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Mende H, Khatri A, Lange C, Poveda-Cuevas SA, Tascher G, Covarrubias-Pinto A, Löhr F, Koschade SE, Dikic I, Münch C, Bremm A, Brunetti L, Brandts CH, Uckelmann H, Dötsch V, Rogov VV, Bhaskara RM, Müller S. An atypical GABARAP binding module drives the pro-autophagic potential of the AML-associated NPM1c variant. Cell Rep 2023; 42:113484. [PMID: 37999976 DOI: 10.1016/j.celrep.2023.113484] [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: 03/29/2023] [Revised: 09/22/2023] [Accepted: 11/08/2023] [Indexed: 11/26/2023] Open
Abstract
The nucleolar scaffold protein NPM1 is a multifunctional regulator of cellular homeostasis, genome integrity, and stress response. NPM1 mutations, known as NPM1c variants promoting its aberrant cytoplasmic localization, are the most frequent genetic alterations in acute myeloid leukemia (AML). A hallmark of AML cells is their dependency on elevated autophagic flux. Here, we show that NPM1 and NPM1c induce the autophagy-lysosome pathway by activating the master transcription factor TFEB, thereby coordinating the expression of lysosomal proteins and autophagy regulators. Importantly, both NPM1 and NPM1c bind to autophagy modifiers of the GABARAP subfamily through an atypical binding module preserved within its N terminus. The propensity of NPM1c to induce autophagy depends on this module, likely indicating that NPM1c exerts its pro-autophagic activity by direct engagement with GABARAPL1. Our data report a non-canonical binding mode of GABARAP family members that drives the pro-autophagic potential of NPM1c, potentially enabling therapeutic options.
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Affiliation(s)
- Hannah Mende
- Goethe University Frankfurt, Institute of Biochemistry II, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany
| | - Anshu Khatri
- Goethe University Frankfurt, Institute of Biophysical Chemistry and Center for Biomolecular Magnetic Resonance, Max-von-Laue Street 9, 60438 Frankfurt, Germany
| | - Carolin Lange
- Goethe University Frankfurt, Institute of Biochemistry II, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany; Goethe University Frankfurt, Buchmann Institute for Molecular Life Sciences, Max-von-Laue Street 15, 60438 Frankfurt, Germany
| | - Sergio Alejandro Poveda-Cuevas
- Goethe University Frankfurt, Institute of Biochemistry II, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany; Goethe University Frankfurt, Buchmann Institute for Molecular Life Sciences, Max-von-Laue Street 15, 60438 Frankfurt, Germany
| | - Georg Tascher
- Goethe University Frankfurt, Institute of Biochemistry II, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany
| | - Adriana Covarrubias-Pinto
- Goethe University Frankfurt, Institute of Biochemistry II, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany
| | - Frank Löhr
- Goethe University Frankfurt, Institute of Biophysical Chemistry and Center for Biomolecular Magnetic Resonance, Max-von-Laue Street 9, 60438 Frankfurt, Germany
| | - Sebastian E Koschade
- Goethe University Frankfurt, Institute of Biochemistry II, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany; Goethe University Frankfurt, University Hospital, Department of Medicine, Hematology/Oncology, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany
| | - Ivan Dikic
- Goethe University Frankfurt, Institute of Biochemistry II, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany
| | - Christian Münch
- Goethe University Frankfurt, Institute of Biochemistry II, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany
| | - Anja Bremm
- Goethe University Frankfurt, Institute of Biochemistry II, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany
| | - Lorenzo Brunetti
- Marche Polytechnic University, Department of Clinical and Molecular Sciences, Via Tronto 10, 60020 Ancona, Italy
| | - Christian H Brandts
- Goethe University Frankfurt, University Hospital, Department of Medicine, Hematology/Oncology, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany
| | - Hannah Uckelmann
- Goethe University Frankfurt, University Hospital, Department of Pediatrics, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany
| | - Volker Dötsch
- Goethe University Frankfurt, Institute of Biophysical Chemistry and Center for Biomolecular Magnetic Resonance, Max-von-Laue Street 9, 60438 Frankfurt, Germany
| | - Vladimir V Rogov
- Goethe University Frankfurt, Institute of Pharmaceutical Chemistry, Max-von-Laue Street 15, 60438 Frankfurt, Germany; Goethe University Frankfurt, Structural Genomics Consortium, Buchmann Institute for Molecular Life Sciences, Max-von-Laue Street 15, 60438 Frankfurt, Germany
| | - Ramachandra M Bhaskara
- Goethe University Frankfurt, Institute of Biochemistry II, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany; Goethe University Frankfurt, Buchmann Institute for Molecular Life Sciences, Max-von-Laue Street 15, 60438 Frankfurt, Germany.
| | - Stefan Müller
- Goethe University Frankfurt, Institute of Biochemistry II, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany.
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2
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Applebaum N, Chemel S, Matveev S, Pal SS, Sengupta A, Lucas B, Vigodner M. Phosphoproteome analysis of the crosstalk between sumoylation and phosphorylation in mouse spermatocytes. Biochem Biophys Res Commun 2023; 681:194-199. [PMID: 37783117 PMCID: PMC10623373 DOI: 10.1016/j.bbrc.2023.09.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 09/13/2023] [Indexed: 10/04/2023]
Abstract
Spermatogenesis is supported by various posttranslational modifications. There is growing evidence supporting a crosstalk between sumoylation and phosphorylation in different cell types. We have recently shown that inhibition of global sumoylation with a sumoylation inhibitor (Ginkgolic acid, GA) arrested purified mouse spermatocytes in vitro; the spermatocytes could not condense chromatin and disassemble the synaptonemal complex. Our data have also revealed that some kinases regulating the meiotic prophase (PLK1 and AURKB) were inhibited upon the inhibition of sumoylation. Nevertheless, specific phosphorylated targets affected by the inhibition of sumoylation have not been identified. To address this gap, in this study, we performed a comparative phospho-proteome analysis of the control spermatocytes and spermatocytes treated with the GA. Our analysis has narrowed down to several proteins implicated in the regulation of cell cycle and/or meiosis. Two of these targets, NPM1 and hnRNPH1, were studied further using western blotting in both cell lines and primary cells. Decrease in sumoylaion-dependend phosphorylation of NPM1 on Ser125 regulated by AURKB can be a contributing factor to the inability of spermatocytes to condense chromatin by the end of the prophase and should be studied further.
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Affiliation(s)
- Noa Applebaum
- Department of Biology, Stern College, Yeshiva University, New York, NY, 10016, USA
| | - Sara Chemel
- Department of Biology, Stern College, Yeshiva University, New York, NY, 10016, USA
| | - Shaina Matveev
- Department of Biology, Stern College, Yeshiva University, New York, NY, 10016, USA
| | - Sayanto Subrato Pal
- Department of Biology, Stern College, Yeshiva University, New York, NY, 10016, USA; Biotechnology Management and Entrepreneurship Program, Katz School of Science and Health, Yeshiva University, New York, NY, 10016, USA
| | - Amitabha Sengupta
- Department of Biology, Stern College, Yeshiva University, New York, NY, 10016, USA
| | - Benjamin Lucas
- Department of Biology, Stern College, Yeshiva University, New York, NY, 10016, USA
| | - Margarita Vigodner
- Department of Biology, Stern College, Yeshiva University, New York, NY, 10016, USA; Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA.
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Okuwaki M, Ozawa SI, Ebine S, Juichi M, Umeki T, Niioka K, Kikuchi T, Tanaka N. The stability of NPM1 oligomers regulated by acidic disordered regions controls the quality of liquid droplets. J Biochem 2023; 174:461-476. [PMID: 37540843 DOI: 10.1093/jb/mvad061] [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: 06/30/2023] [Revised: 07/24/2023] [Accepted: 08/01/2023] [Indexed: 08/06/2023] Open
Abstract
The nucleolus is a membrane-less nuclear body that typically forms through the process of liquid-liquid phase separation (LLPS) involving its components. NPM1 drives LLPS within the nucleolus and its oligomer formation and inter-oligomer interactions play a cooperative role in inducing LLPS. However, the molecular mechanism underlaying the regulation of liquid droplet quality formed by NPM1 remains poorly understood. In this study, we demonstrate that the N-terminal and central acidic residues within the intrinsically disordered regions (IDR) of NPM1 contribute to attenuating oligomer stability, although differences in the oligomer stability were observed only under stringent conditions. Furthermore, the impact of the IDRs is augmented by an increase in net negative charges resulting from phosphorylation within the IDRs. Significantly, we observed an increase in fluidity of liquid droplets formed by NPM1 with decreased oligomer stability. These results indicate that the difference in oligomer stability only observed biochemically under stringent conditions has a significant impact on liquid droplet quality formed by NPM1. Our findings provide new mechanistic insights into the regulation of nucleolar dynamics during the cell cycle.
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Affiliation(s)
- Mitsuru Okuwaki
- Laboratory of Biochemistry, School of Pharmacy, Kitasato University, 5-9-1, Shirokane, Minato-Ku, 108-8641 Tokyo, Japan
| | - Shin-Ichiro Ozawa
- Laboratory of Physical Chemistry for Drug Design, School of Pharmacy, Kitasato University, 5-9-1, Shirokane, Minato-Ku, 108-8641 Tokyo, Japan
| | - Shuhei Ebine
- Laboratory of Biochemistry, School of Pharmacy, Kitasato University, 5-9-1, Shirokane, Minato-Ku, 108-8641 Tokyo, Japan
| | - Motoki Juichi
- Laboratory of Biochemistry, School of Pharmacy, Kitasato University, 5-9-1, Shirokane, Minato-Ku, 108-8641 Tokyo, Japan
| | - Tadanobu Umeki
- Laboratory of Biochemistry, School of Pharmacy, Kitasato University, 5-9-1, Shirokane, Minato-Ku, 108-8641 Tokyo, Japan
| | - Kazuki Niioka
- Laboratory of Biochemistry, School of Pharmacy, Kitasato University, 5-9-1, Shirokane, Minato-Ku, 108-8641 Tokyo, Japan
| | - Taiyo Kikuchi
- Laboratory of Biochemistry, School of Pharmacy, Kitasato University, 5-9-1, Shirokane, Minato-Ku, 108-8641 Tokyo, Japan
| | - Nobutada Tanaka
- Laboratory of Physical Chemistry for Drug Design, School of Pharmacy, Kitasato University, 5-9-1, Shirokane, Minato-Ku, 108-8641 Tokyo, Japan
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Wolfová K, Otevřelová P, Holoubek A, Brodská B. Nucleolar phosphoprotein modifications as a marker of apoptosis induced by RITA treatment. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2023; 1870:119501. [PMID: 37276927 DOI: 10.1016/j.bbamcr.2023.119501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 05/19/2023] [Accepted: 05/21/2023] [Indexed: 06/07/2023]
Abstract
Reactivating p53 and Inducing Tumor Apoptosis (RITA) has been reported to increase the p53 activity and to trigger p53-dependent apoptosis in cancer cells with wild-type p53. Tumor suppressor p53 interacts with nucleolar phosphoproteins nucleophosmin (NPM) and nucleolin (NCL), which have crucial role in many cellular processes. Specific NPM mutations associated with acute myeloid leukemia (AML) cause aberrant localization of NPM and p53 in the cytoplasm with possible impact on the p53 function. We tested an effect of RITA on primary cells, and we found significant RITA-induced changes in NPM and NCL phosphorylation associated with apoptosis in cells of AML patients, but not that of healthy donors. Subsequent screening of several AML cell lines revealed heterogeneous response to RITA, and confirmed an association of the specific phosphorylation with apoptosis. While decreased NCL phosphorylation at Threonines T76 and T84 could be attributed to RITA-induced cell cycle arrest, enhanced NPM phosphorylation at Threonine T199 was not accompanied by the cell cycle changes and it correlated with sensitivity to RITA. Simultaneously, inverse changes occurred at Serine S4 of the NPM. These new findings of RITA mechanism of action could establish the NPM pT199/pS4 ratio as a marker for suitability of RITA treatment of AML cells.
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Affiliation(s)
- Kateřina Wolfová
- Department of Proteomics, Institute of Hematology and Blood Transfusion, U Nemocnice 1, 12820 Prague 2, Czech Republic
| | - Petra Otevřelová
- Department of Proteomics, Institute of Hematology and Blood Transfusion, U Nemocnice 1, 12820 Prague 2, Czech Republic
| | - Aleš Holoubek
- Department of Proteomics, Institute of Hematology and Blood Transfusion, U Nemocnice 1, 12820 Prague 2, Czech Republic
| | - Barbora Brodská
- Department of Proteomics, Institute of Hematology and Blood Transfusion, U Nemocnice 1, 12820 Prague 2, Czech Republic.
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Abstract
Centrosome amplification is a feature of multiple tumour types and has been postulated to contribute to both tumour initiation and tumour progression. This chapter focuses on the mechanisms by which an increase in centrosome number might lead to an increase or decrease in tumour progression and the role of proteins that regulate centrosome number in driving tumorigenesis.
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Affiliation(s)
- Arunabha Bose
- KS215, Advanced Centre for Treatment Research and Education in Cancer (ACTREC), Tata Memorial Centre, Navi Mumbai, Maharashtra, India
- Homi Bhabha National Institute, Mumbai, Maharashtra, India
| | - Sorab N Dalal
- KS215, Advanced Centre for Treatment Research and Education in Cancer (ACTREC), Tata Memorial Centre, Navi Mumbai, Maharashtra, India.
- Homi Bhabha National Institute, Mumbai, Maharashtra, India.
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Wiesmann N, Gieringer R, Grus F, Brieger J. Phosphoproteome Profiling Reveals Multifunctional Protein NPM1 as part of the Irradiation Response of Tumor Cells. Transl Oncol 2018; 12:308-319. [PMID: 30453269 PMCID: PMC6240713 DOI: 10.1016/j.tranon.2018.10.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 10/26/2018] [Accepted: 10/26/2018] [Indexed: 12/27/2022] Open
Abstract
To fight resistances to radiotherapy, the understanding of escape mechanisms of tumor cells is crucial. The aim of this study was to identify phosphoproteins that are regulated upon irradiation. The comparative analysis of the phosphoproteome before and after irradiation brought nucleophosmin (NPM1) into focus as a versatile phosphoprotein that has already been associated with tumorigenesis. We could show that knockdown of NPM1 significantly reduces tumor cell survival after irradiation. NPM1 is dephosphorylated stepwise within 1 hour after irradiation at two of its major phosphorylation sites: threonine-199 and threonine-234/237. This dephosphorylation is not the result of a fast cell cycle arrest, and we found a heterogenous intracellular distribution of NPM1 between the nucleoli, the nucleoplasm, and the cytoplasm after irradiation. We hypothesize that the dephosphorylation of NPM1 at threonine-199 and threonine-234/237 is part of the immediate response to irradiation and of importance for tumor cell survival. These findings could make NPM1 an attractive pharmaceutical target to radiosensitize tumor cells and improve the outcome of radiotherapy by inhibiting the pathways that help tumor cells to escape cell death after gamma irradiation.
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Affiliation(s)
- Nadine Wiesmann
- Molecular Tumor Biology, Department of Otorhinolaryngology, Head and Neck Surgery, University Medical Centre of the Johannes Gutenberg University, Langenbeckstraße 1, 55131 Mainz, Germany
| | - Rita Gieringer
- Molecular Tumor Biology, Department of Otorhinolaryngology, Head and Neck Surgery, University Medical Centre of the Johannes Gutenberg University, Langenbeckstraße 1, 55131 Mainz, Germany
| | - Franz Grus
- Experimental Ophthalmology, Department of Ophthalmology, University Medical Center of the Johannes Gutenberg University Mainz, Langenbeckstraße 1, 55131 Mainz, Germany
| | - Juergen Brieger
- Molecular Tumor Biology, Department of Otorhinolaryngology, Head and Neck Surgery, University Medical Centre of the Johannes Gutenberg University, Langenbeckstraße 1, 55131 Mainz, Germany.
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7
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Adam K, Cartel M, Lambert M, David L, Yuan L, Besson A, Mayeux P, Manenti S, Didier C. A PIM-CHK1 signaling pathway regulates PLK1 phosphorylation and function during mitosis. J Cell Sci 2018; 131:jcs213116. [PMID: 29976560 DOI: 10.1242/jcs.213116] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 06/15/2018] [Indexed: 11/20/2022] Open
Abstract
Although the kinase CHK1 is a key player in the DNA damage response (DDR), several studies have recently provided evidence of DDR-independent roles of CHK1, in particular following phosphorylation of its S280 residue. Here, we demonstrate that CHK1 S280 phosphorylation is cell cycle-dependent and peaks during mitosis. We found that this phosphorylation was catalyzed by the kinase PIM2, whose protein expression was also increased during mitosis. Importantly, we identified polo-like kinase 1 (PLK1) as a direct target of CHK1 during mitosis. Genetic or pharmacological inhibition of CHK1 reduced the activating phosphorylation of PLK1 on T210, and recombinant CHK1 was able to phosphorylate T210 of PLK1 in vitro Accordingly, S280-phosphorylated CHK1 and PLK1 exhibited similar specific mitotic localizations, and PLK1 was co-immunoprecipitated with S280-phosphorylated CHK1 from mitotic cell extracts. Moreover, CHK1-mediated phosphorylation of PLK1 was dependent on S280 phosphorylation by PIM2. Inhibition of PIM proteins reduced cell proliferation and mitotic entry, which was rescued by expressing a T210D phosphomimetic mutant of PLK1. Altogether, these data identify a new PIM-CHK1-PLK1 phosphorylation cascade that regulates different mitotic steps independently of the CHK1 DDR function.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Kévin Adam
- Institut Cochin, INSERM U1016, CNRS UMR 8104, Université Paris Descartes, 75014 Paris, France
- Ligue Nationale Contre le Cancer, équipe labellisée
| | - Maëlle Cartel
- Ligue Nationale Contre le Cancer, équipe labellisée
- Cancer Research Center of Toulouse, INSERM U1037, CNRS ERL 5294, Université de Toulouse, 31100 Toulouse, France
| | - Mireille Lambert
- Institut Cochin, INSERM U1016, CNRS UMR 8104, Université Paris Descartes, 75014 Paris, France
- Ligue Nationale Contre le Cancer, équipe labellisée
| | - Laure David
- Ligue Nationale Contre le Cancer, équipe labellisée
- Cancer Research Center of Toulouse, INSERM U1037, CNRS ERL 5294, Université de Toulouse, 31100 Toulouse, France
| | - Lingli Yuan
- Department of Hematology, The Second Xiangya Hospital, Central South University, No.139 Renmin Middle Road, Furong, Changsha, Hunan 410011, China
| | - Arnaud Besson
- Cancer Research Center of Toulouse, INSERM U1037, CNRS ERL 5294, Université de Toulouse, 31100 Toulouse, France
| | - Patrick Mayeux
- Institut Cochin, INSERM U1016, CNRS UMR 8104, Université Paris Descartes, 75014 Paris, France
- Ligue Nationale Contre le Cancer, équipe labellisée
| | - Stéphane Manenti
- Ligue Nationale Contre le Cancer, équipe labellisée
- Cancer Research Center of Toulouse, INSERM U1037, CNRS ERL 5294, Université de Toulouse, 31100 Toulouse, France
| | - Christine Didier
- Ligue Nationale Contre le Cancer, équipe labellisée
- Cancer Research Center of Toulouse, INSERM U1037, CNRS ERL 5294, Université de Toulouse, 31100 Toulouse, France
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Kunchala P, Kuravi S, Jensen R, McGuirk J, Balusu R. When the good go bad: Mutant NPM1 in acute myeloid leukemia. Blood Rev 2018; 32:167-183. [DOI: 10.1016/j.blre.2017.11.001] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 10/19/2017] [Accepted: 11/02/2017] [Indexed: 12/26/2022]
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9
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Kumar S, Sharma G, Chakraborty C, Sharma AR, Kim J. Regulatory functional territory of PLK-1 and their substrates beyond mitosis. Oncotarget 2017; 8:37942-37962. [PMID: 28415805 PMCID: PMC5514964 DOI: 10.18632/oncotarget.16290] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Accepted: 03/03/2017] [Indexed: 12/04/2022] Open
Abstract
Polo-like kinase 1 (PLK-1) is a well-known (Ser/Thr) mitotic protein kinase and is considered as a proto-oncogene. As hyper-activation of PLK-1 is broadly associated with poor prognosis and cancer progression, it is one of the most extensively studied mitotic kinases. During mitosis, PLK-1 regulates various cell cycle events, such as spindle pole maturation, chromosome segregation and cytokinesis. However, studies have demonstrated that the role of PLK-1 is not only restricted to mitosis, but PLK-1 can also regulate other vital events beyond mitosis, including transcription, translation, ciliogenesis, checkpoint adaptation and recovery, apoptosis, chromosomes dynamics etc. Recent reviews have tried to define the regulatory role of PLK-1 during mitosis progression and tumorigenesis, but its' functional role beyond mitosis is still largely unexplored. PLK-1 can regulate the activity of many proteins that work outside of its conventional territory. The dysregulation of these proteins can cause diseases such as Alzheimer's disease, tumorigenesis etc. and may also lead to drug resistance. Thus, in this review, we discussed the versatile role of PLK-1 and tried to collect data to validate its' functional role in cell cycle regulation apart from mitosis.
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Affiliation(s)
- Shiv Kumar
- Department of Biochemistry, Institute of Cell Differentiation and Aging, Hallym University, College of Medicine, Chucheonsi, Gangwondo, Republic of Korea
| | - Garima Sharma
- Institute For Skeletal Aging & Orthopedic Surgery, Hallym University, College of Medicine, Chucheonsi, Gangwondo, Republic of Korea
| | - Chiranjib Chakraborty
- Department of Bio-informatics, School of Computer and Information Sciences, Galgotias University, Greater Noida, Uttar Pradesh, India
| | - Ashish Ranjan Sharma
- Institute For Skeletal Aging & Orthopedic Surgery, Hallym University, College of Medicine, Chucheonsi, Gangwondo, Republic of Korea
| | - Jaebong Kim
- Department of Biochemistry, Institute of Cell Differentiation and Aging, Hallym University, College of Medicine, Chucheonsi, Gangwondo, Republic of Korea
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10
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Lin J, Hisaoka M, Nagata K, Okuwaki M. Functional characterization and efficient detection of Nucleophosmin/NPM1 oligomers. Biochem Biophys Res Commun 2016; 480:702-708. [PMID: 27983985 DOI: 10.1016/j.bbrc.2016.10.125] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 10/27/2016] [Indexed: 11/16/2022]
Abstract
NPM1/nucleophosmin is a multifunctional and oligomeric phosphoprotein. A number of observations have suggested that changes in the oligomer formation of NPM1 could influence its biological functions, especially its oncogenic functions. To understand the functional meaning of oligomerization of NPM1/nucleophosmin, we have established a novel method to monitor protein oligomerization in cells. We utilized the split synthetic Renilla luciferase protein fragment-assisted complementation (SRL-PFAC) bioluminescence activity and observed the change of NPM1 oligomer levels under various cell culture conditions. Our study provides a method for systematic characterization of NPM1 oligomer formation changes and for screening inhibitors of NPM1 oligomerization.
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Affiliation(s)
- Jianhuang Lin
- PhD Program in Human Biology, School of Integrative and Global Majors, University of Tsukuba, 1-1-1, Tennodai, Tsukuba, 305-8575, Japan; Department of Infection Biology, Faculty of Medicine, University of Tsukuba, 1-1-1, Tennodai, Tsukuba, 305-8575, Japan
| | - Miharu Hisaoka
- Department of Infection Biology, Faculty of Medicine, University of Tsukuba, 1-1-1, Tennodai, Tsukuba, 305-8575, Japan
| | - Kyosuke Nagata
- Department of Infection Biology, Faculty of Medicine, University of Tsukuba, 1-1-1, Tennodai, Tsukuba, 305-8575, Japan
| | - Mitsuru Okuwaki
- PhD Program in Human Biology, School of Integrative and Global Majors, University of Tsukuba, 1-1-1, Tennodai, Tsukuba, 305-8575, Japan; Department of Infection Biology, Faculty of Medicine, University of Tsukuba, 1-1-1, Tennodai, Tsukuba, 305-8575, Japan.
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11
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Kozakai Y, Kamada R, Furuta J, Kiyota Y, Chuman Y, Sakaguchi K. PPM1D controls nucleolar formation by up-regulating phosphorylation of nucleophosmin. Sci Rep 2016; 6:33272. [PMID: 27619510 PMCID: PMC5020408 DOI: 10.1038/srep33272] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 08/24/2016] [Indexed: 01/01/2023] Open
Abstract
An increase of nucleolar number and size has made nucleoli essential markers for cytology and tumour development. However, the underlying basis for their structural integrity and abundance remains unclear. Protein phosphatase PPM1D was found to be up-regulated in different carcinomas including breast cancers. Here, we demonstrate for the first time that PPM1D regulates nucleolar formation via inducing an increased phosphorylation of the nucleolar protein NPM. We show that PPM1D overexpression induces an increase in the nucleolar number regardless of p53 status. We also demonstrated that specific sequential phosphorylation of NPM is important for nucleolar formation and that PPM1D is a novel upstream regulator of this phosphorylation pathway. These results enhance our understanding of the molecular mechanisms that govern nucleoli formation by demonstrating that PPM1D regulates nucleolar formation by regulating NPM phosphorylation status through a novel signalling pathway, PPM1D-CDC25C-CDK1-PLK1.
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Affiliation(s)
- Yuuki Kozakai
- Laboratory of Biological Chemistry, Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo, Japan
| | - Rui Kamada
- Laboratory of Biological Chemistry, Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo, Japan
| | - Junya Furuta
- Laboratory of Biological Chemistry, Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo, Japan
| | - Yuhei Kiyota
- Laboratory of Biological Chemistry, Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo, Japan
| | - Yoshiro Chuman
- Laboratory of Biological Chemistry, Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo, Japan
| | - Kazuyasu Sakaguchi
- Laboratory of Biological Chemistry, Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo, Japan
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12
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Helmke C, Becker S, Strebhardt K. The role of Plk3 in oncogenesis. Oncogene 2016; 35:135-47. [PMID: 25915845 DOI: 10.1038/onc.2015.105] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Revised: 02/02/2015] [Accepted: 02/02/2015] [Indexed: 01/08/2023]
Abstract
The polo-like kinases (Plks) encompass a family of five serine/threonine protein kinases that play essential roles in many cellular processes involved in the control of the cell cycle, including entry into mitosis, DNA replication and the response to different types of stress. Plk1, which has been validated as a cancer target, came into the focus of many pharmaceutical companies for the development of small-molecule inhibitors as anticancer agents. Recently, FDA (Food and Drug Administration) has granted a breakthrough therapy designation to the Plk inhibitor BI 6727 (volasertib), which provided a survival benefit for patients suffering from acute myeloid leukemia. However, the various ATP-competitive inhibitors of Plk1 that are currently in clinical development also inhibit the activities of Plk2 and Plk3, which are considered as tumor suppressors. Plk3 contributes to the control and progression of the cell cycle while acting as a mediator of apoptosis and various types of cellular stress. The aberrant expression of Plk3 was found in different types of tumors. Recent progress has improved our understanding of Plk3 in regulating stress signaling and tumorigenesis. When using ATP-competitive Plk1 inhibitors, the biological roles of Plk1-related family members like Plk3 in cancer cells need to be considered carefully to improve treatment strategies against cancer.
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Affiliation(s)
- C Helmke
- Department of Obstetrics and Gynecology, School of Medicine, J.W. Goethe University, Frankfurt, Germany
| | - S Becker
- Department of Obstetrics and Gynecology, School of Medicine, J.W. Goethe University, Frankfurt, Germany
| | - K Strebhardt
- Department of Obstetrics and Gynecology, School of Medicine, J.W. Goethe University, Frankfurt, Germany
- German Cancer Consortium (DKTK), Heidelberg, Germany
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13
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Asteriti IA, De Mattia F, Guarguaglini G. Cross-Talk between AURKA and Plk1 in Mitotic Entry and Spindle Assembly. Front Oncol 2015; 5:283. [PMID: 26779436 PMCID: PMC4688340 DOI: 10.3389/fonc.2015.00283] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 11/30/2015] [Indexed: 12/21/2022] Open
Abstract
The Aurora kinase A (AURKA) is involved in different aspects of mitotic control, from mitotic entry to cytokinesis. Consistent with its pleiotropic roles, several AURKA interactors are able to modulate its activity, the best characterized being the microtubule-binding protein TPX2, the centrosomal protein Cep192, and Bora. Bora has been described as an essential cofactor of AURKA for phosphorylation-mediated activation of the mitotic kinase polo-like kinase 1 (Plk1) at the G2/M transition. A complex AURKA/Plk1 signaling axis is emerging, with multiple involved actors; recent data suggest that this control network is not restricted to mitotic entry only, but operates throughout mitosis. Here, we integrate available data from the literature to depict the complex interplay between AURKA and Plk1 in G2 and mitosis and how it contributes to their mitotic functions. We will particularly focus on how the activity of specifically localized AURKA/Plk1 pools is modulated in time and space by their reciprocal regulation to ensure the timely and coordinated unfolding of downstream mitotic events.
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Affiliation(s)
- Italia Anna Asteriti
- Institute of Molecular Biology and Pathology, National Research Council (CNR), c/o Department of Biology and Biotechnology, Sapienza University of Rome , Rome , Italy
| | - Fabiola De Mattia
- Institute of Molecular Biology and Pathology, National Research Council (CNR), c/o Department of Biology and Biotechnology, Sapienza University of Rome , Rome , Italy
| | - Giulia Guarguaglini
- Institute of Molecular Biology and Pathology, National Research Council (CNR), c/o Department of Biology and Biotechnology, Sapienza University of Rome , Rome , Italy
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14
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Kim JJ, Gil NY, Zhang XH, Chun KH, Fang G, Kim J, Cho H, Jang CY, Cha HJ. Sirt1 Regulates Microtubule Dynamics Through Negative Regulation of Plk1 in Mitosis. J Cell Biochem 2015; 116:1888-97. [PMID: 25737075 DOI: 10.1002/jcb.25144] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 02/17/2015] [Indexed: 02/01/2023]
Abstract
Although loss of Sirt1 leads to chromosome aneuploidy, which accounts for higher tumor susceptibility, the molecular mechanisms remain unclear. Herein, we demonstrate that Sirt1 directly regulates Plk1, of which activity is critical for mitotic progression and spindle dynamics. Depletion or inhibition of Sirt1 significantly perturbs the formation of the mitotic spindle, leading to defective chromosome segregation. Elevated depolymerization of the mitotic spindle following loss of Sirt1 was associated with the deregulation of Plk1 activity. Thus, we conclude that Sirt1 may contribute to a mitotic regulator that controls spindle dynamics through Plk1 activity, resulting in fine-tuning of Plk1 dependent microtubule dynamics.
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Affiliation(s)
- Jin-Ju Kim
- College of Natural Sciences, Department of Life Sciences, Sogang University, Seoul, 121-742, Republic of Korea
| | - Na-Yeon Gil
- College of Natural Sciences, Department of Life Sciences, Sogang University, Seoul, 121-742, Republic of Korea
| | - Xiang Hua Zhang
- Research Center for Cell Fate Control, College of Pharmacy, Sookmyung Women's University, Seoul, 140-742, Republic of Korea
| | - Kwang-Hoon Chun
- Gachon Institute of Pharmaceutical Sciences, College of Pharmacy, Gachon University, Inchoen, Republic of Korea
| | - Guowei Fang
- Genentech, Inc., South San Francisco, California, 94080
| | - Joon Kim
- Laboratory of Biochemistry, School of Life Sciences & Biotechnology, Korea University, Seoul, 136-701, Republic of Korea
| | - Hyeseong Cho
- Department of Biochemistry, Ajou University School of Medicine, Suwon, Republic of Korea
| | - Chang-Young Jang
- Research Center for Cell Fate Control, College of Pharmacy, Sookmyung Women's University, Seoul, 140-742, Republic of Korea
| | - Hyuk-Jin Cha
- College of Natural Sciences, Department of Life Sciences, Sogang University, Seoul, 121-742, Republic of Korea
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15
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Guo C, Al-Jamal WT, Toma FM, Bianco A, Prato M, Al-Jamal KT, Kostarelos K. Design of Cationic Multiwalled Carbon Nanotubes as Efficient siRNA Vectors for Lung Cancer Xenograft Eradication. Bioconjug Chem 2015; 26:1370-9. [PMID: 26036843 DOI: 10.1021/acs.bioconjchem.5b00249] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Polo-Like Kinase (PLK1) has been identified as a potential target in cancer gene therapy via chemical or genetic inhibitory approaches. The biomedical applications of chemically functionalized carbon nanotubes (f-CNTs) in cancer therapy have been studied due to their ability to efficiently deliver siRNA intracellularly. In this study, we established the capacity of cationic MWNT-NH3(+) to deliver the apoptotic siRNA against PLK1 (siPLK1) in Calu6 tumor xenografts by direct intratumoral injections. A direct comparison with cationic liposomes was made. This study validates the PLK1 gene as a potential target in cancer gene therapy including lung cancer, as demonstrated by the therapeutic efficacy of siPLK1:MWNT-NH3(+) complexes and their ability to significantly improve animal survival. Biological analysis of the siPLK1:MWNT-NH3(+) treated tumors by qRT-PCR and Western blot, in addition to TUNEL staining confirmed the biological functionality of the siRNA intratumorally, suggesting that tumor eradication was due to PLK1 knockdown. Furthermore, by using a fluorescently labeled, noncoding siRNA sequence complexed with MWNT-NH3(+), we established for the first time that the improved therapeutic efficacy observed in f-CNT-based siRNA delivery is directly proportional to the enhanced siRNA retention in the solid tumor and subsequent uptake by tumor cells after local administration in vivo.
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Affiliation(s)
- Chang Guo
- †Nanomedicine Lab, UCL School of Pharmacy, Faculty of Life Sciences, University College London, London WC1N 1AX, United Kingdom
| | - Wafa T Al-Jamal
- †Nanomedicine Lab, UCL School of Pharmacy, Faculty of Life Sciences, University College London, London WC1N 1AX, United Kingdom
| | - Francesca M Toma
- ‡Center of Excellence for Nanostructured Materials, Department of Chemical and Pharmaceutical Sciences, University of Trieste, 34127 Trieste, Italy
| | - Alberto Bianco
- §CNRS, Institut de Biologie Moléculaire et Cellulaire, UPR 3572, Immunopathologie et Chimie Thérapeutique, 67000 Strasbourg, France
| | - Maurizio Prato
- ‡Center of Excellence for Nanostructured Materials, Department of Chemical and Pharmaceutical Sciences, University of Trieste, 34127 Trieste, Italy
| | - Khuloud T Al-Jamal
- †Nanomedicine Lab, UCL School of Pharmacy, Faculty of Life Sciences, University College London, London WC1N 1AX, United Kingdom
| | - Kostas Kostarelos
- †Nanomedicine Lab, UCL School of Pharmacy, Faculty of Life Sciences, University College London, London WC1N 1AX, United Kingdom
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16
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Jeong HC, Gil NY, Lee HS, Cho SJ, Kim K, Chun KH, Cho H, Cha HJ. Timely Degradation of Wip1 Phosphatase by APC/C Activator Protein Cdh1 is Necessary for Normal Mitotic Progression. J Cell Biochem 2015; 116:1602-12. [DOI: 10.1002/jcb.25114] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Accepted: 01/23/2015] [Indexed: 12/16/2022]
Affiliation(s)
- Ho-Chang Jeong
- College of Natural Sciences; Department of Life Sciences; Sogang University; Seoul Korea
| | - Na-Yeon Gil
- College of Natural Sciences; Department of Life Sciences; Sogang University; Seoul Korea
| | - Ho-Soo Lee
- Department of Biochemistry; Ajou University School of Medicine; Suwon Korea
- Genomic Instability Research Center; Ajou University School of Medicine; Suwon Korea
| | - Seung-Ju Cho
- College of Natural Sciences; Department of Life Sciences; Sogang University; Seoul Korea
| | - Kyungtae Kim
- National Cancer Center; Goyang-si; Gyeonggi-do Korea
| | - Kwang-Hoon Chun
- Gachon Institute of Pharmaceutical Sciences; College of Pharmacy; Gachon University; Incheon Korea
| | - Hyeseong Cho
- Department of Biochemistry; Ajou University School of Medicine; Suwon Korea
- Genomic Instability Research Center; Ajou University School of Medicine; Suwon Korea
| | - Hyuk-Jin Cha
- College of Natural Sciences; Department of Life Sciences; Sogang University; Seoul Korea
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17
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Pfister JA, D'Mello SR. Insights into the regulation of neuronal viability by nucleophosmin/B23. Exp Biol Med (Maywood) 2015; 240:774-86. [PMID: 25908633 DOI: 10.1177/1535370215579168] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The vastness of the neuronal network that constitutes the human brain proves challenging when trying to understand its complexity. Furthermore, due to the senescent state they enter into upon maturation, neurons lack the ability to regenerate in the face of insult, injury or death. Consequently, their excessive death can be detrimental to the proper functioning of the brain. Therefore, elucidating the mechanisms regulating neuronal survival is, while challenging, of great importance as the incidence of neurological disease is becoming more prevalent in today's society. Nucleophosmin/B23 (NPM) is an abundant and ubiquitously expressed protein that regulates vital cellular processes such as ribosome biogenesis, cell proliferation and genomic stability. As a result, it is necessary for proper embryonic development, but has also been implicated in many cancers. While highly studied in the context of proliferative cells, there is a lack of understanding NPM's role in post-mitotic neurons. By exploring its role in healthy neurons as well as its function in the regulation of cell death and neurodegeneration, there can be a better understanding of how these diseases initiate and progress. Owing to what is thus far known about its function in the cell, NPM could be an attractive therapeutic target in the treatment of neurodegenerative diseases.
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Affiliation(s)
- Jason A Pfister
- Department of Biological Sciences, University of Texas at Dallas, Richardson, TX 75080, USA Department of Biological Sciences, Southern Methodist University, Dallas, TX 75275, USA
| | - Santosh R D'Mello
- Department of Biological Sciences, Southern Methodist University, Dallas, TX 75275, USA
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18
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Perera Y, Pedroso S, Borras-Hidalgo O, Vázquez DM, Miranda J, Villareal A, Falcón V, Cruz LD, Farinas HG, Perea SE. Pharmacologic inhibition of the CK2-mediated phosphorylation of B23/NPM in cancer cells selectively modulates genes related to protein synthesis, energetic metabolism, and ribosomal biogenesis. Mol Cell Biochem 2015; 404:103-12. [DOI: 10.1007/s11010-015-2370-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 02/23/2015] [Indexed: 11/29/2022]
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19
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Dynamic conformations of nucleophosmin (NPM1) at a key monomer-monomer interface affect oligomer stability and interactions with granzyme B. PLoS One 2014; 9:e115062. [PMID: 25490769 PMCID: PMC4260957 DOI: 10.1371/journal.pone.0115062] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 11/05/2014] [Indexed: 01/02/2023] Open
Abstract
Nucleophosmin (NPM1) is an abundant, nucleolar tumor antigen with important roles in cell proliferation and putative contributions to oncogenesis. Wild-type NPM1 forms pentameric oligomers through interactions at the amino-terminal core domain. A truncated form of NPM1 found in some hepatocellular carcinoma tissue formed an unusually stable oligomer and showed increased susceptibility to cleavage by granzyme B. Initiation of translation at the seventh methionine generated a protein (M7-NPM) that shared all these properties. We used deuterium exchange mass spectrometry (DXMS) to perform a detailed structural analysis of wild-type NPM1 and M7-NPM, and found dynamic conformational shifts or local “unfolding” at a specific monomer-monomer interface which included the β-hairpin “latch.” We tested the importance of interactions at the β-hairpin “latch” by replacing a conserved tyrosine in the middle of the β-hairpin loop with glutamic acid, generating Y67E-NPM. Y67E-NPM did not form stable oligomers and further, prevented wild-type NPM1 oligomerization in a dominant-negative fashion, supporting the critical role of the β-hairpin “latch” in monomer-monomer interactions. Also, we show preferential cleavage by granzyme B at one of two available aspartates (either D161 or D122) in M7-NPM and Y67E-NPM, whereas wild-type NPM1 was cleaved at both sites. Thus, we observed a correlation between the propensity to form oligomers and granzyme B cleavage site selection in nucleophosmin proteins, suggesting that a small change at an important monomer-monomer interface can affect conformational shifts and impact protein-protein interactions.
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20
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Bucur O, Stancu AL, Muraru MS, Melet A, Petrescu SM, Khosravi-Far R. PLK1 is a binding partner and a negative regulator of FOXO3 tumor suppressor. Discoveries (Craiova) 2014; 2:e16. [PMID: 26280018 PMCID: PMC4535815 DOI: 10.15190/d.2014.8] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
FOXO family members (FOXOs: FOXO1, FOXO3, FOXO4 and FOXO6) are important transcription factors and tumor suppressors controlling cell homeostasis and cell fate. They are characterized by an extraordinary functional diversity, being involved in regulation of cell cycle, proliferation, apoptosis, DNA damage response, oxidative detoxification, cell differentiation and stem cell maintenance, cell metabolism, angiogenesis, cardiac and other organ's development, aging, and other critical cellular processes. FOXOs are tightly regulated by reversible phosphorylation, ubiquitination, acetylation and methylation. Interestingly, the known kinases phosphorylate only a small percentage of the known or predicted FOXOs phosphorylation sites, suggesting that additional kinases that phosphorylate and control FOXOs activity exist. In order to identify novel regulators of FOXO3, we have employed a proteomics screening strategy. Using HeLa cancer cell line and a Tandem Affinity Purification followed by Mass Spectrometry analysis, we identified several proteins as binding partners of FOXO3. Noteworthy, Polo Like Kinase 1 (PLK1) proto-oncogene was one of the identified FOXO3 binding partners. PLK1 plays a critical role during cell cycle (G2-M transition and all phases of mitosis) and in maintenance of genomic stability. Our experimental results presented in this manuscript demonstrate that FOXO3 and PLK1 exist in a molecular complex through most of the phases of the cell cycle, with a higher occurrence in the G2-M cell cycle phases. PLK1 induces translocation of FOXO3 from the nucleus to the cytoplasm and suppresses FOXO3 activity, measured by the decrease in the pro-apoptotic Bim protein levels and in the cell cycle inhibitor protein p27. Furthermore, PLK1 can directly phosphorylate FOXO3 in an in vitro kinase assay. These results present the discovery of PLK1 proto-oncogene as a binding partner and a negative regulator of FOXO3 tumor suppressor.
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Affiliation(s)
- Octavian Bucur
- Department of Pathology, Harvard Medical School and Beth Israel Deaconess Medical Center, Boston, MA, USA
- Institute of Biochemistry of the Romanian Academy, Bucharest, Romania
| | - Andreea Lucia Stancu
- Department of Pathology, Harvard Medical School and Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - Maria Sinziana Muraru
- Department of Pathology, Harvard Medical School and Beth Israel Deaconess Medical Center, Boston, MA, USA
| | | | | | - Roya Khosravi-Far
- Department of Pathology, Harvard Medical School and Beth Israel Deaconess Medical Center, Boston, MA, USA
- Biological and Biomedical Sciences Program, Harvard Medical School, Boston, MA, USA
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21
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Abstract
Polo-like kinase 1 (Plk1) is a well-established mitotic regulator with a diverse range of biologic functions continually being identified throughout the cell cycle. Preclinical evidence suggests that the molecular targeting of Plk1 could be an effective therapeutic strategy in a wide range of cancers; however, that success has yet to be translated to the clinical level. The lack of clinical success has raised the question of whether there is a true oncogenic addiction to Plk1 or if its overexpression in tumors is solely an artifact of increased cellular proliferation. In this review, we address the role of Plk1 in carcinogenesis by discussing the cell cycle and DNA damage response with respect to their associations with classic oncogenic and tumor suppressor pathways that contribute to the transcriptional regulation of Plk1. A thorough examination of the available literature suggests that Plk1 activity can be dysregulated through key transformative pathways, including both p53 and pRb. On the basis of the available literature, it may be somewhat premature to draw a definitive conclusion on the role of Plk1 in carcinogenesis. However, evidence supports the notion that oncogene dependence on Plk1 is not a late occurrence in carcinogenesis and it is likely that Plk1 plays an active role in carcinogenic transformation.
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Affiliation(s)
- Brian D. Cholewa
- Department of Dermatology, University of Wisconsin, Madison, WI
- Molecular and Environmental Toxicology Center, University of Wisconsin, Madison, WI
| | - Xiaoqi Liu
- Department of Biochemistry, Purdue University, West Lafayette, IN
| | - Nihal Ahmad
- Department of Dermatology, University of Wisconsin, Madison, WI
- Molecular and Environmental Toxicology Center, University of Wisconsin, Madison, WI
- William S. Middleton Memorial VA Hospital, Madison, WI
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22
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Pihan GA. Centrosome dysfunction contributes to chromosome instability, chromoanagenesis, and genome reprograming in cancer. Front Oncol 2013; 3:277. [PMID: 24282781 PMCID: PMC3824400 DOI: 10.3389/fonc.2013.00277] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Accepted: 10/28/2013] [Indexed: 12/19/2022] Open
Abstract
The unique ability of centrosomes to nucleate and organize microtubules makes them unrivaled conductors of important interphase processes, such as intracellular payload traffic, cell polarity, cell locomotion, and organization of the immunologic synapse. But it is in mitosis that centrosomes loom large, for they orchestrate, with clockmaker's precision, the assembly and functioning of the mitotic spindle, ensuring the equal partitioning of the replicated genome into daughter cells. Centrosome dysfunction is inextricably linked to aneuploidy and chromosome instability, both hallmarks of cancer cells. Several aspects of centrosome function in normal and cancer cells have been molecularly characterized during the last two decades, greatly enhancing our mechanistic understanding of this tiny organelle. Whether centrosome defects alone can cause cancer, remains unanswered. Until recently, the aggregate of the evidence had suggested that centrosome dysfunction, by deregulating the fidelity of chromosome segregation, promotes and accelerates the characteristic Darwinian evolution of the cancer genome enabled by increased mutational load and/or decreased DNA repair. Very recent experimental work has shown that missegregated chromosomes resulting from centrosome dysfunction may experience extensive DNA damage, suggesting additional dimensions to the role of centrosomes in cancer. Centrosome dysfunction is particularly prevalent in tumors in which the genome has undergone extensive structural rearrangements and chromosome domain reshuffling. Ongoing gene reshuffling reprograms the genome for continuous growth, survival, and evasion of the immune system. Manipulation of molecular networks controlling centrosome function may soon become a viable target for specific therapeutic intervention in cancer, particularly since normal cells, which lack centrosome alterations, may be spared the toxicity of such therapies.
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Affiliation(s)
- German A Pihan
- Department of Pathology and Laboratory Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School , Boston, MA , USA
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Ramos-Echazábal G, Chinea G, García-Fernández R, Pons T. In silico studies of potential phosphoresidues in the human nucleophosmin/B23: its kinases and related biological processes. J Cell Biochem 2012; 113:2364-74. [PMID: 22573554 DOI: 10.1002/jcb.24108] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Human nucleophosmin/B23 is a phosphoprotein involved in ribosome biogenesis, centrosome duplication, cancer, and apoptosis. Its function, localization, and mobility within cells, are highly regulated by phosphorylation events. Up to 21 phosphosites of B23 have been experimentally verified even though the corresponding kinase is known only for seven of them. In this work, we predict the phosphorylation sites in human B23 using six kinase-specific servers (KinasePhos 2.0, PredPhospho, NetPhosK 1.0, PKC Scan, pkaPS, and MetaPredPS) plus DISPHOS 1.3, which is not kinase specific. The results were integrated with information regarding 3D structure and residue conservation of B23, as well as cellular localizations, cellular processes, signaling pathways and protein-protein interaction networks involving both B23 and each predicted kinase. Thus, all 40 potential phosphosites of B23 were predicted with significant score (>0.50) as substrates of at least one of 38 kinases. Thirteen of these residues are newly proposed showing high susceptibility of phosphorylation considering their solvent accessibility. Our results also suggest that the enzymes CDKs, PKC, CK2, PLK1, and PKA could phosphorylate B23 at higher number of sites than those previously reported. Furthermore, PDK, GSK3, ATM, MAPK, PKB, and CHK1 could mediate multisite phosphorylation of B23, although they have not been verified as kinases for this protein. Finally, we suggest that B23 phosphorylation is related to cellular processes such as apoptosis, cell survival, cell proliferation, and response to DNA damage stimulus, in which these kinases are involved. These predictions could contribute to a better understanding, as well as addressing further experimental studies, of B23 phosphorylation.
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Affiliation(s)
- Gioser Ramos-Echazábal
- Department of Animal and Human Biology, Faculty of Biology, University of Havana, Havana 10400, Cuba.
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Methylated chrysin reduced cell proliferation, but antagonized cytotoxicity of other anticancer drugs in acute lymphoblastic leukemia. Anticancer Drugs 2012; 23:417-25. [PMID: 22205153 DOI: 10.1097/cad.0b013e32834fb731] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The efficacy of 5,7-dimethoxyflavone (DMF), a methylated analog of chrysin, as a therapeutic agent to treat acute lymphoblastic leukemia (ALL) was investigated. Using a panel of ALL cell lines, the IC50 (half-maximal inhibitory concentration) of DMF varied between 2.8 and 7.0 μg/ml. DMF induced G0/G1 cell cycle arrest, concomitant with a decreased expression of phosphorylated retinoblastoma-associated protein 1. DMF increased the rate of apoptosis, although it was apparent only after a long period of exposure (96 h). The accumulation of oxidative stress was not involved in the growth-inhibitory effects of DMF. As DMF reduced the intracellular levels of glutathione, the combination effects of DMF with other anticancer drugs were evaluated using the improved Isobologram and the combination index method. In the simultaneous drug combination assay, DMF antagonized the cytotoxicity of 4-hydroperoxy-cyclophosphamide, cytarabine, vincristine, and L-asparaginase in all tested ALL cells. This study demonstrated that DMF, a methylated flavone, was an effective chemotherapy agent that could inhibit cell cycle arrest and induce apoptosis in ALL cell lines. However, combination therapy with DMF and other anticancer drugs is not recommended.
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25
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So CH, Michal AM, Mashayekhi R, Benovic JL. G protein-coupled receptor kinase 5 phosphorylates nucleophosmin and regulates cell sensitivity to polo-like kinase 1 inhibition. J Biol Chem 2012; 287:17088-17099. [PMID: 22467873 PMCID: PMC3366848 DOI: 10.1074/jbc.m112.353854] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Revised: 03/27/2012] [Indexed: 01/14/2023] Open
Abstract
G protein-coupled receptor kinases (GRKs) phosphorylate activated G protein-coupled receptors, leading to their desensitization and endocytosis. GRKs have also been implicated in phosphorylating other classes of proteins and can localize in a variety of cellular compartments, including the nucleus. Here, we attempted to identify potential nuclear substrates for GRK5. Our studies reveal that GRK5 is able to interact with and phosphorylate nucleophosmin (NPM1) both in vitro and in intact cells. NPM1 is a nuclear protein that regulates a variety of cell functions including centrosomal duplication, cell cycle control, and apoptosis. GRK5 interaction with NPM1 is mediated by the N-terminal domain of each protein, and GRK5 primarily phosphorylates NPM1 at Ser-4, a site shared with polo-like kinase 1 (PLK1). NPM1 phosphorylation by GRK5 and PLK1 correlates with the sensitivity of cells to undergo apoptosis with cells having higher GRK5 levels being less sensitive and cells with lower GRK5 being more sensitive to PLK1 inhibitor-induced apoptosis. Taken together, our results demonstrate that GRK5 phosphorylates Ser-4 in nucleophosmin and regulates the sensitivity of cells to PLK1 inhibition.
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Affiliation(s)
- Christopher H So
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Allison M Michal
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Rouzbeh Mashayekhi
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Jeffrey L Benovic
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107.
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26
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Oppermann FS, Grundner-Culemann K, Kumar C, Gruss OJ, Jallepalli PV, Daub H. Combination of chemical genetics and phosphoproteomics for kinase signaling analysis enables confident identification of cellular downstream targets. Mol Cell Proteomics 2012; 11:O111.012351. [PMID: 22199227 PMCID: PMC3322579 DOI: 10.1074/mcp.o111.012351] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Revised: 11/18/2011] [Indexed: 12/20/2022] Open
Abstract
Delineation of phosphorylation-based signaling networks requires reliable data about the underlying cellular kinase-substrate interactions. We report a chemical genetics and quantitative phosphoproteomics approach that encompasses cellular kinase activation in combination with comparative replicate mass spectrometry analyses of cells expressing either inhibitor-sensitive or resistant kinase variant. We applied this workflow to Plk1 (Polo-like kinase 1) in mitotic cells and induced cellular Plk1 activity by wash-out of the bulky kinase inhibitor 3-MB-PP1, which targets a mutant kinase version with an enlarged catalytic pocket while not interfering with wild-type Plk1. We quantified more than 20,000 distinct phosphorylation sites by SILAC, approximately half of which were measured in at least two independent experiments in cells expressing mutant and wild-type Plk1. Based on replicate phosphorylation site quantifications in both mutant and wild-type Plk1 cells, our chemical genetic proteomics concept enabled stringent comparative statistics by significance analysis of microarrays, which unveiled more than 350 cellular downstream targets of Plk1 validated by full concordance of both statistical and experimental data. Our data point to hitherto poorly characterized aspects in Plk1-controlled mitotic progression and provide a largely extended resource for functional studies. We anticipate the described strategies to be of general utility for systematic and confident identification of cellular protein kinase substrates.
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Affiliation(s)
| | | | - Chanchal Kumar
- the ‖Department of Proteomics and Signal Transduction, 82152 Martinsried, Germany
| | - Oliver J. Gruss
- ‡‡DKFZ-ZMBH Alliance, Zentrum für Molekulare Biologie der Universität Heidelberg, 69120 Heidelberg, Germany, and
| | - Prasad V. Jallepalli
- the §§Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10065
| | - Henrik Daub
- From the Cell Signaling Group, ‡Department of Molecular Biology and
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27
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Eke I, Deuse Y, Hehlgans S, Gurtner K, Krause M, Baumann M, Shevchenko A, Sandfort V, Cordes N. β₁Integrin/FAK/cortactin signaling is essential for human head and neck cancer resistance to radiotherapy. J Clin Invest 2012; 122:1529-40. [PMID: 22378044 DOI: 10.1172/jci61350] [Citation(s) in RCA: 181] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2011] [Accepted: 01/18/2012] [Indexed: 02/06/2023] Open
Abstract
Integrin signaling critically contributes to the progression, growth, and therapy resistance of malignant tumors. Here, we show that targeting of β₁ integrins with inhibitory antibodies enhances the sensitivity to ionizing radiation and delays the growth of human head and neck squamous cell carcinoma cell lines in 3D cell culture and in xenografted mice. Mechanistically, dephosphorylation of focal adhesion kinase (FAK) upon inhibition of β₁ integrin resulted in dissociation of a FAK/cortactin protein complex. This, in turn, downregulated JNK signaling and induced cell rounding, leading to radiosensitization. Thus, these findings suggest that robust and selective pharmacological targeting of β₁ integrins may provide therapeutic benefit to overcome tumor cell resistance to radiotherapy.
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Affiliation(s)
- Iris Eke
- OncoRay - National Center for Radiation Research in Oncology, Medical Faculty Carl Gustav Carus, Dresden University of Technology, Dresden, Germany
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28
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Michal AM, So CH, Beeharry N, Shankar H, Mashayekhi R, Yen TJ, Benovic JL. G Protein-coupled receptor kinase 5 is localized to centrosomes and regulates cell cycle progression. J Biol Chem 2012; 287:6928-40. [PMID: 22223642 DOI: 10.1074/jbc.m111.298034] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
G protein-coupled receptor kinases (GRKs) are important regulators of G protein-coupled receptor function and mediate receptor desensitization, internalization, and signaling. While GRKs also interact with and/or phosphorylate many other proteins and modify their function, relatively little is known about the cellular localization of endogenous GRKs. Here we report that GRK5 co-localizes with γ-tubulin, centrin, and pericentrin in centrosomes. The centrosomal localization of GRK5 is observed predominantly at interphase and although its localization is not dependent on microtubules, it can mediate microtubule nucleation of centrosomes. Knockdown of GRK5 expression leads to G2/M arrest, characterized by a prolonged G2 phase, which can be rescued by expression of wild type but not catalytically inactive GRK5. This G2/M arrest appears to be due to increased expression of p53, reduced activity of aurora A kinase and a subsequent delay in the activation of polo-like kinase 1. Overall, these studies demonstrate that GRK5 is localized in the centrosome and regulates microtubule nucleation and normal cell cycle progression.
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Affiliation(s)
- Allison M Michal
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
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29
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Chen YJ, Lin YP, Chow LP, Lee TC. Proteomic identification of Hsp70 as a new Plk1 substrate in arsenic trioxide-induced mitotically arrested cells. Proteomics 2011; 11:4331-45. [PMID: 21887822 DOI: 10.1002/pmic.201100329] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2011] [Revised: 08/09/2011] [Accepted: 08/18/2011] [Indexed: 01/01/2023]
Abstract
We previously demonstrated that when arsenic trioxide (ATO)-induced mitotically arrested HeLa S3 cells (AIMACs) were treated with staurosporine (SSP) the cells rapidly exited mitosis. To better define the cellular targets and the underlying mechanisms of AIMACs, we applied 2-D DIGE followed by LC-MS/MS analysis and showed that SSP induced a significant change in the phosphoproteome of AIMACs. Among the proteins whose phosphorylation was modulated by SSP, we identified Hsp70, Rad 23B, and eukaryotic translation initiation factor 4B as potentially new substrates of polo-like kinase 1 (Plk1), an essential serine/threonine kinase with versatile mitotic functions. Since Hsp70 is a stress protein responsible for ATO treatment, we further identified Thr(13) , Ser(362) , Ser(631) , and Ser(633) on Hsp70 intracellularly phosphorylated in AIMACs by combining TiO(2) phospho-peptides enrichment and MS/MS analysis. Using antibody specifically against phosph-Ser(631) Hsp70 and further aided by expression of kinase-dead Plk1 and pharmacological inhibition of Plk1, we concluded that Ser(631) on Hsp70 is phosphorylated by Plk1 in AIMACs. By immnuofluorescent staining, we found the colocalization of Hsp70 and Plk1 in AIMACs but not in interphase cells. In addition, Plk1-mediated phosphorylation of Hsp70 prevented AIMACs from mitotic death. Our results reveal that Hsp70 is a novel substrate of Plk1 and that its phosphorylation contributes to attenuation of ATO-induced mitotic abnormalities.
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Affiliation(s)
- Yu J Chen
- Graduate Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei, Taiwan
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30
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p16INK4A and p14ARF tumor suppressor pathways are deregulated in malignant rhabdoid tumors. J Neuropathol Exp Neurol 2011; 70:596-609. [PMID: 21666498 DOI: 10.1097/nen.0b013e31822146ca] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Malignant rhabdoid tumors (MRTs) are aggressive tumors associated with mutations in the SMARCB1 gene. In experimental systems, the loss of SMARCB1 is hypothesized to alter p16(INK4A) pathways resulting in the repression of tumor suppressors. To determine whether these pathways are deregulated in human MRT, we used immunohistochemistry on tissue microarrays to evaluate p16(INK4A)/E2F1/RB and p14(ARF)/MDM2/p53 pathways in 25 atypical teratoid/rhabdoid tumors (AT/RT) and 11 non-CNS MRT. p16(INK4A) was negative or showed focal weak expression. p16(INK4A) downstream targets CDK4/cyclin D1/ppRB were variably expressed at moderate to low levels; E2F1 was negative. Unexpectedly, p14(ARF) expression was seen in many cases, which correlated positively with p53 and inversely with MDM2 immunostaining in AT/RT. TP53 mutational analysis in 19 of 25 AT/RT and in 8 of 11 non-CNS MRT cases showed point mutations in only 3 AT/RT cases, suggesting that p53 expression was driven mainly by p14(ARF). Finally, nucleophosmin, a protein that stabilizes p53, was positive in most cases and colocalized with p53. Together, these data suggest that, in MRT, there is deregulation not only of p16(INK4A) but also of the p14(ARF) pathway. These results provide insights into cell cycle deregulation in the pathogenesis of human MRT and may aid in the design and evaluation of potential therapies for these tumors.
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31
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Alexander J, Lim D, Joughin BA, Hegemann B, Hutchins JRA, Ehrenberger T, Ivins F, Sessa F, Hudecz O, Nigg EA, Fry AM, Musacchio A, Stukenberg PT, Mechtler K, Peters JM, Smerdon SJ, Yaffe MB. Spatial exclusivity combined with positive and negative selection of phosphorylation motifs is the basis for context-dependent mitotic signaling. Sci Signal 2011; 4:ra42. [PMID: 21712545 DOI: 10.1126/scisignal.2001796] [Citation(s) in RCA: 134] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The timing and localization of events during mitosis are controlled by the regulated phosphorylation of proteins by the mitotic kinases, which include Aurora A, Aurora B, Nek2 (never in mitosis kinase 2), Plk1 (Polo-like kinase 1), and the cyclin-dependent kinase complex Cdk1/cyclin B. Although mitotic kinases can have overlapping subcellular localizations, each kinase appears to phosphorylate its substrates on distinct sites. To gain insight into the relative importance of local sequence context in kinase selectivity, identify previously unknown substrates of these five mitotic kinases, and explore potential mechanisms for substrate discrimination, we determined the optimal substrate motifs of these major mitotic kinases by positional scanning oriented peptide library screening (PS-OPLS). We verified individual motifs with in vitro peptide kinetic studies and used structural modeling to rationalize the kinase-specific selection of key motif-determining residues at the molecular level. Cross comparisons among the phosphorylation site selectivity motifs of these kinases revealed an evolutionarily conserved mutual exclusion mechanism in which the positively and negatively selected portions of the phosphorylation motifs of mitotic kinases, together with their subcellular localizations, result in proper substrate targeting in a coordinated manner during mitosis.
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Affiliation(s)
- Jes Alexander
- Koch Institute for Integrative Cancer Research, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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32
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Colombo E, Alcalay M, Pelicci PG. Nucleophosmin and its complex network: a possible therapeutic target in hematological diseases. Oncogene 2011; 30:2595-609. [PMID: 21278791 DOI: 10.1038/onc.2010.646] [Citation(s) in RCA: 165] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Nucleophosmin (NPM, also known as B23, numatrin or NO38) is a ubiquitously expressed phosphoprotein belonging to the nucleoplasmin family of chaperones. NPM is mainly localized in the nucleolus where it exerts many of its functions, but a proportion of the protein continuously shuttles between the nucleus and the cytoplasm. A growing number of cellular proteins have been described as physical interactors of NPM, and consequently, NPM is thought to have a relevant role in diverse cellular functions, including ribosome biogenesis, centrosome duplication, DNA repair and response to stress. NPM has been implicated in the pathogenesis of several human malignancies and intriguingly, it has been described both as an activating oncogene and a tumor suppressor, depending on cell type and protein levels. In fact, increased NPM expression is associated with different types of solid tumors whereas an impairment of NPM function is characteristic of a subgroup of hematolologic malignancies. A large body of experimental evidence links the deregulation of specific NPM functions to cellular transformation, yet the molecular mechanisms through which NPM contributes to tumorigenesis remain elusive. In this review, we have summarized current knowledge concerning NPM functions, and attempted to interpret its multifaceted and sometimes apparently contradictory activities in the context of both normal cellular homeostasis and neoplastic transformation.
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Affiliation(s)
- E Colombo
- Department of Experimental Oncology, European Institute of Oncology, Milan, Italy.
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33
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The Multifunctional Nucleolar Protein Nucleophosmin/NPM/B23 and the Nucleoplasmin Family of Proteins. THE NUCLEOLUS 2011. [PMCID: PMC7121557 DOI: 10.1007/978-1-4614-0514-6_10] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The nucleophosmin (NPM)/nucleoplasmin family of nuclear chaperones has three members: NPM1, NPM2, and NPM3. Nuclear chaperones serve to ensure proper assembly of nucleosomes and proper formation of higher order structures of chromatin. In fact, this family of proteins has such diverse functions in cellular processes such as chromatin remodeling, ribosome biogenesis, genome stability, centrosome replication, cell cycle, transcriptional regulation, apoptosis, and tumor suppression. Of the members of this family, NPM1 is the most studied and is the main focus of this review. NPM2 and NPM3 are less well characterized, and are also discussed wherever appropriate. The structure–function relationship of NPM proteins has largely been worked out. Other than the many processes in which NPM1 takes part, the major interest comes from its involvement in human cancers, particularly acute myeloid leukemia (AML). Its significance stems from the fact that AML with mutated NPM1 accounts for ∼30% of all AML cases and usually has good prognosis. Its clinical importance also comes from its involvement in virus replication, particularly in the era of outbreaks of infectious diseases.
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34
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Wang HF, Takenaka K, Nakanishi A, Miki Y. BRCA2 and nucleophosmin coregulate centrosome amplification and form a complex with the Rho effector kinase ROCK2. Cancer Res 2010; 71:68-77. [PMID: 21084279 DOI: 10.1158/0008-5472.can-10-0030] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BRCA2 germline mutations account for the majority of heredity breast and ovarian cancer. Besides its role in DNA damage repair, BRCA2 also plays an important role in cytokinesis, transcription regulation, and cancer cell proliferation. Recently, we reported that BRCA2 localizes to centrosomes as well as nuclei and the dysfunction of BRCA2 in a centrosome causes abnormalities in cell division. Here, we identified a nucleolar phosphoprotein, nucleophosmin (NPM), as a novel BRCA2-associated protein. We also detected the binding of BRCA2 to ROCK2, an effector of Rho small GTPase. Because it is known that ROCK2 binds to NPM at centrosomes, these 3 proteins may form a complex. NPM-binding region was within amino acids 639-1,000 of BRCA2. Exogenous expression of this BRCA2 region resulted in aberrant centrosome amplification and a high frequency of multinucleated cells. Our results suggested that a complex consisting of BRCA2, NPM, and ROCK2 maintains the numerical integrity of centrosomes and accurate cell division and that dysfunction of this regulation might be involved in the tumorigenesis of breast cancer.
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Affiliation(s)
- Hui-Feng Wang
- Department of Molecular Genetics, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
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35
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Lin CY, Tan BCM, Liu H, Shih CJ, Chien KY, Lin CL, Yung BYM. Dephosphorylation of nucleophosmin by PP1β facilitates pRB binding and consequent E2F1-dependent DNA repair. Mol Biol Cell 2010; 21:4409-17. [PMID: 20962268 PMCID: PMC3002393 DOI: 10.1091/mbc.e10-03-0239] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
We report a new pathway through which PP1β signals to nucleophosmin (NPM) in response to DNA damage. UV induces dephosphorylation of NPM at multiple sites, leading to enhancement of complex formation between NPM and retinoblastoma tumor suppressor protein and the subsequent upregulation of E2F1. Consequently, such signaling pathway potentiates the cellular DNA repair capacity. Nucleophosmin (NPM) is an important phosphoprotein with pleiotropic functions in various cellular processes. Although phosphorylation has been postulated as an important functional determinant, possible regulatory roles of this modification on NPM are not fully characterized. Here, we find that NPM is dephosphorylated on various threonine residues (Thr199 and Thr234/237) in response to UV-induced DNA damage. Further experiments indicate that the serine/threonine protein phosphatase PP1β is a physiological NPM phosphatase under both the genotoxic stress and growth conditions. As a consequence, NPM in its hypophosphorylated state facilitates DNA repair. Finally, our results suggest that one possible mechanism of this protective response lies in enhanced NPM-retinoblastoma tumor suppressor protein (pRB) interaction, leading to the relief of the repressive pRB–E2F1 circuitry and the consequent transcriptional activation of E2F1 and several downstream DNA repair genes. Thus, this study unveils a key phosphatase of NPM and highlights a novel mechanism by which the PP1β–NPM pathway contributes to cellular DNA damage response.
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Affiliation(s)
- Chiao Yun Lin
- Department of Pharmacology, College of Medicine, Chang Gung University, Tao-Yuan 333, Taiwan
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36
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Park JE, Soung NK, Johmura Y, Kang YH, Liao C, Lee KH, Park CH, Nicklaus MC, Lee KS. Polo-box domain: a versatile mediator of polo-like kinase function. Cell Mol Life Sci 2010; 67:1957-70. [PMID: 20148280 PMCID: PMC2877763 DOI: 10.1007/s00018-010-0279-9] [Citation(s) in RCA: 130] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2009] [Revised: 01/13/2010] [Accepted: 01/19/2010] [Indexed: 12/23/2022]
Abstract
Members of the polo subfamily of protein kinases have emerged as important regulators in diverse aspects of the cell cycle and cell proliferation. A large body of evidence suggests that a highly conserved polo-box domain (PBD) present in the C-terminal non-catalytic region of polo kinases plays a pivotal role in the function of these enzymes. Recent advances in our comprehension of the mechanisms underlying mammalian polo-like kinase 1 (Plk1)-dependent protein-protein interactions revealed that the PBD serves as an essential molecular mediator that brings the kinase domain of Plk1 into proximity with its substrates, mainly through phospho-dependent interactions with its target proteins. In this review, current understanding of the structure and functions of PBD, mode of PBD-dependent interactions and substrate phosphorylation, and other phospho-independent functions of PBD are discussed.
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Affiliation(s)
- Jung-Eun Park
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 9000 Rockville Pike, Bldg. 37, Rm. 3118, Bethesda, MD 20892-4258 USA
| | - Nak-Kyun Soung
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 9000 Rockville Pike, Bldg. 37, Rm. 3118, Bethesda, MD 20892-4258 USA
| | - Yoshikazu Johmura
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 9000 Rockville Pike, Bldg. 37, Rm. 3118, Bethesda, MD 20892-4258 USA
| | - Young H. Kang
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 9000 Rockville Pike, Bldg. 37, Rm. 3118, Bethesda, MD 20892-4258 USA
| | - Chenzhong Liao
- Chemical Biology Laboratory, Center for Cancer Research, National Cancer Institute-Frederick, National Institutes of Health, Frederick, MD 21702 USA
| | - Kyung H. Lee
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 9000 Rockville Pike, Bldg. 37, Rm. 3118, Bethesda, MD 20892-4258 USA
| | - Chi Hoon Park
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 9000 Rockville Pike, Bldg. 37, Rm. 3118, Bethesda, MD 20892-4258 USA
| | - Marc C. Nicklaus
- Chemical Biology Laboratory, Center for Cancer Research, National Cancer Institute-Frederick, National Institutes of Health, Frederick, MD 21702 USA
| | - Kyung S. Lee
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 9000 Rockville Pike, Bldg. 37, Rm. 3118, Bethesda, MD 20892-4258 USA
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37
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Krause A, Hoffmann I. Polo-like kinase 2-dependent phosphorylation of NPM/B23 on serine 4 triggers centriole duplication. PLoS One 2010; 5:e9849. [PMID: 20352051 PMCID: PMC2844433 DOI: 10.1371/journal.pone.0009849] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2009] [Accepted: 03/04/2010] [Indexed: 11/18/2022] Open
Abstract
Duplication of the centrosome is well controlled during faithful cell division while deregulation of this process leads to supernumary centrosomes, chromosome missegregation and aneuploidy, a hallmark of many cancer cells. We previously reported that Polo-like kinase 2 (Plk2) is activated near the G1/S phase transition, and regulates the reproduction of centrosomes. In search for Plk2 interacting proteins we have identified NPM/B23 (Nucleophosmin) as a novel Plk2 binding partner. We find that Plk2 and NPM/B23 interact in vitro in a Polo-box dependent manner. An association between both proteins was also observed in vivo. Moreover, we show that Plk2 phosphorylates NPM/B23 on serine 4 in vivo in S-phase. Notably, expression of a non-phosphorylatable NPM/B23 S4A mutant interferes with centriole reduplication in S-phase arrested cells and leads to a dilution of centriole numbers in unperturbed U2OS cells. The corresponding phospho-mimicking mutants have the opposite effect and their expression leads to the accumulation of centrioles. These findings suggest that NPM/B23 is a direct target of Plk2 in the regulation of centriole duplication and that phosphorylation on serine 4 can trigger this process.
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Affiliation(s)
- Annekatrin Krause
- Cell Cycle Control and Carcinogenesis, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Ingrid Hoffmann
- Cell Cycle Control and Carcinogenesis, German Cancer Research Center (DKFZ), Heidelberg, Germany
- * E-mail:
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38
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Falini B. Acute myeloid leukemia with mutated nucleophosmin (NPM1): molecular, pathological, and clinical features. Cancer Treat Res 2010; 145:149-168. [PMID: 20306250 DOI: 10.1007/978-0-387-69259-3_9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The NPM1 gene encodes for nucleophosmin, a nucleolus-located shuttling protein that is involved in multiple cell functions, including regulation of ribosome biogenesis, control of centrosome duplication and preservation of ARF tumor suppressor integrity. The NPM1 gene is specifically mutated in about 30% acute myeloid leukemia (AML) but not in other human neoplasms. Mutations cause crucial changes at the C-terminus of the NPM1 protein that are responsible for the aberrant nuclear export and accumulation of NPM1 mutants in the cytoplasm of leukemic cells. Diagnosis of AML with mutated NPM1 can be done using molecular techniques, immunohistochemistry (looking at cytoplasmic dislocation of nucleophosmin that is predictive of NPM1 mutations) and Western blotting with antibodies specifically directed against NPM1 mutants. Because of its distinctive molecular, pathological, immunophenotypic and prognostic features, AML with mutated NPM1 (synonym: NPMc+ AML) has been included, as a new provisional entity, in the 2008 World Health Organization (WHO) classification of myeloid neoplasms.
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39
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Rau R, Brown P. Nucleophosmin (NPM1) mutations in adult and childhood acute myeloid leukaemia: towards definition of a new leukaemia entity. Hematol Oncol 2009; 27:171-81. [PMID: 19569254 DOI: 10.1002/hon.904] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Nucleophosmin (NPM) is a ubiquitously expressed chaperone protein that shuttles rapidly between the nucleus and cytoplasm, but predominantly resides in the nucleolus. It plays key roles in ribosome biogenesis, centrosome duplication, genomic stability, cell cycle progression and apoptosis. Somatic mutations in exon 12 of the NPM gene (NPM1) are the most frequent genetic abnormality in adult acute myeloid leukaemia (AML), found in approximately 35% of all cases and up to 60% of patients with normal karyotype (NK) AML. In children, NPM1 mutations are far less frequent, occurring in 8-10% of all AML cases, and in approximately 25% of those with a NK. NPM1 mutations lead to aberrant localization of the NPM protein into the cytoplasm, thus the designation, NPMc+ AML. NPMc+ AML is seen predominantly in patients with a NK and is essentially mutually exclusive of recurrent chromosomal translocations. Patients with NPM1 mutations are twice as likely as those who lack an NPM1 mutation to also have a FMS-like tyrosine kinase (FLT3) internal tandem duplication (ITD) mutation. NPMc+ AML is also characterized by a unique gene expression signature and microRNA signature. NPMc+ AML has important prognostic significance, as NPMc+ AML, in the absence of a coexisting FLT3-ITD mutation, is associated with a favourable outcome. NPM1 mutations have also shown great stability during disease evolution, and therefore represent a possible marker for minimal residual disease detection. Given its distinctive biologic and clinical features and its clear clinical relevance, NPMc+ AML is included as a provisional entity in the 2008 WHO classifications. There is still much to be learned about this genetic alteration, including its exact role in leukaemogenesis, how it interacts with other mutations and why it confers a more favourable prognosis. Further, it represents a potential therapeutic target warranting research aimed at identifying novel small molecules with activity in NPMc+ AML.
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Affiliation(s)
- Rachel Rau
- Departments of Oncology and Pediatrics, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
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40
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Du W, Zhou Y, Pike S, Pang Q. NPM phosphorylation stimulates Cdk1, overrides G2/M checkpoint and increases leukemic blasts in mice. Carcinogenesis 2009; 31:302-10. [PMID: 19933706 DOI: 10.1093/carcin/bgp270] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
An elevated level of nucleophosmin (NPM) is often found in actively proliferative cells including human tumors. To identify the regulatory role for NPM phosphorylation in proliferation and cell cycle control, a series of mutants targeting the consensus cyclin-dependent kinase (CDK) phosphorylation sites was created to mimic or abrogate either single-site or multi-site phosphorylation. Simultaneous inactivation of two CDK phosphorylation sites at Ser10 and Ser70 (NPM-AA) induced G(2)/M cell cycle arrest, phosphorylation of Cdk1 at Tyr15 (Cdc2(Tyr15)) and increased cytoplasmic accumulation of Cdc25C. Strikingly, stress-induced Cdk1(Tyr15) and Cdc25C sequestration was suppressed by expression of a phosphomimetic NPM mutant created on the same CDK sites (S10E/S70E, NPM-EE). Further analysis revealed that phosphorylation of NPM at both Ser10 and Ser70 was required for proper interaction between Cdk1 and Cdc25C. Moreover, NPM-EE directly bound to Cdc25C and prevented phosphorylation of Cdc25C at Ser216 during mitosis. Finally, NPM-EE overrided stress-induced G(2)/M arrest and increased leukemia blasts in a NOD/SCID xenograft model. Thus, these findings reveal a novel function of NPM on regulation of cell cycle progression, in which phosphorylation of NPM controls cell cycle progression at G(2)/M transition through modulation of Cdk1 and Cdc25C activities.
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Affiliation(s)
- Wei Du
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
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41
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Gautier VW, Gu L, O'Donoghue N, Pennington S, Sheehy N, Hall WW. In vitro nuclear interactome of the HIV-1 Tat protein. Retrovirology 2009; 6:47. [PMID: 19454010 PMCID: PMC2702331 DOI: 10.1186/1742-4690-6-47] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2008] [Accepted: 05/19/2009] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND One facet of the complexity underlying the biology of HIV-1 resides not only in its limited number of viral proteins, but in the extensive repertoire of cellular proteins they interact with and their higher-order assembly. HIV-1 encodes the regulatory protein Tat (86-101aa), which is essential for HIV-1 replication and primarily orchestrates HIV-1 provirus transcriptional regulation. Previous studies have demonstrated that Tat function is highly dependent on specific interactions with a range of cellular proteins. However they can only partially account for the intricate molecular mechanisms underlying the dynamics of proviral gene expression. To obtain a comprehensive nuclear interaction map of Tat in T-cells, we have designed a proteomic strategy based on affinity chromatography coupled with mass spectrometry. RESULTS Our approach resulted in the identification of a total of 183 candidates as Tat nuclear partners, 90% of which have not been previously characterised. Subsequently we applied in silico analysis, to validate and characterise our dataset which revealed that the Tat nuclear interactome exhibits unique signature(s). First, motif composition analysis highlighted that our dataset is enriched for domains mediating protein, RNA and DNA interactions, and helicase and ATPase activities. Secondly, functional classification and network reconstruction clearly depicted Tat as a polyvalent protein adaptor and positioned Tat at the nexus of a densely interconnected interaction network involved in a range of biological processes which included gene expression regulation, RNA biogenesis, chromatin structure, chromosome organisation, DNA replication and nuclear architecture. CONCLUSION We have completed the in vitro Tat nuclear interactome and have highlighted its modular network properties and particularly those involved in the coordination of gene expression by Tat. Ultimately, the highly specialised set of molecular interactions identified will provide a framework to further advance our understanding of the mechanisms of HIV-1 proviral gene silencing and activation.
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Affiliation(s)
- Virginie W Gautier
- UCD-Centre for Research in Infectious Diseases, School of Medicine and Medical Science, University College Dublin (UCD), Belfield, Dublin 4, Ireland.
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van Wijk E, Kersten FFJ, Kartono A, Mans DA, Brandwijk K, Letteboer SJF, Peters TA, Märker T, Yan X, Cremers CWRJ, Cremers FPM, Wolfrum U, Roepman R, Kremer H. Usher syndrome and Leber congenital amaurosis are molecularly linked via a novel isoform of the centrosomal ninein-like protein. Hum Mol Genet 2008; 18:51-64. [PMID: 18826961 DOI: 10.1093/hmg/ddn312] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Usher syndrome (USH) and Leber congenital amaurosis (LCA) are autosomal recessive disorders resulting in syndromic and non-syndromic forms of blindness. In order to gain insight into the pathogenic mechanisms underlying retinal degeneration, we searched for interacting proteins of USH2A isoform B (USH2A(isoB)) and the LCA5-encoded protein lebercilin. We identified a novel isoform of the centrosomal ninein-like protein, hereby named Nlp isoform B (Nlp(isoB)), as a common interactor. Although we identified the capacity of this protein to bind calcium with one of its three EF-hand domains, the interacton with USH2A(isoB) did not depend on this. Upon expression in ARPE-19 cells, recombinant Nlp(isoB), lebercilin and USH2A(isoB) were all found to co-localize at the centrosomes. Staining of retinal sections with specific antibodies against all three proteins revealed their co-localization at the basal bodies of the photoreceptor-connecting cilia. Based on this subcellular localization and the nature of their previously identified binding partners, we hypothesize that the pathogenic mechanisms for LCA and USH show significant overlap and involve defects in ciliogenesis, cilia maintenance and intraflagellar and/or microtubule-based transport. The direct association of Nlp(isoB) with USH2A(isoB) and lebercilin indicates that Nlp can be considered as a novel candidate gene for USH, LCA and allied retinal ciliopathies.
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Affiliation(s)
- Erwin van Wijk
- Department of Otorhinolaryngology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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Pelech S, Jelinkova L, Susor A, Zhang H, Shi X, Pavlok A, Kubelka M, Kovarova H. Antibody Microarray Analyses of Signal Transduction Protein Expression and Phosphorylation during Porcine Oocyte Maturation. J Proteome Res 2008; 7:2860-71. [DOI: 10.1021/pr800082a] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Steven Pelech
- Kinexus Bioinformatics Corporation, Suite 1, 8755 Ash Street, Vancouver, BC, Canada V6P 6T3, Department of Medicine, University of British Columbia, Vancouver, BC, Canada, and Department of Reproductive and Developmental Biology, Institute of Animal Physiology and Genetics, Rumburska 89, Libechov, Czech Republic
| | - Lucie Jelinkova
- Kinexus Bioinformatics Corporation, Suite 1, 8755 Ash Street, Vancouver, BC, Canada V6P 6T3, Department of Medicine, University of British Columbia, Vancouver, BC, Canada, and Department of Reproductive and Developmental Biology, Institute of Animal Physiology and Genetics, Rumburska 89, Libechov, Czech Republic
| | - Andrej Susor
- Kinexus Bioinformatics Corporation, Suite 1, 8755 Ash Street, Vancouver, BC, Canada V6P 6T3, Department of Medicine, University of British Columbia, Vancouver, BC, Canada, and Department of Reproductive and Developmental Biology, Institute of Animal Physiology and Genetics, Rumburska 89, Libechov, Czech Republic
| | - Hong Zhang
- Kinexus Bioinformatics Corporation, Suite 1, 8755 Ash Street, Vancouver, BC, Canada V6P 6T3, Department of Medicine, University of British Columbia, Vancouver, BC, Canada, and Department of Reproductive and Developmental Biology, Institute of Animal Physiology and Genetics, Rumburska 89, Libechov, Czech Republic
| | - Xiaoqing Shi
- Kinexus Bioinformatics Corporation, Suite 1, 8755 Ash Street, Vancouver, BC, Canada V6P 6T3, Department of Medicine, University of British Columbia, Vancouver, BC, Canada, and Department of Reproductive and Developmental Biology, Institute of Animal Physiology and Genetics, Rumburska 89, Libechov, Czech Republic
| | - Antonin Pavlok
- Kinexus Bioinformatics Corporation, Suite 1, 8755 Ash Street, Vancouver, BC, Canada V6P 6T3, Department of Medicine, University of British Columbia, Vancouver, BC, Canada, and Department of Reproductive and Developmental Biology, Institute of Animal Physiology and Genetics, Rumburska 89, Libechov, Czech Republic
| | - Michal Kubelka
- Kinexus Bioinformatics Corporation, Suite 1, 8755 Ash Street, Vancouver, BC, Canada V6P 6T3, Department of Medicine, University of British Columbia, Vancouver, BC, Canada, and Department of Reproductive and Developmental Biology, Institute of Animal Physiology and Genetics, Rumburska 89, Libechov, Czech Republic
| | - Hana Kovarova
- Kinexus Bioinformatics Corporation, Suite 1, 8755 Ash Street, Vancouver, BC, Canada V6P 6T3, Department of Medicine, University of British Columbia, Vancouver, BC, Canada, and Department of Reproductive and Developmental Biology, Institute of Animal Physiology and Genetics, Rumburska 89, Libechov, Czech Republic
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Aranda-Orgillés B, Trockenbacher A, Winter J, Aigner J, Köhler A, Jastrzebska E, Stahl J, Müller EC, Otto A, Wanker EE, Schneider R, Schweiger S. The Opitz syndrome gene product MID1 assembles a microtubule-associated ribonucleoprotein complex. Hum Genet 2008; 123:163-76. [PMID: 18172692 PMCID: PMC3774420 DOI: 10.1007/s00439-007-0456-6] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2007] [Accepted: 12/15/2007] [Indexed: 01/31/2023]
Abstract
Opitz BBB/G syndrome (OS) is a heterogenous malformation syndrome mainly characterised by hypertelorism and hypospadias. In addition, patients may present with several other defects of the ventral midline such as cleft lip and palate and congenital heart defects. The syndrome-causing gene encodes the X-linked E3 ubiquitin ligase MID1 that mediates ubiquitin-specific modification and degradation of the catalytic subunit of the translation regulator protein phosphatase 2A (PP2A). Here, we show that the MID1 protein also associates with elongation factor 1alpha (EF-1alpha) and several other proteins involved in mRNA transport and translation, including RACK1, Annexin A2, Nucleophosmin and proteins of the small ribosomal subunits. Mutant MID1 proteins as found in OS patients lose the ability to interact with EF-1alpha. The composition of the MID1 protein complex was determined by several independent methods: (1) yeast two-hybrid screening and (2) immunofluorescence, (3) a biochemical approach involving affinity purification of the complex, (4) co-fractionation in a microtubule assembly assay and (5) immunoprecipitation. Moreover, we show that the cytoskeleton-bound MID1/translation factor complex specifically associates with G- and U-rich RNAs and incorporates MID1 mRNA, thus forming a microtubule-associated ribonucleoprotein (RNP) complex. Our data suggest a novel function of the OS gene product in directing translational control to the cytoskeleton. The dysfunction of this mechanism would lead to malfunction of microtubule-associated protein translation and to the development of OS.
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Affiliation(s)
- Beatriz Aranda-Orgillés
- />Max-Planck Institute for Molecular Genetics, Ihnestr. 73, 14195 Berlin, Germany
- />Department of Biology, Chemistry and Pharmacy, Free University Berlin, Thielallee 63, 14195 Berlin, Germany
| | - Alexander Trockenbacher
- />Max-Planck Institute for Molecular Genetics, Ihnestr. 73, 14195 Berlin, Germany
- />Institute of Biochemistry, Center for Molecular Biosciences Innsbruck (CMBI), University Innsbruck, Peter-Mayr-Str. 1a, 6020 Innsbruck, Austria
| | - Jennifer Winter
- />Max-Planck Institute for Molecular Genetics, Ihnestr. 73, 14195 Berlin, Germany
| | - Johanna Aigner
- />Max-Planck Institute for Molecular Genetics, Ihnestr. 73, 14195 Berlin, Germany
| | - Andrea Köhler
- />Institute of Biochemistry, Center for Molecular Biosciences Innsbruck (CMBI), University Innsbruck, Peter-Mayr-Str. 1a, 6020 Innsbruck, Austria
| | - Ewa Jastrzebska
- />Max-Planck Institute for Molecular Genetics, Ihnestr. 73, 14195 Berlin, Germany
- />Department of Dermatology, Charité, Schumannstr. 21-22, 10117 Berlin, Germany
| | - Joachim Stahl
- />Max-Delbrueck Center of Molecular Medicine, Robert-Roessle-Str. 10, 13125 Berlin, Germany
| | - Eva-Christina Müller
- />Max-Delbrueck Center of Molecular Medicine, Robert-Roessle-Str. 10, 13125 Berlin, Germany
| | - Albrecht Otto
- />Max-Delbrueck Center of Molecular Medicine, Robert-Roessle-Str. 10, 13125 Berlin, Germany
| | - Erich E. Wanker
- />Max-Delbrueck Center of Molecular Medicine, Robert-Roessle-Str. 10, 13125 Berlin, Germany
| | - Rainer Schneider
- />Max-Planck Institute for Molecular Genetics, Ihnestr. 73, 14195 Berlin, Germany
- />Institute of Biochemistry, Center for Molecular Biosciences Innsbruck (CMBI), University Innsbruck, Peter-Mayr-Str. 1a, 6020 Innsbruck, Austria
| | - Susann Schweiger
- />Max-Planck Institute for Molecular Genetics, Ihnestr. 73, 14195 Berlin, Germany
- />Medical School, Division of Pathology and Neuroscience, University of Dundee, DD1 9SY Dundee, UK
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45
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den Hollander AI, Koenekoop RK, Mohamed MD, Arts HH, Boldt K, Towns KV, Sedmak T, Beer M, Nagel-Wolfrum K, McKibbin M, Dharmaraj S, Lopez I, Ivings L, Williams GA, Springell K, Woods CG, Jafri H, Rashid Y, Strom TM, van der Zwaag B, Gosens I, Kersten FFJ, van Wijk E, Veltman JA, Zonneveld MN, van Beersum SEC, Maumenee IH, Wolfrum U, Cheetham ME, Ueffing M, Cremers FPM, Inglehearn CF, Roepman R. Mutations in LCA5, encoding the ciliary protein lebercilin, cause Leber congenital amaurosis. Nat Genet 2007; 39:889-95. [PMID: 17546029 DOI: 10.1038/ng2066] [Citation(s) in RCA: 125] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2007] [Accepted: 05/10/2007] [Indexed: 01/24/2023]
Abstract
Leber congenital amaurosis (LCA) causes blindness or severe visual impairment at or within a few months of birth. Here we show, using homozygosity mapping, that the LCA5 gene on chromosome 6q14, which encodes the previously unknown ciliary protein lebercilin, is associated with this disease. We detected homozygous nonsense and frameshift mutations in LCA5 in five families affected with LCA. In a sixth family, the LCA5 transcript was completely absent. LCA5 is expressed widely throughout development, although the phenotype in affected individuals is limited to the eye. Lebercilin localizes to the connecting cilia of photoreceptors and to the microtubules, centrioles and primary cilia of cultured mammalian cells. Using tandem affinity purification, we identified 24 proteins that link lebercilin to centrosomal and ciliary functions. Members of this interactome represent candidate genes for LCA and other ciliopathies. Our findings emphasize the emerging role of disrupted ciliary processes in the molecular pathogenesis of LCA.
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Affiliation(s)
- Anneke I den Hollander
- Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
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46
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Lowery DM, Clauser KR, Hjerrild M, Lim D, Alexander J, Kishi K, Ong SE, Gammeltoft S, Carr SA, Yaffe MB. Proteomic screen defines the Polo-box domain interactome and identifies Rock2 as a Plk1 substrate. EMBO J 2007; 26:2262-73. [PMID: 17446864 PMCID: PMC1864981 DOI: 10.1038/sj.emboj.7601683] [Citation(s) in RCA: 195] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2006] [Accepted: 03/14/2007] [Indexed: 11/09/2022] Open
Abstract
Polo-like kinase-1 (Plk1) phosphorylates a number of mitotic substrates, but the diversity of Plk1-dependent processes suggests the existence of additional targets. Plk1 contains a specialized phosphoserine-threonine binding domain, the Polo-box domain (PBD), postulated to target the kinase to its substrates. Using the specialized PBD of Plk1 as an affinity capture agent, we performed a screen to define the mitotic Plk1-PBD interactome by mass spectrometry. We identified 622 proteins that showed phosphorylation-dependent mitosis-specific interactions, including proteins involved in well-established Plk1-regulated processes, and in processes not previously linked to Plk1 such as translational control, RNA processing, and vesicle transport. Many proteins identified in our screen play important roles in cytokinesis, where, in mammalian cells, the detailed mechanistic role of Plk1 remains poorly defined. We go on to characterize the mitosis-specific interaction of the Plk1-PBD with the cytokinesis effector kinase Rho-associated coiled-coil domain-containing protein kinase 2 (Rock2), demonstrate that Rock2 is a Plk1 substrate, and show that Rock2 colocalizes with Plk1 during cytokinesis. Finally, we show that Plk1 and RhoA function together to maximally enhance Rock2 kinase activity in vitro and within cells, and implicate Plk1 as a central regulator of multiple pathways that synergistically converge to regulate actomyosin ring contraction during cleavage furrow ingression.
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Affiliation(s)
- Drew M Lowery
- Departments of Biology and Biological Engineering, Center for Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA
| | | | - Majbrit Hjerrild
- Departments of Biology and Biological Engineering, Center for Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Clinical Biochemistry, Glostrup Hospital, Glostrup, Denmark
| | - Dan Lim
- Departments of Biology and Biological Engineering, Center for Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Jes Alexander
- Departments of Biology and Biological Engineering, Center for Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Kazuhiro Kishi
- Departments of Biology and Biological Engineering, Center for Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Shao-En Ong
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Steen Gammeltoft
- Department of Clinical Biochemistry, Glostrup Hospital, Glostrup, Denmark
| | - Steven A Carr
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Michael B Yaffe
- Departments of Biology and Biological Engineering, Center for Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
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Klegeris A, Pelech S, Giasson BI, Maguire J, Zhang H, McGeer EG, McGeer PL. Alpha-synuclein activates stress signaling protein kinases in THP-1 cells and microglia. Neurobiol Aging 2006; 29:739-52. [PMID: 17166628 DOI: 10.1016/j.neurobiolaging.2006.11.013] [Citation(s) in RCA: 166] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2006] [Revised: 11/17/2006] [Accepted: 11/19/2006] [Indexed: 01/28/2023]
Abstract
Here we show that alpha-synuclein, a major constituent of Lewy bodies, induces inflammation in human microglial and human THP-1 cells. Secretions from such stimulated THP-1 cells contain increased levels of IL-1beta and TNF-alpha. When stimulated by alpha-synuclein in combination with IFN-gamma, secretions from the cells also become toxic towards SH-SY5Y neuroblastoma cells. The A30P, E46K and A53T alpha-synuclein mutations, which induce Parkinson's disease, are more potent than normal alpha-synuclein in the induction of such cytotoxicity. To investigate the signaling mechanisms evoked, protein phosphorylation profiling was applied. At least 81 target phospho-sites were identified. Large increases were induced in the three major mitogen-activated protein (MAP) kinase pathways: p38 MAP kinase, extracellular regulated protein-serine kinase (ERK)1/2 and c-Jun-N-terminal kinase (JNK). Upregulation occurred within minutes following exposure to alpha-synuclein, which is consistent with a receptor-mediated effect. These findings demonstrate that alpha-synuclein acts as a potent inflammatory stimulator of microglial cells, and that inhibitors of such stimulation might be beneficial in the treatment of Parkinson's disease and other synucleinopathies.
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Affiliation(s)
- Andis Klegeris
- Kinsmen Laboratory of Neurological Research, University of British Columbia, 2255 Wesbrook Mall, Vancouver, BC V6T 1Z3, Canada
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Abstract
Nucleophosmin (NPM) is a nucleolar phosphoprotein that shuttles between the nucleus and cytoplasm during the cell cycle. NPM has several interacting partners and diverse cellular functions, including the processing of ribosomal RNA, centrosome duplication and the control of cellular processes to ensure genomic stability. Subcellular localization of NPM appears to be strongly correlated with NPM functions and cell proliferation. NPM is phosphorylated mainly at its central acidic domain by several upstream kinases, and its phosphorylation appears to be involved in regulating its functions in ribosome biogenesis and centrosome duplication. Recent studies suggest that NPM may act as a licensing factor to maintain proper centrosome duplication and that the Ran/CRM1 nucleocytoplasmic complex regulates local trafficking of NPM to centrosomes by interacting through its nuclear export sequence motif. Here, we provide a brief overview of NPM functions and its roles in human carcinogenesis, and discuss our recent findings related to the potential mechanisms underlying its regulation of centrosome duplication.
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Affiliation(s)
- Mi Jung Lim
- Laboratory of Human Carcinogenesis, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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Falini B, Nicoletti I, Martelli MF, Mecucci C. Acute myeloid leukemia carrying cytoplasmic/mutated nucleophosmin (NPMc+ AML): biologic and clinical features. Blood 2006; 109:874-85. [PMID: 17008539 DOI: 10.1182/blood-2006-07-012252] [Citation(s) in RCA: 392] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The nucleophosmin (NPM1) gene encodes for a multifunctional nucleocytoplasmic shuttling protein that is localized mainly in the nucleolus. NPM1 mutations occur in 50% to 60% of adult acute myeloid leukemia with normal karyotype (AML-NK) and generate NPM mutants that localize aberrantly in the leukemic-cell cytoplasm, hence the term NPM-cytoplasmic positive (NPMc+ AML). Cytoplasmic NPM accumulation is caused by the concerted action of 2 alterations at mutant C-terminus, that is, changes of tryptophan(s) 288 and 290 (or only 290) and creation of an additional nuclear export signal (NES) motif. NPMc+ AML shows increased frequency in adults and females, wide morphologic spectrum, multilineage involvement, high frequency of FLT3-ITD, CD34 negativity, and a distinct gene-expression profile. Analysis of mutated NPM has important clinical and pathologic applications. Immunohistochemical detection of cytoplasmic NPM predicts NPM1 mutations and helps rationalize cytogenetic/molecular studies in AML. NPM1 mutations in absence of FLT3-ITD identify a prognostically favorable subgroup in the heterogeneous AML-NK category. Due to their frequency and stability, NPM1 mutations may become a new tool for monitoring minimal residual disease in AML-NK. Future studies should focus on clarifying how NPM mutants promote leukemia, integrating NPMc+ AML in the upcoming World Health Organization leukemia classification, and eventually developing specific antileukemic drugs.
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Grisendi S, Pandolfi PP. Two decades of cancer genetics: from specificity to pleiotropic networks. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2006; 70:83-91. [PMID: 16869741 DOI: 10.1101/sqb.2005.70.023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Modeling cancer in mice has reached an even greater relevance in the field of hematological malignancies, due to the already advanced characterization of the molecular basis of many hematological disorders. These mouse models have often allowed us to achieve insight into the pathogenesis of the human disease as well as to test novel therapeutic modalities in preclinical studies. However, one of the most rewarding cultural shifts triggered by these modeling efforts stems from what was originally perceived as background noise or modeling inaccuracy. Manipulation of the involved genes often triggered cancer susceptibility in cell types other than the hematopoietic lineages. This prompted us to challenge a fundamental misconception in cancer genetics that the approximately 200 genes directly involved in chromosomal translocations associated with hematopoietic malignancies are specifically and functionally restricted to leukemia/lymphoma pathogenesis only. The genetics underlying the pathogenesis of leukemia and lymphoma have historically been regarded as distinct from those underlying the pathogenesis of solid tumors because hematopoietic malignancies are often associated with characteristic chromosomal translocations that are leukemia- or lymphoma-specific. In this paper, we discuss how leukemia/lymphoma genes indeed participate in fundamental proto-oncogenic and growth-suppressive networks and may play a wider role in cancer pathogenesis. We focus on paradigmatic examples such as c-myc and PML, as well as on more recent findings from our laboratory concerning the role of NPM in tumorigenesis.
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Affiliation(s)
- S Grisendi
- Cancer Biology & Genetics Program, Department of Pathology, Sloan-Kettering Institute, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA
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