Taken together, our data show a novel function of ATAD2 in cancer and for the first time identify a reader of newly synthesized histone di-acetylation-marks during replication.
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Affiliation(s)
| | | | | | - Christopher J Ott
- Center for the Science of Therapeutics, Broad Institute, Cambridge, MA, USA.,Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA.,Department of Medicine, Harvard Medical School, Boston, MA, USA
| | | | | | | | - Sarah Vittori
- Center for the Science of Therapeutics, Broad Institute, Cambridge, MA, USA.,Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - James E Bradner
- Center for the Science of Therapeutics, Broad Institute, Cambridge, MA, USA.,Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA.,Department of Medicine, Harvard Medical School, Boston, MA, USA.,Present address: Novartis Institute for BioMedical Research, Cambridge, MA, USA
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6
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Santarella-Mellwig R, Franke J, Jaedicke A, Gorjánácz M, Bauer U, Budd A, Mattaj IW, Devos DP. Correction: The Compartmentalized Bacteria of the Planctomycetes-Verrucomicrobia-Chlamydiae Superphylum Have Membrane Coat-Like Proteins. PLoS Biol 2018; 16:e1002620. [PMID: 29444088 PMCID: PMC5812719 DOI: 10.1371/journal.pbio.1002620] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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7
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Fernández-Montalván AE, Berger M, Kuropka B, Koo SJ, Badock V, Weiske J, Puetter V, Holton SJ, Stöckigt D, ter Laak A, Centrella PA, Clark MA, Dumelin CE, Sigel EA, Soutter HH, Troast DM, Zhang Y, Cuozzo JW, Keefe AD, Roche D, Rodeschini V, Chaikuad A, Díaz-Sáez L, Bennett JM, Fedorov O, Huber KVM, Hübner J, Weinmann H, Hartung IV, Gorjánácz M. Isoform-Selective ATAD2 Chemical Probe with Novel Chemical Structure and Unusual Mode of Action. ACS Chem Biol 2017; 12:2730-2736. [PMID: 29043777 PMCID: PMC6218015 DOI: 10.1021/acschembio.7b00708] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
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ATAD2
(ANCCA) is an epigenetic regulator and transcriptional cofactor,
whose overexpression has been linked to the progress of various cancer
types. Here, we report a DNA-encoded library screen leading to the
discovery of BAY-850, a potent and isoform selective inhibitor that
specifically induces ATAD2 bromodomain dimerization and prevents interactions
with acetylated histones in vitro, as well as with
chromatin in cells. These features qualify BAY-850 as a chemical probe
to explore ATAD2 biology.
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Affiliation(s)
| | - Markus Berger
- Bayer AG, Pharmaceuticals, Drug Discovery, Berlin, Germany
| | - Benno Kuropka
- Bayer AG, Pharmaceuticals, Drug Discovery, Berlin, Germany
| | - Seong Joo Koo
- Bayer AG, Pharmaceuticals, Drug Discovery, Berlin, Germany
| | - Volker Badock
- Bayer AG, Pharmaceuticals, Drug Discovery, Berlin, Germany
| | - Joerg Weiske
- Bayer AG, Pharmaceuticals, Drug Discovery, Berlin, Germany
| | - Vera Puetter
- Bayer AG, Pharmaceuticals, Drug Discovery, Berlin, Germany
| | | | | | | | | | | | | | - Eric A. Sigel
- X-Chem Pharmaceuticals, Waltham, Massachusetts United States
| | | | - Dawn M. Troast
- X-Chem Pharmaceuticals, Waltham, Massachusetts United States
| | - Ying Zhang
- X-Chem Pharmaceuticals, Waltham, Massachusetts United States
| | - John W. Cuozzo
- X-Chem Pharmaceuticals, Waltham, Massachusetts United States
| | | | | | | | - Apirat Chaikuad
- Structural Genomics Consortium, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Laura Díaz-Sáez
- Structural Genomics Consortium, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - James M. Bennett
- Structural Genomics Consortium, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Oleg Fedorov
- Structural Genomics Consortium, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Kilian V. M. Huber
- Structural Genomics Consortium, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Jan Hübner
- Bayer AG, Pharmaceuticals, Drug Discovery, Berlin, Germany
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8
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Ellermann M, Eheim A, Rahm F, Viklund J, Guenther J, Andersson M, Ericsson U, Forsblom R, Ginman T, Lindström J, Silvander C, Trésaugues L, Giese A, Bunse S, Neuhaus R, Weiske J, Quanz M, Glasauer A, Nowak-Reppel K, Bader B, Irlbacher H, Meyer H, Queisser N, Bauser M, Haegebarth A, Gorjánácz M. Novel Class of Potent and Cellularly Active Inhibitors Devalidates MTH1 as Broad-Spectrum Cancer Target. ACS Chem Biol 2017; 12:1986-1992. [PMID: 28679043 DOI: 10.1021/acschembio.7b00370] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
MTH1 is a hydrolase responsible for sanitization of oxidized purine nucleoside triphosphates to prevent their incorporation into replicating DNA. Early tool compounds published in the literature inhibited the enzymatic activity of MTH1 and subsequently induced cancer cell death; however recent studies have questioned the reported link between these two events. Therefore, it is important to validate MTH1 as a cancer dependency with high quality chemical probes. Here, we present BAY-707, a substrate-competitive, highly potent and selective inhibitor of MTH1, chemically distinct compared to those previously published. Despite superior cellular target engagement and pharmacokinetic properties, inhibition of MTH1 with BAY-707 resulted in a clear lack of in vitro or in vivo anticancer efficacy either in mono- or in combination therapies. Therefore, we conclude that MTH1 is dispensable for cancer cell survival.
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9
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Bone CR, Tapley EC, Gorjánácz M, Starr DA. The Caenorhabditis elegans SUN protein UNC-84 interacts with lamin to transfer forces from the cytoplasm to the nucleoskeleton during nuclear migration. Mol Biol Cell 2014; 25:2853-65. [PMID: 25057012 PMCID: PMC4161519 DOI: 10.1091/mbc.e14-05-0971] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The nucleoplasmic domain of the Caenorhabditis elegans SUN protein UNC-84 interacts with lamin. If this interaction is disrupted, a partial failure in nuclear migration occurs. Nuclear migration is a critical component of many cellular and developmental processes. The nuclear envelope forms a barrier between the cytoplasm, where mechanical forces are generated, and the nucleoskeleton. The LINC complex consists of KASH proteins in the outer nuclear membrane and SUN proteins in the inner nuclear membrane that bridge the nuclear envelope. How forces are transferred from the LINC complex to the nucleoskeleton is poorly understood. The Caenorhabditis elegans lamin, LMN-1, is required for nuclear migration and interacts with the nucleoplasmic domain of the SUN protein UNC-84. This interaction is weakened by the unc-84(P91S) missense mutation. These mutant nuclei have an intermediate nuclear migration defect—live imaging of nuclei or LMN-1::GFP shows that many nuclei migrate normally, others initiate migration before subsequently failing, and others fail to begin migration. At least one other component of the nucleoskeleton, the NET5/Samp1/Ima1 homologue SAMP-1, plays a role in nuclear migration. We propose a nut-and-bolt model to explain how forces are dissipated across the nuclear envelope during nuclear migration. In this model, SUN/KASH bridges serve as bolts through the nuclear envelope, and nucleoskeleton components LMN-1 and SAMP-1 act as both nuts and washers on the inside of the nucleus.
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Affiliation(s)
- Courtney R Bone
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95618
| | - Erin C Tapley
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95618
| | - Mátyás Gorjánácz
- European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Daniel A Starr
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95618
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10
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Abstract
Current anti-cancer therapies have a great deal of undesirable side effects; therefore, there is a need to develop efficient and cancer cell-specific new drugs without strong dose-limiting side effects. In my opinion, mechanisms of nuclear assembly and organization represent a novel platform for drug targets, which might fulfill these criteria. The nuclear stiffness and organization of some cancer types are often compromised, making them more vulnerable for further targeting the mechanisms of nuclear integrity than their normal counterparts. Here I will discuss the nuclear organization of normal cells and cancer cells, the molecular mechanisms that govern nuclear assembly with emphasis on those that, in my view, might be considered as targets for future anti-cancer therapies.
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Affiliation(s)
- Mátyás Gorjánácz
- Bayer Pharma AG; Bayer Healthcare Pharmaceuticals; Global Drug Discovery; Therapeutic Research Group Oncology; Berlin, Germany
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11
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Abstract
The transitions between the successive cell cycle stages depend on reversible protein phosphorylation events. The phosphorylation state of every protein within a cell is strictly determined by spatiotemporally controlled kinase and phosphatase activities. Nuclear disassembly and reassembly during open mitosis in higher eukaryotic cells is one such process that is tightly regulated by the reversible phosphorylation of key proteins. However, little is known about the regulation of these mitotic events. In particular, although kinase function during entry into mitosis is better studied, very little is known about how proteins are dephosphorylated to allow nuclear reformation at the end of mitosis. We have identified LEM‑4, a conserved protein of the nuclear envelope, as an essential coordinator of kinase and phosphatase activities during mitotic exit. Inhibition of VRK‑1 kinase and promotion of a PP2A phosphatase complex by LEM‑4 tightly regulate the phosphorylation state of BAF, an essential player of nuclear reformation at the end of mitosis. Here I offer extended comments on the contribution of LEM‑4 in the regulation of protein phosphorylation and nuclear reformation.
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12
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Mall M, Walter T, Gorjánácz M, Davidson IF, Nga Ly-Hartig TB, Ellenberg J, Mattaj IW. Mitotic lamin disassembly is triggered by lipid-mediated signaling. J Cell Biol 2012; 198:981-90. [PMID: 22986494 PMCID: PMC3444782 DOI: 10.1083/jcb.201205103] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Accepted: 08/20/2012] [Indexed: 11/22/2022] Open
Abstract
Disassembly of the nuclear lamina is a key step during open mitosis in higher eukaryotes. The activity of several kinases, including CDK1 (cyclin-dependent kinase 1) and protein kinase C (PKC), has been shown to trigger mitotic lamin disassembly, yet their precise contributions are unclear. In this study, we develop a quantitative imaging assay to study mitotic lamin B1 disassembly in living cells. We find that CDK1 and PKC act in concert to mediate phosphorylation-dependent lamin B1 disassembly during mitosis. Using ribonucleic acid interference (RNAi), we showed that diacylglycerol (DAG)-dependent PKCs triggered rate-limiting steps of lamin disassembly. RNAi-mediated depletion or chemical inhibition of lipins, enzymes that produce DAG, delayed lamin disassembly to a similar extent as does PKC inhibition/depletion. Furthermore, the delay of lamin B1 disassembly after lipin depletion could be rescued by the addition of DAG. These findings suggest that lipins activate a PKC-dependent pathway during mitotic lamin disassembly and provide evidence for a lipid-mediated mitotic signaling event.
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Affiliation(s)
- Moritz Mall
- European Molecular Biology Laboratory, 69117 Heidelberg, Germany
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13
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Asencio C, Davidson I, Santarella-Mellwig R, Ly-Hartig T, Mall M, Wallenfang M, Mattaj I, Gorjánácz M. Coordination of Kinase and Phosphatase Activities by Lem4 Enables Nuclear Envelope Reassembly during Mitosis. Cell 2012; 150:122-35. [DOI: 10.1016/j.cell.2012.04.043] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2011] [Revised: 02/09/2012] [Accepted: 04/20/2012] [Indexed: 12/19/2022]
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14
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Joseph-Strauss D, Gorjánácz M, Santarella-Mellwig R, Voronina E, Audhya A, Cohen-Fix O. Sm protein down-regulation leads to defects in nuclear pore complex disassembly and distribution in C. elegans embryos. Dev Biol 2012; 365:445-57. [PMID: 22426005 DOI: 10.1016/j.ydbio.2012.02.036] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Revised: 01/24/2012] [Accepted: 02/29/2012] [Indexed: 10/28/2022]
Abstract
Nuclear pore complexes (NPCs) are large macromolecular structures embedded in the nuclear envelope (NE), where they facilitate exchange of molecules between the cytoplasm and the nucleoplasm. In most cell types, NPCs are evenly distributed around the NE. However, the mechanisms dictating NPC distribution are largely unknown. Here, we used the model organism Caenorhabditis elegans to identify genes that affect NPC distribution during early embryonic divisions. We found that down-regulation of the Sm proteins, which are core components of the spliceosome, but not down-regulation of other splicing factors, led to clustering of NPCs. Down-regulation of Sm proteins also led to incomplete disassembly of NPCs during mitosis, but had no effect on lamina disassembly, suggesting that the defect in NPC disassembly was not due to a general defect in nuclear envelope breakdown. We further found that these mitotic NPC remnants persisted on an ER membrane that juxtaposes the mitotic spindle. At the end of mitosis, the remnant NPCs moved toward the chromatin and the reforming NE, where they ultimately clustered by forming membrane stacks perforated by NPCs. Our results suggest a novel, splicing-independent, role for Sm proteins in NPC disassembly, and point to a possible link between NPC disassembly in mitosis and NPC distribution in the subsequent interphase.
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Affiliation(s)
- Daphna Joseph-Strauss
- The Laboratory of Molecular and Cellular Biology, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, 8 Center Drive, Bethesda MD 20892, USA
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15
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Borrego-Pinto J, Jegou T, Osorio DS, Auradé F, Gorjánácz M, Koch B, Mattaj IW, Gomes ER. Samp1 is a component of TAN lines and is required for nuclear movement. J Cell Sci 2012; 125:1099-105. [PMID: 22349700 DOI: 10.1242/jcs.087049] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The position of the nucleus is regulated in different developmental stages and cellular events. During polarization, the nucleus moves away from the future leading edge and this movement is required for proper cell migration. Nuclear movement requires the LINC complex components nesprin-2G and SUN2, which form transmembrane actin-associated nuclear (TAN) lines at the nuclear envelope. Here we show that the nuclear envelope protein Samp1 (NET5) is involved in nuclear movement during fibroblast polarization and migration. Moreover, we demonstrate that Samp1 is a component of TAN lines that contain nesprin-2G and SUN2. Finally, Samp1 associates with SUN2 and lamin A/C, and the presence of Samp1 at the nuclear envelope requires lamin A/C. These results support a role for Samp1 in the association between the LINC complex and lamins during nuclear movement.
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16
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Abstract
The nuclear envelope (NE) is a double lipid bilayer that separates nucleus and cytoplasm. In metazoa, NE breakdown (NEBD) occurs during prophase and NE reformation around segregated chromatids occurs at anaphase-telophase. We identified Caenorhabditis elegans Lipin homologue (called Lpin-1) as an essential factor with roles in endoplasmic reticulum (ER) organization and NEBD. RNAi-mediated downregulation of Lpin-1 had no effect on timely entry into mitosis or on the early steps of NEBD, but Lpin-1 was required for disassembly of the nuclear lamina during late NEBD. This Lpin-1 requirement appears to be separable from the effect of Lpin-1 on the peripheral ER.
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Affiliation(s)
- Mátyás Gorjánácz
- European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117, Heidelberg, Germany
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17
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Abstract
The nuclear envelope (NE) of the eukaryotic cell provides an essential barrier that separates the nuclear compartment from the cytoplasm. In addition, the NE is involved in essential functions such as nuclear stability, regulation of gene expression, centrosome separation and nuclear migration and positioning. In metazoa the NE breaks down and re-assembles around the segregated chromatids during each cell division. In this review we discuss the molecular constituents of the Caenorhabditis elegans NE and describe their role in post-mitotic NE re-formation, as well as the usefulness of C. elegans as an in vivo system for analyzing NE dynamics.
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Affiliation(s)
- Mátyás Gorjánácz
- European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
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18
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Gorjánácz M, Klerkx EPF, Galy V, Santarella R, López-Iglesias C, Askjaer P, Mattaj IW. Caenorhabditis elegans BAF-1 and its kinase VRK-1 participate directly in post-mitotic nuclear envelope assembly. EMBO J 2006; 26:132-43. [PMID: 17170708 PMCID: PMC1782363 DOI: 10.1038/sj.emboj.7601470] [Citation(s) in RCA: 164] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2006] [Accepted: 11/06/2006] [Indexed: 01/23/2023] Open
Abstract
Barrier-to-autointegration factor (BAF) is an essential, highly conserved, metazoan protein. BAF interacts with LEM (LAP2, emerin, MAN1) domain-carrying proteins of the inner nuclear membrane. We analyzed the in vivo function of BAF in Caenorhabditis elegans embryos using both RNA interference and a temperature-sensitive baf-1 gene mutation and found that BAF is directly involved in nuclear envelope (NE) formation. NE defects were observed independent of and before the chromatin organization phenotype previously reported in BAF-depleted worms and flies. We identified vaccinia-related kinase (VRK) as a regulator of BAF phosphorylation and localization. VRK localizes both to the NE and chromatin in a cell-cycle-dependent manner. Depletion of VRK results in several mitotic defects, including impaired NE formation and BAF delocalization. We propose that phosphorylation of BAF by VRK plays an essential regulatory role in the association of BAF with chromatin and nuclear membrane proteins during NE formation.
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Affiliation(s)
| | - Elke P F Klerkx
- Institute for Research in Biomedicine, Barcelona Science Park IRB-PCB, Barcelona, Spain
| | - Vincent Galy
- European Molecular Biology Laboratory, Heidelberg, Germany
| | | | | | - Peter Askjaer
- European Molecular Biology Laboratory, Heidelberg, Germany
- Institute for Research in Biomedicine, Barcelona Science Park IRB-PCB, Barcelona, Spain
- Cell Division Group, Institute for Research in Biomedicine, Parc Cientific de Barcelona, C/Josep Samitier 1-5, Barcelona 08028, Spain. Tel.: +34 93 403 70 18; Fax: +34 93 403 71 09; E-mail:
| | - Iain W Mattaj
- European Molecular Biology Laboratory, Heidelberg, Germany
- European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany; E-mail:
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19
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Gorjánácz M, Török I, Pomozi I, Garab G, Szlanka T, Kiss I, Mechler BM. Domains of Importin-alpha2 required for ring canal assembly during Drosophila oogenesis. J Struct Biol 2006; 154:27-41. [PMID: 16458020 DOI: 10.1016/j.jsb.2005.12.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2005] [Revised: 11/10/2005] [Accepted: 12/07/2005] [Indexed: 10/25/2022]
Abstract
Null-mutation in Drosophila importin-alpha2, such as the deficiency imp-alpha2(D14), causes recessive female sterility with the formation of dumpless eggs. In imp-alpha2(D14) the transfer of nurse cell components to the oocyte is interrupted and the Kelch protein, an oligomeric ring canal actin organizer, is normally produced but fails to associate with the ring canals resulting in their occlusion. To define domains regulating Kelch deposition on ring canals we performed site-directed mutagenesis on protein binding domains and putative phosphorylation sites of Imp-alpha2. Phenotypic analysis of the mutant transgenes in imp-alpha2(D14) revealed that mutations affecting the Imp-beta binding-domain, the dimerization domain, and specific serine residues of putative phosphorylation sites led to a normal or nearly normal oogenesis but arrested early embryonic development, whereas mutations in the nuclear localization signal (NLS) and CAS/exportin binding domains resulted in ring canal occlusion and a drastic nuclear accumulation of the mutant proteins. Deletion of the Imp-beta binding domain also gave rise to a nuclear localization of the mutant protein, which partially retained its function in ring canal assembly. Thus, we propose that mutations in NLS and CAS binding domains affect the deposition of Kelch onto the ring canals and prevent the association of Imp-alpha2 with a negative regulator of Kelch function.
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Affiliation(s)
- Mátyás Gorjánácz
- Institute of Genetics, Biological Research Center of the Hungarian Academy of Sciences, Szeged, Hungary
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20
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Gorjánácz M, Adám G, Török I, Mechler BM, Szlanka T, Kiss I. Importin-alpha 2 is critically required for the assembly of ring canals during Drosophila oogenesis. Dev Biol 2002; 251:271-82. [PMID: 12435357 DOI: 10.1006/dbio.2002.0827] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The interstitial deletion D14 affecting the importin-alpha 2 gene of Drosophila, or imp-alpha 2(D14), causes recessive female sterility characterized by a block of nurse cell-oocyte transport during oogenesis. In wild-type egg chambers, the Imp-alpha 2 protein is uniformly distributed in the nurse cell cytoplasm with a moderate accumulation along the oocyte cortex. Cytochalasin D treatment of wild-type egg chambers disrupts the in vivo association of Imp-alpha 2 with F-actin and results in its release from the oocyte cortex and its transfer into nurse cell nuclei. Binding assay shows that the interaction of Imp-alpha 2 with F-actin, albeit not monomeric actin, requires the occurrence of NLS peptides. Phenotypic analysis of imp-alpha 2(D14) ovaries reveals that the block of nurse cell-oocyte transport results from the occlusion of the ring canals that constitute cytoplasmic bridges between the nurse cells and the oocyte. Immunohistochemistry shows that, although the Imp-alpha2 protein cannot be detected on the ring canals, the Kelch protein, a known ring canal component, fails to bind to ring canals in imp-alpha 2(D14) egg chambers. Since loss-of-function mutations of kelch results in a similar dumpless phenotype, we propose that the Imp-alpha 2 protein plays a critical role in Kelch function by regulating its deposition on ring canals during their assembly.
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Affiliation(s)
- Mátyás Gorjánácz
- Institute of Genetics, Biological Research Center of the Hungarian Academy of Sciences, Szeged, Hungary
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21
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Abstract
Importin-alpha proteins do not only mediate the nuclear import of karyophilic proteins but also regulate spindle assembly during mitosis and the assembly of ring canals during Drosophila oogenesis. Three importin-alpha genes are present in the genome of Drosophila. To gain further insights into their function we analysed their expression during spermatogenesis by using antibodies raised against each of the three Importin-alpha proteins identified in Drosophila, namely, Imp-alpha1, -alpha2, and -alpha3. We found that each Imp-alpha is expressed during a specific and limited period of spermatogenesis. Strong expression of Imp-alpha2 takes place in spermatogonial cells, persists in spermatocytes, and lasts up to the completion of meiosis. In growing spermatocytes, the intracellular localisation of Imp-alpha2 appears to be dependent upon the rate of cell growth. In pupal testes Imp-alpha2 is essentially present in the spermatocyte nucleus but is localised in the cytoplasm of spermatocytes from adult testes. Both Imp-alpha1 and -alpha3 expression initiates at the beginning of meiosis and ends during spermatid differentiation. Imp-alpha1 expression extends up to the onset of the elongation phase, whereas that of Imp-alpha3 persists up to the completion of nuclear condensation when the spermatids become individualised. During meiosis Imp-alpha1 and -alpha3 are dispersed in the karyoplasm where they are partially associated with the nuclear spindle, albeit not with the asters. At telophase they aggregate around the chromatin. During sperm head differentiation, both Imp-alpha1 and -alpha3 are nuclear. These data indicate that each Imp-alpha protein carries during Drosophila spermatogenesis distinct, albeit overlapping, functions that may involve nuclear import of proteins, microtubule organisation, and other yet unknown processes.
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Affiliation(s)
- Marianna Giarrè
- Department of Developmental Genetics, Deutsches Krebsforschungszentrum, Im Neuenheimer Feld 280, Heidelberg, Germany
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22
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Török T, Gorjánácz M, Bryant PJ, Kiss I. Prod is a novel DNA-binding protein that binds to the 1.686 g/cm(3) 10 bp satellite repeat of Drosophila melanogaster. Nucleic Acids Res 2000; 28:3551-7. [PMID: 10982875 PMCID: PMC110743 DOI: 10.1093/nar/28.18.3551] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The proliferation disrupter (prod) gene of Drosophila melanogaster encodes a novel protein associated with centromeric chromosomal regions that is required for chromatin condensation and cell viability. We have examined the binding of the Prod protein to DNA in vitro. Co-immunoprecipitation experiments demonstrate that Prod is a DNA-binding protein that specifically recognizes the 10 bp AGAATAACAT satellite repeat of D.melanogaster. Footprinting experiments show that the protein interacts with a 5-8 bp target sequence in each 10 bp repeat and suggest that it can mediate condensation of this satellite into a superhelix. Gel retardation experiments indicate that Prod does not have a well defined DNA-binding domain and it binds the satellite in a co-operative manner, probably forming Prod multimers. Since Prod localizes to both heterochromatin and euchromatin in vivo, we discuss the possibility that the ability of pre-existing euchromatic proteins to bind DNA in a co-operative manner, might be a prerequisite of satellite compaction and satellite amplification, thereby providing a basic factor in heterochromatin evolution.
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Affiliation(s)
- T Török
- Institute of Genetics, Biological Research Center of the Hungarian Academy of Sciences, Szeged H-6701, Hungary.
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