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Tang M, Burgess JT, Fisher M, Boucher D, Bolderson E, Gandhi NS, O'Byrne KJ, Richard DJ, Suraweera A. Targeting the COMMD4-H2B protein complex in lung cancer. Br J Cancer 2023; 129:2014-2024. [PMID: 37914802 PMCID: PMC10703884 DOI: 10.1038/s41416-023-02476-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 10/11/2023] [Accepted: 10/18/2023] [Indexed: 11/03/2023] Open
Abstract
BACKGROUND Lung cancer is the biggest cause of cancer-related deaths worldwide. Non-small cell lung cancer (NSCLC) accounts for 85-90% of all lung cancers. Identification of novel therapeutic targets are required as drug resistance impairs chemotherapy effectiveness. COMMD4 is a potential NSCLC therapeutic target. The aims of this study were to investigate the COMMD4-H2B binding pose and develop a short H2B peptide that disrupts the COMMD4-H2B interaction and mimics COMMD4 siRNA depletion. METHODS Molecular modelling, in vitro binding and site-directed mutagenesis were used to identify the COMMD4-H2B binding pose and develop a H2B peptide to inhibit the COMMD4-H2B interaction. Cell viability, DNA repair and mitotic catastrophe assays were performed to determine whether this peptide can specially kill NSCLC cells. RESULTS Based on the COMMD4-H2B binding pose, we have identified a H2B peptide that inhibits COMMD4-H2B by directly binding to COMMD4 on its H2B binding binding site, both in vitro and in vivo. Treatment of NSCLC cell lines with this peptide resulted in increased sensitivity to ionising radiation, increased DNA double-strand breaks and induction of mitotic catastrophe in NSCLC cell lines. CONCLUSIONS Our data shows that COMMD4-H2B represents a novel potential NSCLC therapeutic target.
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Affiliation(s)
- Ming Tang
- Queensland University of Technology (QUT), School of Biomedical Sciences, Centre for Genomics and Personalised Health at the Translational Research Institute, 37 Kent Street, Woolloongabba, QLD, 4102, Australia
- Frazer Institute, Faculty of Medicine, The University of Queensland at the Translational Research Institute, 37 Kent Street, Woolloongabba, QLD, 4102, Australia
| | - Joshua T Burgess
- Queensland University of Technology (QUT), School of Biomedical Sciences, Centre for Genomics and Personalised Health at the Translational Research Institute, 37 Kent Street, Woolloongabba, QLD, 4102, Australia
- Princess Alexandra Hospital, 199 Ipswich Road, Woolloongabba, QLD, 4102, Australia
| | - Mark Fisher
- Queensland University of Technology (QUT), School of Biomedical Sciences, Centre for Genomics and Personalised Health at the Translational Research Institute, 37 Kent Street, Woolloongabba, QLD, 4102, Australia
| | - Didier Boucher
- Queensland University of Technology (QUT), School of Biomedical Sciences, Centre for Genomics and Personalised Health at the Translational Research Institute, 37 Kent Street, Woolloongabba, QLD, 4102, Australia
- Princess Alexandra Hospital, 199 Ipswich Road, Woolloongabba, QLD, 4102, Australia
| | - Emma Bolderson
- Queensland University of Technology (QUT), School of Biomedical Sciences, Centre for Genomics and Personalised Health at the Translational Research Institute, 37 Kent Street, Woolloongabba, QLD, 4102, Australia
- Princess Alexandra Hospital, 199 Ipswich Road, Woolloongabba, QLD, 4102, Australia
| | - Neha S Gandhi
- Queensland University of Technology (QUT), School of Biomedical Sciences, Centre for Genomics and Personalised Health at the Translational Research Institute, 37 Kent Street, Woolloongabba, QLD, 4102, Australia
- Department of Computer Science and Engineering, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal, Udupi, Karnataka, 576104, India
| | - Kenneth J O'Byrne
- Queensland University of Technology (QUT), School of Biomedical Sciences, Centre for Genomics and Personalised Health at the Translational Research Institute, 37 Kent Street, Woolloongabba, QLD, 4102, Australia.
- Princess Alexandra Hospital, 199 Ipswich Road, Woolloongabba, QLD, 4102, Australia.
| | - Derek J Richard
- Queensland University of Technology (QUT), School of Biomedical Sciences, Centre for Genomics and Personalised Health at the Translational Research Institute, 37 Kent Street, Woolloongabba, QLD, 4102, Australia.
- Princess Alexandra Hospital, 199 Ipswich Road, Woolloongabba, QLD, 4102, Australia.
| | - Amila Suraweera
- Queensland University of Technology (QUT), School of Biomedical Sciences, Centre for Genomics and Personalised Health at the Translational Research Institute, 37 Kent Street, Woolloongabba, QLD, 4102, Australia.
- Princess Alexandra Hospital, 199 Ipswich Road, Woolloongabba, QLD, 4102, Australia.
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Liu Z, Jin D, Wei X, Gao Y, Gao X, Li X, Wang X, Wei P, Liu T. ZBTB34 is a hepatocellular carcinoma-associated protein with a monopartite nuclear localization signal. Aging (Albany NY) 2023; 15:8487-8500. [PMID: 37650557 PMCID: PMC10496988 DOI: 10.18632/aging.204987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Accepted: 07/18/2023] [Indexed: 09/01/2023]
Abstract
ZBTB34 is a novel zinc finger protein with an unknown function. In this study, the gene expression and survival prognosis of ZBTB34 were analyzed across tumors based on the TCGA datasets. According to the bioinformatics analysis and qPCR results, liver hepatocellular carcinomas exhibit a high level of ZBTB34 expression. Additionally, the experiment supported the bioinformatics analysis findings that ZBTB34 expression was regulated by miR-125b-5p and that ZBTB34 affected ZBTB10, POLR1B, and AUH expression in HepG2 cells. Biological software analysis further revealed that ZBTB34 contains a monopartite nuclear localization signal (NLS). Arginine and lysine inside the putative NLS were substituted using the alanine-scanning mutagenesis method. The findings showed that the ability of ZBTB34 to enter the nucleus was abolished by the alanine substitution of the sequence 320RGGRARQKRA329 and the mutation of Lys327 and Arg328 residues. ZBTB34 was co-immunoprecipitated with importin α1, importin α3, importin α4, and importin β1, according to the results of the co-immunoprecipitation assay. In conclusion, ZBTB34 is a hepatocellular carcinoma-associated protein with a monopartite NLS. The nuclear import of ZBTB34 is mediated by importin α1, importin α3, importin α4, and importin β1. ZBTB34 performs its biological functions via a putative miR-125b-5p/ZBTB34/(ZBTB10, POLR1B, and AUH) signaling axis in HepG2 cells.
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Affiliation(s)
- Zheng Liu
- College of Medical Laboratory Science, Guilin Medical University, Guilin 541004, Guangxi, China
- Guihang Guiyang Hospital Affiliated to Zunyi Medical University, Guiyang 550027, Guizhou, China
| | - Di Jin
- College of Medical Laboratory Science, Guilin Medical University, Guilin 541004, Guangxi, China
| | - Xinran Wei
- College of Medical Laboratory Science, Guilin Medical University, Guilin 541004, Guangxi, China
| | - Yue Gao
- College of Medical Laboratory Science, Guilin Medical University, Guilin 541004, Guangxi, China
| | - Xiaodie Gao
- College of Medical Laboratory Science, Guilin Medical University, Guilin 541004, Guangxi, China
| | - Xia Li
- Clinical Laboratory, Hospital Affiliated to Guilin Medical University, Guilin 541001, Guangxi, China
| | - Xiujuan Wang
- College of Medical Laboratory Science, Guilin Medical University, Guilin 541004, Guangxi, China
| | - Pingying Wei
- College of Medical Laboratory Science, Guilin Medical University, Guilin 541004, Guangxi, China
| | - Tao Liu
- Guihang Guiyang Hospital Affiliated to Zunyi Medical University, Guiyang 550027, Guizhou, China
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3
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Rizzuti B, Iovanna JL, Neira JL. Deciphering the Binding of the Nuclear Localization Sequence of Myc Protein to the Nuclear Carrier Importin α3. Int J Mol Sci 2022; 23:ijms232315333. [PMID: 36499669 PMCID: PMC9739371 DOI: 10.3390/ijms232315333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 11/29/2022] [Accepted: 12/02/2022] [Indexed: 12/12/2022] Open
Abstract
The oncoprotein Myc is a transcription factor regulating global gene expression and modulating cell proliferation, apoptosis, and metabolism. Myc has a nuclear localization sequence (NLS) comprising residues Pro320 to Asp328, to allow for nuclear translocation. We designed a peptide comprising such region and the flanking residues (Ala310-Asn339), NLS-Myc, to study, in vitro and in silico, the ability to bind importin α3 (Impα3) and its truncated species (ΔImpα3) depleted of the importin binding domain (IBB), by using fluorescence, circular dichroism (CD), biolayer interferometry (BLI), nuclear magnetic resonance (NMR), and molecular simulations. NLS-Myc interacted with both importin species, with affinity constants of ~0.5 µM (for Impα3) and ~60 nM (for ΔImpα3), as measured by BLI. The molecular simulations predicted that the anchoring of NLS-Myc took place in the major binding site of Impα3 for the NLS of cargo proteins. Besides clarifying the conformational behavior of the isolated NLS of Myc in solution, our results identified some unique properties in the binding of this localization sequence to the nuclear carrier Impα3, such as a difference in the kinetics of its release mechanism depending on the presence or absence of the IBB domain.
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Affiliation(s)
- Bruno Rizzuti
- CNR-NANOTEC, SS Rende (CS), Department of Physics, University of Calabria, 87036 Rende, Italy
- Instituto de Biocomputación y Física de Sistemas Complejos–Unidad Mixta GBsC-CSIC-BIFI, Universidad de Zaragoza, 50018 Zaragoza, Spain
- Correspondence: (B.R.); (J.L.N.)
| | - Juan L. Iovanna
- Centre de Recherche en Cancérologie de Marseille (CRCM), INSERM U1068, CNRS UMR 7258, Institut Paoli-Calmettes, Aix-Marseille Université, 13288 Marseille, France
| | - José L. Neira
- Instituto de Biocomputación y Física de Sistemas Complejos–Unidad Mixta GBsC-CSIC-BIFI, Universidad de Zaragoza, 50018 Zaragoza, Spain
- Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDIBE), Universidad Miguel Hernández, 03202 Elche, Spain
- Correspondence: (B.R.); (J.L.N.)
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Mentrup T, Häsler R, Fluhrer R, Saftig P, Schröder B. A Cell-Based Assay Reveals Nuclear Translocation of Intracellular Domains Released by SPPL Proteases. Traffic 2015; 16:871-92. [DOI: 10.1111/tra.12287] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Revised: 03/26/2015] [Accepted: 03/26/2015] [Indexed: 12/27/2022]
Affiliation(s)
- Torben Mentrup
- Biochemical Institute; Christian Albrechts University of Kiel; Otto-Hahn-Platz 9 D-24118 Kiel Germany
| | - Robert Häsler
- Institute of Clinical Molecular Biology; Christian Albrechts University of Kiel; Schittenhelmstr. 12 D-24105 Kiel Germany
| | - Regina Fluhrer
- Biomedizinisches Centrum (BMC); Ludwig Maximilians University of Munich; Feodor-Lynen-Strasse 17 D-81377 Munich Germany
- DZNE - German Center for Neurodegenerative Diseases; Feodor-Lynen-Strasse 17 D-81377 Munich Germany
| | - Paul Saftig
- Biochemical Institute; Christian Albrechts University of Kiel; Otto-Hahn-Platz 9 D-24118 Kiel Germany
| | - Bernd Schröder
- Biochemical Institute; Christian Albrechts University of Kiel; Otto-Hahn-Platz 9 D-24118 Kiel Germany
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Wenska M, Alvira M, Steunenberg P, Stenberg Å, Murtola M, Strömberg R. An activated triple bond linker enables 'click' attachment of peptides to oligonucleotides on solid support. Nucleic Acids Res 2011; 39:9047-59. [PMID: 21795380 PMCID: PMC3203603 DOI: 10.1093/nar/gkr603] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2010] [Revised: 07/05/2011] [Accepted: 07/06/2011] [Indexed: 11/13/2022] Open
Abstract
A general procedure, based on a new activated alkyne linker, for the preparation of peptide-oligonucleotide conjugates (POCs) on solid support has been developed. With this linker, conjugation is effective at room temperature (RT) in millimolar concentration and submicromolar amounts. This is made possible since the use of a readily attachable activated triple bond linker enhances the Cu(I) catalyzed 1,3-dipolar cycloaddition ('click' reaction). The preferred scheme for conjugate preparation involves sequential conjugation to oligonucleotides on solid support of (i) an H-phosphonate-based aminolinker; (ii) the triple bond donor p-(N-propynoylamino)toluic acid (PATA); and (iii) azido-functionalized peptides. The method gives conversion of oligonucleotide to the POC on solid support, and only involves a single purification step after complete assembly. The synthesis is flexible and can be carried out without the need for specific automated synthesizers since it has been designed to utilize commercially available oligonucleotide and peptide derivatives on solid support or in solution. Methodology for the ready conversion of peptides into 'clickable' azidopeptides with the possibility of selecting either N-terminus or C-terminus connection also adds to the flexibility and usability of the method. Examples of synthesis of POCs include conjugates of oligonucleotides with peptides known to be membrane penetrating and nuclear localization signals.
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Affiliation(s)
- Malgorzata Wenska
- Department of Biosciences and Nutrition, Karolinska Institutet, Novum, SE-141 83 Huddinge, Sweden
| | | | | | | | | | - Roger Strömberg
- Department of Biosciences and Nutrition, Karolinska Institutet, Novum, SE-141 83 Huddinge, Sweden
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Patient-derived C-terminal mutation of FANCI causes protein mislocalization and reveals putative EDGE motif function in DNA repair. Blood 2010; 117:2247-56. [PMID: 20971953 DOI: 10.1182/blood-2010-07-295758] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Fanconi anemia (FA) is a rare familial genome instability syndrome caused by mutations in FA genes that results in defective DNA crosslink repair. Activation of the FA pathway requires the FA core ubiquitin ligase complex-dependent monoubiquitination of 2 interacting FA proteins, FANCI and FANCD2. Although loss of either FANCI or FANCD2 is known to prevent monoubiquitination of its respective partner, it is unclear whether FANCI has any additional domains that may be important in promoting DNA repair, independent of its monoubiquitination. Here, we focus on an FA-I patient-derived FANCI mutant protein, R1299X (deletion of 30 residues from its C-terminus), to characterize important structural region(s) in FANCI that is required to activate the FA pathway. We show that, within this short 30 amino acid stretch contains 2 separable functional signatures, a nuclear localization signal and a putative EDGE motif, that is critical for the ability of FANCI to properly monoubiquitinate FANCD2 and promote DNA crosslink resistance. Our study enable us to conclude that, although proper nuclear localization of FANCI is crucial for robust FANCD2 monoubiquitination, the putative FANCI EDGE motif is important for DNA crosslink repair.
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Zhu PJ, Zheng W, Auld DS, Jadhav A, Macarthur R, Olson KR, Peng K, Dotimas H, Austin CP, Inglese J. A miniaturized glucocorticoid receptor translocation assay using enzymatic fragment complementation evaluated with qHTS. Comb Chem High Throughput Screen 2009; 11:545-59. [PMID: 18694391 DOI: 10.2174/138620708785204045] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Nuclear translocation is an important step in glucocorticoid receptor (GR) signaling and assays that measure this process allow the identification of nuclear receptor ligands independent of subsequent functional effects. To facilitate the identification of GR-translocation agonists, an enzyme fragment complementation (EFC) cell-based assay was scaled to a 1536-well plate format to evaluate 9,920 compounds using a quantitative high throughput screening (qHTS) strategy where compounds are assayed at multiple concentrations. In contrast to conventional assays of nuclear translocation the qHTS assay described here was enabled on a standard luminescence microplate reader precluding the requirement for imaging methods. The assay uses beta-galactosidase alpha complementation to indirectly detect GR-translocation in CHO-K1 cells. 1536-well assay miniaturization included the elimination of a media aspiration step, and the optimized assay displayed a Z' of 0.55. qHTS yielded EC(50) values for all 9,920 compounds and allowed us to retrospectively examine the dataset as a single concentration-based screen to estimate the number of false positives and negatives at typical activity thresholds. For example, at a 9 microM screening concentration, the assay showed an accuracy that is comparable to typical cell-based assays as judged by the occurrence of false positives that we determined to be 1.3% or 0.3%, for a 3sigma or 6sigma threshold, respectively. This corresponds to a confirmation rate of approximately 30% or approximately 50%, respectively. The assay was consistent with glucocorticoid pharmacology as scaffolds with close similarity to dexamethasone were identified as active, while, for example, steroids that act as ligands to other nuclear receptors such as the estrogen receptor were found to be inactive.
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Affiliation(s)
- Ping Jun Zhu
- National Institutes of Health, National Human Genome Research Institute, NIH Chemical Genomics Center, Bethesda, MD 20892-3370, USA
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8
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Saito Y, Yamagishi N, Hatayama T. Different localization of Hsp105 family proteins in mammalian cells. Exp Cell Res 2007; 313:3707-17. [PMID: 17643418 DOI: 10.1016/j.yexcr.2007.06.009] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2007] [Revised: 05/18/2007] [Accepted: 06/10/2007] [Indexed: 11/18/2022]
Abstract
Hsp105alpha and Hsp105beta of the HSP105 family are alternatively spliced products derived from an hsp 105 gene transcript. Hsp105alpha is constitutively expressed and also induced by various stress, whereas Hsp105beta, lacking 44 amino acids from Hsp105alpha, is specifically expressed during mild heat shock. Although Hsp105alpha is shown to localize in the cytoplasm of mammalian cells, cellular localization of Hsp105beta is not known. In this study, we showed that Hsp105beta localized in the nucleus of cells in contrast to cytoplasmic Hsp105alpha, suggesting that these proteins function in different cellular compartments of cells. Using deletion and substitution mutants of Hsp105alpha and Hsp105beta, we revealed that these proteins had a functional nuclear localization signal (NLS) and a nuclear export signal (NES). Furthermore, Hsp105alpha accumulated in the nucleus of cells when treated with leptomycin B, a specific inhibitor of NES-dependent nuclear export. siRNA for importin beta, an essential component for NLS-dependent nuclear transport, inhibited the nuclear localization of Hsp105beta. Furthermore, the 44 amino acids sequence found in Hsp105alpha but not in Hsp105beta suppressed the NLS activity. Thus, the different localization of Hsp105alpha and Hsp105beta is suggested to be due to the suppressed NLS activity in Hsp105alpha.
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Affiliation(s)
- Youhei Saito
- Department of Biochemistry, Kyoto Pharmaceutical University, 5 Nakauchi-cho, Misasagi, Yamashina-ku, Kyoto 607-8414, Japan
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9
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Hamlat A, Pasqualini E. Stem cells adaptive network: mechanism and implications for evolution and disease development. Med Hypotheses 2007; 69:610-7. [PMID: 17336463 DOI: 10.1016/j.mehy.2006.12.052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2006] [Accepted: 12/21/2006] [Indexed: 10/23/2022]
Abstract
During development, different cells and tissues acquire different programmes of gene expression, so that cells are related to each other through a somatic cells tree or cluster and adult pluripotential stem cells (PSC) may be defined as progenitors that we distinguish in four types according to their biological behaviour. This clustering may segregate specific pathways establishing spatial patterns of cell-cell communications. Thus, we suggest that normal somatic cells renewal is tributary of multipotential stem cells (MSC), while renewal of cells undergoing stress or abnormal death is tributary of PSC through specific pathway(s) from cluster, thus, defining the cell repertoire that will be produced. We also assume that PSC play a pivotal role in evolutionary and propose the theory of "internal clusters competition". According to the functional duality of stem cells (SC) we define a stem cells adaptive network (SCAN) which we believe is linked to the central clock and display two pathways. The diurnal pathway includes SC-somatic cells communications, while the nocturnal pathway includes inter-SC network. These alternate pathways could be activated or repressed as a consequence of change in the biological chirality. This new approach of SC may contribute to our understanding on how some diseases may develop including cancer which could be linked to "cluster illness", while demyelinating and systemic diseases could be related to "PSC locus illness" or "focalised SCAN disturbances" and it explains how any environment stress may act on organism evolution.
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Affiliation(s)
- Abderrahmane Hamlat
- Department of Neurosurgery, CHRU Pontchaillou, Rue Henry Le Guilloux, 35000 Rennes, Cedex 2, France.
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10
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Abstract
Serum amyloid A (SAA) is a family of proteins encoded by four related genes. Of the four, isoforms 1.1 and 2.1 are acute phase proteins synthesized by the liver. They become major components of the HDL plasma fraction during acute tissue injury and the HDL/SAA complex is readily taken up by macrophages. Herein we investigated the path SAA follows when presented to macrophages as HDL/SAA or in liposomes. Using antibodies specific to SAA and confocal microscopy, or EM autoradiography where only SAA is radio-labeled, we show that HDL/SAA is taken up rapidly by macrophages and within 30 min SAA, or fragments thereof, proceeds through the cytoplasm to the peri-nuclear region and then the nucleus. Within 45-60 min SAA, or fragments thereof, is found back in the cytoplasm and at the plasma membrane where it is subsequently extruded. The observation that SAA, or fragments thereof, traverse the nucleus is a novel finding and may implicate SAA in macrophage gene regulation. It also raises questions by what mechanism SAA enters and leaves the nucleus. We further investigated if both SAA isoforms traffic through the macrophage in a similar manner. Isoform differences were observed. Both isoforms bind well to the plasma membrane of macrophages at 4 degrees C, but at 37 degrees C only SAA2.1 is taken up by the cell in significant quantity, and is observed in the nucleus, suggesting that the two isoforms are handled differently and that they may have discrete physiological roles.
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Affiliation(s)
- Sarah M Kinkley
- Department of Pathology and Molecular Medicine, Queen's University, Kingston, Ontario, Canada
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11
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Fung P, Peng K, Kobel P, Dotimas H, Kauffman L, Olson K, Eglen RM. A Homogeneous Cell-Based Assay to Measure Nuclear Translocation Using β-Galactosidase Enzyme Fragment Complementation. Assay Drug Dev Technol 2006; 4:263-72. [PMID: 16834532 DOI: 10.1089/adt.2006.4.263] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Positional complementation describes the use of homogeneous assays using beta- galactosidase (beta gal) enzyme fragment complementation to detect cellular protein translocation. This phenomenon occurs when the protein of interest, recombinantly expressed as a fusion protein with a modified alpha fragment of beta gal, translocates to a cellular compartment expressing an enzyme acceptor fragment of the enzyme. When these fragments interact, high-affinity complementation occurs, and a signal is generated that is then detected upon cell lysis. In the present paper the use of positional complementation is exemplified by measuring nuclear translocation of the glucocorticoid receptor in Chinese hamster ovary-K1 cells. The approach thus provides for homogeneous protocols, in an endpoint microtiter plate assay format, without the use of either imaging or reporter gene techniques. Consequently, these characteristics suggest that the technique is suitable for automated instrumentation protocols used in high throughput screening campaigns designed to identify activators or inhibitors of nuclear translocation.
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Affiliation(s)
- P Fung
- DiscoveRx Corp., Fremont, CA 94538, USA
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12
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Rosenbluh J, Kapelnikov A, Shalev DE, Rusnati M, Bugatti A, Loyter A. Positively charged peptides can interact with each other, as revealed by solid phase binding assays. Anal Biochem 2006; 352:157-68. [PMID: 16581010 DOI: 10.1016/j.ab.2006.03.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2005] [Revised: 12/19/2005] [Accepted: 03/01/2006] [Indexed: 11/24/2022]
Abstract
Solid phase assay systems such as enzyme-linked immunosorbent assay (ELISA), surface plasmon resonance (SPR), and overlay gels are used to study processes of protein-protein interactions. The common principle of all these methods is that they monitor the binding between soluble and surface-immobilized molecules. Following the use of bovine serum albumin (BSA)-peptide conjugates or isolated synthetic peptides and the above-mentioned solid phase assay systems, the results of the current work demonstrate that positively charged peptides can interact with each other. Both the ELISA and SPR methods demonstrated that the binding process reached saturation with K(d) values ranging between 1 and 14 nM. No interaction was observed between BSA conjugates bearing positively charged peptides and conjugates bearing negatively charged peptides or with pure BSA molecules, strengthening the view that interaction occurs only between positively charged peptides. However, interactions between peptides in solution were not observed by nuclear magnetic resonance (NMR) or by native gel electrophoresis. It appears that for positively charged molecules to interact, one of the binding partners must be immobilized to a surface, a process that may lead to the exposure of otherwise masked groups or atoms. We discuss the relevance of our findings for the use of solid phase assay systems to study interactions between biomolecules.
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Affiliation(s)
- Joseph Rosenbluh
- Department of Biological Chemistry, Alexander Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Safra Campus, Givat Ram, Jerusalem 91904, Israel
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Subramaniam PS, Johnson HM. The IFNAR1 subunit of the type I IFN receptor complex contains a functional nuclear localization sequence. FEBS Lett 2005; 578:207-10. [PMID: 15589821 DOI: 10.1016/j.febslet.2004.10.085] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2004] [Revised: 10/17/2004] [Accepted: 10/28/2004] [Indexed: 11/26/2022]
Abstract
A nuclear localization sequence (NLS) in the type II interferon (IFN) IFN gamma, which is responsible for the nuclear translocation of both the ligand and the alpha-subunit (IFNGR1) of the receptor complex, has previously been characterized and its role in signaling examined in detail. We have now identified an NLS in the type I IFN receptor (IFNAR) common subunit IFNAR1 from humans and show that the human IFNAR1 subunit can translocate to the nucleus following human IFN beta stimulation. An NLS in human IFNAR1 is located in the extracellular domain of IFNAR1 within the sequence (382)RKIIEKKT (numbered for the precursor form). Nuclear import by the NLS functions in a conventional fashion requiring cytosolic import factors, is energy-dependent and inhibited by the prototypical NLS of the SV40 large T-antigen. These studies provide a mechanism for nuclear import of IFNAR1, as well as for type I IFN ligands, and a starting point for studying an alternate role for IFNAR1 in nuclear signaling within the type I IFN system.
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Affiliation(s)
- Prem S Subramaniam
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL, USA.
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Lee SJ, Sekimoto T, Yamashita E, Nagoshi E, Nakagawa A, Imamoto N, Yoshimura M, Sakai H, Chong KT, Tsukihara T, Yoneda Y. The structure of importin-beta bound to SREBP-2: nuclear import of a transcription factor. Science 2003; 302:1571-5. [PMID: 14645851 DOI: 10.1126/science.1088372] [Citation(s) in RCA: 169] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The sterol regulatory element-binding protein 2 (SREBP-2), a nuclear transcription factor that is essential for cholesterol metabolism, enters the nucleus through a direct interaction of its helix-loop-helix leucine zipper domain with importin-beta. We show the crystal structure of importin-beta complexed with the active form of SREBP-2. Importin-beta uses characteristic long helices like a pair of chopsticks to interact with an SREBP-2 dimer. Importin-beta changes its conformation to reveal a pseudo-twofold symmetry on its surface structure so that it can accommodate a symmetric dimer molecule. Importin-beta may use a similar strategy to recognize other dimeric cargoes.
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Affiliation(s)
- Soo Jae Lee
- Institute for Protein Research, Graduate School of Frontier Biosciences, Osaka University, Yamadaoka 2-2, Suita, Osaka 565-0871, Japan
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15
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Carystinos GD, Kandouz M, Alaoui-Jamali MA, Batist G. Unexpected induction of the human connexin 43 promoter by the ras signaling pathway is mediated by a novel putative promoter sequence. Mol Pharmacol 2003; 63:821-31. [PMID: 12644583 DOI: 10.1124/mol.63.4.821] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Connexin 43 (Cx43) is essential for survival and is tightly regulated at the transcriptional and post-transcriptional levels. A number of previous studies have demonstrated altered expression in malignant tissues, and in the presence of carcinogenic factors. We examined the effect of protooncogenes of Cx43 expression, and found no effect on Cx43 promoter activity in cells transformed with Src or erbB2. On the other hand, we identified and characterized a novel sequence that mediates Cx43 promoter regulation in cell lines engineered to overexpress H-Ras. Compared with wild-type NIH3T3 cells, both Cx43 mRNA and protein levels are increased in NIH3T3-Ras cells. The H-Ras+ cells also have enhanced Cx43 promoter activation, which is inhibited by the MEK1 inhibitor 2'-amino-3'-methoxyflavone (PD98059), suggesting that Ras-mediated Cx43 overexpression is via the mitogen activated protein kinase kinase/extracellular signal-regulated pathway. Deletion analysis of the Cx43 promoter revealed a 200-bp region downstream of the Cx43 transcription start site as the minimal sequence essential for the Ras-mediated Cx43 up-regulation. Using this 200-base pair fragment in electrophoretic mobility shift assays, we identified one main protein complex that binds efficiently and is more abundant in nuclear extracts from NIH3T3-Ras and MCF7-Ras cells compared with their matched controls. This complex selectively recognizes a consensus sequence, AGTTCAATCA, located at positions +149 to +158 of the Cx43 promoter. Supershift assays identified the 90-kDa heat shock protein (HSP90) and c-Myc as constituents of this DNA-binding complex. Treatment of cells with the HSP90 inhibitor geldanamycin resulted in repression of the Cx43 promoter activity, and inhibits binding of the complex to the Cx43 promoter. Coimmunoprecipitation studies confirmed the interaction between endogenous HSP90 and c-Myc. This study provides evidence that the transcriptional up-regulation of Cx43 by Ras-Raf-MAPK is mediated via the interaction of a novel Cx43 promoter element with a protein complex that contains both HSP90 and c-Myc.
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Affiliation(s)
- George D Carystinos
- Department of Pharmacology & Therapeutics and the Montreal Centre for Experimental Therapeutics in Cancer, Lady Davis Institute of the Sir Mortimer B. Davis-Jewish General Hospital, McGill University, Montreal, Canada
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16
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Abstract
c-MYC is the prototype for oncogene activation by chromosomal translocation. In contrast to the tightly regulated expression of c-myc in normal cells, c-myc is frequently deregulated in human cancers. Herein, aspects of c-myc gene activation and the function of the c-Myc protein are reviewed. The c-myc gene produces an oncogenic transcription factor that affects diverse cellular processes involved in cell growth, cell proliferation, apoptosis and cellular metabolism. Complete removal of c-myc results in slowed cell growth and proliferation, suggesting that while c-myc is not required for cell proliferation, it acts as an integrator and accelerator of cellular metabolism and proliferation.
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Affiliation(s)
- L M Boxer
- Division of Hematology, Department of Medicine, Stanford University School of Medicine, Stanford, California CA 94305, USA
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17
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Christophe D, Christophe-Hobertus C, Pichon B. Nuclear targeting of proteins: how many different signals? Cell Signal 2000; 12:337-41. [PMID: 10822175 DOI: 10.1016/s0898-6568(00)00077-2] [Citation(s) in RCA: 140] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The nuclear import of proteins into the cell nucleus involves the recognition of a nuclear localization signal sequence, borne by the protein to be transported, by complex molecules called importins, that will subsequently mediate the crossing over of the nuclear envelope. The most frequently encountered signal sequence is made up of short stretches of basic amino acid residues and is recognized by importins alpha and/or beta. Other signal sequences have been described, and some have been shown to mediate the association with importins other than importin alpha or beta. Recently, approaches have been developed that allow the cloning, on a functional basis, of sequences able to specify the nuclear localization of proteins. A variety of peptidic motifs of limited size which do not contain previously described signal sequences were isolated in such assays. It reveals that the spectrum of sequences that are able to target a protein to the cell nucleus may be wider than currently expected. It will probably also lead to the identification of novel target sequences for importins and will demonstrate the implication of additional members of this family of proteins in nuclear transport.
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Affiliation(s)
- D Christophe
- Institut de Biologie et de Médecine Moléculaires (IBMM), IRIBHN-Faculté de Médecine, Université Libre de Bruxelles, rue des Professeurs Jeener et Brachet 12, 6041, Gosselies, Belgique.
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18
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Cutrona G, Carpaneto EM, Ulivi M, Roncella S, Landt O, Ferrarini M, Boffa LC. Effects in live cells of a c-myc anti-gene PNA linked to a nuclear localization signal. Nat Biotechnol 2000; 18:300-3. [PMID: 10700145 DOI: 10.1038/73745] [Citation(s) in RCA: 165] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Peptide nucleic acids (PNA) are synthetic homologs of nucleic acids in which the phosphate-sugar polynucleotide backbone is replaced by a flexible polyamide. In this study, a PNA construct was employed as an anti-gene agent in intact cells in culture. The cell lines studied were derived from Burkitt's lymphomas (BL) that presented a translocated and hyperexpressed c-myc oncogene. A 17-mer anti-myc PNA, complementary to a unique sequence located at the beginning of the second exon of the oncogene, and was covalently linked at its N terminus to a nuclear localization signal (NLS) (PNA-myc(wt)-NLS). When BL cells were exposed to PNA-myc(wt)-NLS, the anti-gene construct was localized predominantly in the cell nuclei and a rapid consequent downregulation of c-myc expression occurred. Under these conditions, both completion of a productive cell cycle and apoptosis were inhibited.
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Affiliation(s)
- G Cutrona
- Servizi di Immunologia Clinica, National Cancer Institute, Genoa, Italy
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19
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Nagoshi E, Imamoto N, Sato R, Yoneda Y. Nuclear import of sterol regulatory element-binding protein-2, a basic helix-loop-helix-leucine zipper (bHLH-Zip)-containing transcription factor, occurs through the direct interaction of importin beta with HLH-Zip. Mol Biol Cell 1999; 10:2221-33. [PMID: 10397761 PMCID: PMC25438 DOI: 10.1091/mbc.10.7.2221] [Citation(s) in RCA: 98] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The sterol regulatory element-binding protein-2 (SREBP-2) is produced as a large precursor molecule attached to the endoplasmic reticulum membrane. In response to the sterol depletion, the N-terminal segment of the precursor, which contains a basic helix-loop-helix-leucine zipper domain, is released by two sequential cleavages and is translocated to the nucleus, where it activates the transcription of target genes. The data herein show that released SREBP-2 uses a distinct nuclear transport pathway, which is mediated by importin beta. The mature form of SREBP-2 is actively transported into the nucleus when injected into the cell cytoplasm. SREBP-2 binds directly to importin beta in the absence of importin alpha. Ran-GTP but not Ran-GDP causes the dissociation of the SREBP-2-importin beta complex. G19VRan-GTP inhibits the nuclear import of SREBP-2 in living cells. In the permeabilized cell in vitro transport system, nuclear import of SREBP-2 is reconstituted only by importin beta in conjunction with Ran and its interacting protein p10/NTF2. We further demonstrate that the helix-loop-helix-leucine zipper motif of SREBP-2 contains a novel type of nuclear localization signal, which binds directly to importin beta.
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Affiliation(s)
- E Nagoshi
- Department of Anatomy and Cell Biology, Osaka University Medical School, Osaka 565-0871, Japan
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