1
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Valdez V, Ma M, Gouveia B, Zhang R, Petry S. HURP facilitates spindle assembly by stabilizing microtubules and working synergistically with TPX2. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.18.571906. [PMID: 38187686 PMCID: PMC10769297 DOI: 10.1101/2023.12.18.571906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
In large vertebrate spindles, the majority of microtubules are formed via branching microtubule nucleation, whereby microtubules nucleate along the side of pre-existing microtubules. Hepatoma up-regulated protein (HURP) is a microtubule-associated protein that has been implicated in spindle assembly, but its mode of action is yet to be defined. In this study, we show that HURP is necessary for RanGTP-induced branching microtubule nucleation in Xenopus egg extract. Specifically, HURP stabilizes the microtubule lattice to promote microtubule formation from γ-TuRC. This function is shifted to promote branching microtubule nucleation in the presence of TPX2, another branching-promoting factor, as HURP's localization to microtubules is enhanced by TPX2 condensation. Lastly, we provide a structure of HURP on the microtubule lattice, revealing how HURP binding stabilizes the microtubule lattice. We propose a model in which HURP stabilizes microtubules during their formation, and TPX2 preferentially enriches HURP to microtubules to promote branching microtubule nucleation and thus spindle assembly.
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Affiliation(s)
- Venecia Valdez
- Princeton University, Department of Molecular Biology, Princeton, New Jersey, United States
| | - Meisheng Ma
- Department of Biochemistry and Molecular Biophysics, Washington University in St. Louis, School of Medicine (St. Louis, Missouri, United States)
- Present address: Department of Histology and Embryology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology (Wuhan, Hubei, China)
| | - Bernardo Gouveia
- Princeton University, Department of Chemical and Biological Engineering, Princeton, New Jersey, United States
| | - Rui Zhang
- Department of Biochemistry and Molecular Biophysics, Washington University in St. Louis, School of Medicine (St. Louis, Missouri, United States)
| | - Sabine Petry
- Princeton University, Department of Molecular Biology, Princeton, New Jersey, United States
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2
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Huang YRJ, Chiu SC, Tseng JS, Chen JMM, Wei TYW, Chu CY, Kao HTE, Yang CYO, Shih YCE, Yang TY, Chiu KY, Teng CLJ, Yu CTR. The JMJD6/HURP axis promotes cell migration via NF-κB-dependent centrosome repositioning and Cdc42-mediated Golgi repositioning. J Cell Physiol 2022; 237:4517-4530. [PMID: 36250981 DOI: 10.1002/jcp.30900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Revised: 09/19/2022] [Accepted: 10/03/2022] [Indexed: 11/05/2022]
Abstract
Golgi apparatus (GA) and centrosome reposition toward cell leading end during directional cell migration in a coupling way, thereby determining cell polarity by transporting essential factors to the proximal plasma membrane. The study provides mechanistic insights into how GA repositioning (GR) is regulated, and how GR and centrosome repositioning (CR) are coupled. Our previous published works reveals that PRMT5 methylates HURP at R122 and the HURP m122 inhibits GR and cell migration by stabilizing GA-associated acetyl-tubulin and then rigidifying GA. The current study further shows that the demethylase JMJD6-guided demethylation of HURP at R122 promotes GR and cell migration. The HURP methylation mimicking mutant 122 F blocks JMJD6-induced GR and cell migration, suggesting JMJD6 relays GR stimulating signal to HURP. Mechanistic studies reveal that the HURP methylation deficiency mutant 122 K promotes GR through NF-κB-induced CR and subsequently CR-dependent Cdc42 upregulation, where Cdc42 couples CR to GR. Taken together, HURP methylation statuses provide a unique opportunity to understand how GR is regulated, and the GA intrinsic mechanism controlling Golgi rigidity and the GA extrinsic mechanism involving NF-κB-CR-Cdc42 cascade collectively dictate GR.
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Affiliation(s)
| | - Shao-Chih Chiu
- Graduate Institute of Biomedical Sciences, China Medical University, Taichung, Taiwan.,Department of Medical Research, Translational Cell Therapy Center, China Medical University Hospital, Taichung, Taiwan
| | - Jeng-Sen Tseng
- Department of Internal Medicine, Division of Chest Medicine, Taichung Veterans General Hospital, Taichung, Taiwan.,Faculty of Medicine, National Yang-Ming University, Taipei, Taiwan.,Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan
| | - Jo-Mei Maureen Chen
- Department of Applied Chemistry, National Chi Nan University, Nantou, Taiwan.,Graduate Institute of Biomedical Sciences, China Medical University, Taichung, Taiwan
| | - Tong-You Wade Wei
- Department of Applied Chemistry, National Chi Nan University, Nantou, Taiwan.,Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan.,Department of Medicine, Postdoctoral Scholar, University of California, San Diego, California, USA
| | - Chen-Yu Chu
- Department of Applied Chemistry, National Chi Nan University, Nantou, Taiwan
| | - Hsu-Ting Eric Kao
- Department of Applied Chemistry, National Chi Nan University, Nantou, Taiwan
| | | | - Yong-Chun Erin Shih
- Department of Applied Chemistry, National Chi Nan University, Nantou, Taiwan
| | - Tsung-Ying Yang
- Department of Internal Medicine, Division of Chest Medicine, Taichung Veterans General Hospital, Taichung, Taiwan.,Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan
| | - Kun-Yuan Chiu
- Department of Applied Chemistry, National Chi Nan University, Nantou, Taiwan.,Department of Surgery, Division of Urology, Taichung Veterans General Hospital, Taichung, Taiwan
| | - Chieh-Lin Jerry Teng
- Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan.,Department of Medicine, Division of Hematology/Medical Oncology, Taichung Veterans General Hospital, Taichung, Taiwan.,School of Medicine, Chung Shan Medical University, Taichung, Taiwan
| | - Chang-Tze Ricky Yu
- Department of Applied Chemistry, National Chi Nan University, Nantou, Taiwan
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3
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Popova JV, Pavlova GA, Razuvaeva AV, Yarinich LA, Andreyeva EN, Anders AF, Galimova YA, Renda F, Somma MP, Pindyurin AV, Gatti M. Genetic Control of Kinetochore-Driven Microtubule Growth in Drosophila Mitosis. Cells 2022; 11:cells11142127. [PMID: 35883570 PMCID: PMC9323100 DOI: 10.3390/cells11142127] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 06/28/2022] [Accepted: 06/29/2022] [Indexed: 01/08/2023] Open
Abstract
Centrosome-containing cells assemble their spindles exploiting three main classes of microtubules (MTs): MTs nucleated by the centrosomes, MTs generated near the chromosomes/kinetochores, and MTs nucleated within the spindle by the augmin-dependent pathway. Mammalian and Drosophila cells lacking the centrosomes generate MTs at kinetochores and eventually form functional bipolar spindles. However, the mechanisms underlying kinetochore-driven MT formation are poorly understood. One of the ways to elucidate these mechanisms is the analysis of spindle reassembly following MT depolymerization. Here, we used an RNA interference (RNAi)-based reverse genetics approach to dissect the process of kinetochore-driven MT regrowth (KDMTR) after colcemid-induced MT depolymerization. This MT depolymerization procedure allows a clear assessment of KDMTR, as colcemid disrupts centrosome-driven MT regrowth but not KDMTR. We examined KDMTR in normal Drosophila S2 cells and in S2 cells subjected to RNAi against conserved genes involved in mitotic spindle assembly: mast/orbit/chb (CLASP1), mei-38 (TPX2), mars (HURP), dgt6 (HAUS6), Eb1 (MAPRE1/EB1), Patronin (CAMSAP2), asp (ASPM), and Klp10A (KIF2A). RNAi-mediated depletion of Mast/Orbit, Mei-38, Mars, Dgt6, and Eb1 caused a significant delay in KDMTR, while loss of Patronin had a milder negative effect on this process. In contrast, Asp or Klp10A deficiency increased the rate of KDMTR. These results coupled with the analysis of GFP-tagged proteins (Mast/Orbit, Mei-38, Mars, Eb1, Patronin, and Asp) localization during KDMTR suggested a model for kinetochore-dependent spindle reassembly. We propose that kinetochores capture the plus ends of MTs nucleated in their vicinity and that these MTs elongate at kinetochores through the action of Mast/Orbit. The Asp protein binds the MT minus ends since the beginning of KDMTR, preventing excessive and disorganized MT regrowth. Mei-38, Mars, Dgt6, Eb1, and Patronin positively regulate polymerization, bundling, and stabilization of regrowing MTs until a bipolar spindle is reformed.
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Affiliation(s)
- Julia V. Popova
- Institute of Molecular and Cellular Biology, Siberian Branch of Russian Academy of Sciences, 630090 Novosibirsk, Russia; (J.V.P.); (G.A.P.); (A.V.R.); (L.A.Y.); (E.N.A.); (A.F.A.); (Y.A.G.)
- Laboratory of Bioengineering, Novosibirsk State Agrarian University, 630039 Novosibirsk, Russia
| | - Gera A. Pavlova
- Institute of Molecular and Cellular Biology, Siberian Branch of Russian Academy of Sciences, 630090 Novosibirsk, Russia; (J.V.P.); (G.A.P.); (A.V.R.); (L.A.Y.); (E.N.A.); (A.F.A.); (Y.A.G.)
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Alyona V. Razuvaeva
- Institute of Molecular and Cellular Biology, Siberian Branch of Russian Academy of Sciences, 630090 Novosibirsk, Russia; (J.V.P.); (G.A.P.); (A.V.R.); (L.A.Y.); (E.N.A.); (A.F.A.); (Y.A.G.)
- Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, 630090 Novosibirsk, Russia
| | - Lyubov A. Yarinich
- Institute of Molecular and Cellular Biology, Siberian Branch of Russian Academy of Sciences, 630090 Novosibirsk, Russia; (J.V.P.); (G.A.P.); (A.V.R.); (L.A.Y.); (E.N.A.); (A.F.A.); (Y.A.G.)
- Faculty of Natural Sciences, Novosibirsk State University, 630090 Novosibirsk, Russia
| | - Evgeniya N. Andreyeva
- Institute of Molecular and Cellular Biology, Siberian Branch of Russian Academy of Sciences, 630090 Novosibirsk, Russia; (J.V.P.); (G.A.P.); (A.V.R.); (L.A.Y.); (E.N.A.); (A.F.A.); (Y.A.G.)
| | - Alina F. Anders
- Institute of Molecular and Cellular Biology, Siberian Branch of Russian Academy of Sciences, 630090 Novosibirsk, Russia; (J.V.P.); (G.A.P.); (A.V.R.); (L.A.Y.); (E.N.A.); (A.F.A.); (Y.A.G.)
| | - Yuliya A. Galimova
- Institute of Molecular and Cellular Biology, Siberian Branch of Russian Academy of Sciences, 630090 Novosibirsk, Russia; (J.V.P.); (G.A.P.); (A.V.R.); (L.A.Y.); (E.N.A.); (A.F.A.); (Y.A.G.)
| | - Fioranna Renda
- Institute of Molecular Biology and Pathology (IBPM), National Research Council (CNR), c/o Department of Biology and Biotechnology, Sapienza University of Rome, 00185 Rome, Italy; (F.R.); (M.P.S.)
| | - Maria Patrizia Somma
- Institute of Molecular Biology and Pathology (IBPM), National Research Council (CNR), c/o Department of Biology and Biotechnology, Sapienza University of Rome, 00185 Rome, Italy; (F.R.); (M.P.S.)
| | - Alexey V. Pindyurin
- Institute of Molecular and Cellular Biology, Siberian Branch of Russian Academy of Sciences, 630090 Novosibirsk, Russia; (J.V.P.); (G.A.P.); (A.V.R.); (L.A.Y.); (E.N.A.); (A.F.A.); (Y.A.G.)
- Correspondence: (A.V.P.); (M.G.)
| | - Maurizio Gatti
- Institute of Molecular and Cellular Biology, Siberian Branch of Russian Academy of Sciences, 630090 Novosibirsk, Russia; (J.V.P.); (G.A.P.); (A.V.R.); (L.A.Y.); (E.N.A.); (A.F.A.); (Y.A.G.)
- Institute of Molecular Biology and Pathology (IBPM), National Research Council (CNR), c/o Department of Biology and Biotechnology, Sapienza University of Rome, 00185 Rome, Italy; (F.R.); (M.P.S.)
- Correspondence: (A.V.P.); (M.G.)
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4
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Zhang H, Liu Y, Tang S, Qin X, Li L, Zhou J, Zhang J, Liu B. Knockdown of DLGAP5 suppresses cell proliferation, induces G 2/M phase arrest and apoptosis in ovarian cancer. Exp Ther Med 2021; 22:1245. [PMID: 34539841 PMCID: PMC8438692 DOI: 10.3892/etm.2021.10680] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 07/14/2021] [Indexed: 12/15/2022] Open
Abstract
Discs large-associated protein 5 (DLGAP5) is a microtubule-associated protein and is reported to exert oncogenic role in tumorigenesis, including lung cancer and hepatocellular carcinoma. However, the prognostic value and biological function of DLGAP5 in ovarian cancer (OC) still remain unclear. The present study investigated the expression pattern of DLGAP5 by searching the Oncomine microarray database. The correlation between DLGAP5 and survival prognosis of OC patients was analyzed by the online tool KM-plotter. Knockdown of DLGAP5 was achieved by transfection with small interfering RNA targeting DLGAP5 in two OC cell lines (SKOV3 and CAOV3). Cell proliferation was assessed by Cell Counting Kit-8 assay and colony-formation assay. Flow cytometry was utilized to determine the effects of DLGAP5 on cell cycle distribution and apoptosis. The present study data showed that DLGAP5 was significantly upregulated in OC and its higher expression was associated with poor survival prognosis. Knockdown of DLGAP5 significantly suppressed cell proliferation, induced cell cycle G2/M phase arrest and apoptosis. Western blot analysis further demonstrated that DLGAP5 knockdown downregulated the expression of CDK1, Cyclin B1 and Bcl-2, but upregulated Bax expression. Collectively, these data demonstrate that DLGAP5 might be a promising prognostic therapeutic target for OC treatment.
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Affiliation(s)
- Huijun Zhang
- Department of Obstetrics and Gynecology, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Xiangyang, Hubei 441000, P.R. China
| | - Yuan Liu
- Department of Oncology, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Xiangyang, Hubei 441000, P.R. China
| | - Shengchun Tang
- Department of Physical Examination, Xiangyang City Center for Disease Control and Prevention, Xiangyang, Hubei 441021, P.R. China
| | - Xiaomin Qin
- Department of Obstetrics and Gynecology, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Xiangyang, Hubei 441000, P.R. China
| | - Lin Li
- Department of Obstetrics and Gynecology, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Xiangyang, Hubei 441000, P.R. China
| | - Jinting Zhou
- Department of Obstetrics and Gynecology, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Xiangyang, Hubei 441000, P.R. China
| | - Jing Zhang
- Department of Obstetrics and Gynecology, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Xiangyang, Hubei 441000, P.R. China
| | - Bo Liu
- Department of Oncology, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Xiangyang, Hubei 441000, P.R. China
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5
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Chiu SC, Huang YRJ, Wei TYW, Chen JMM, Kuo YC, Huang YTJ, Liao YTA, Yu CTR. The PRMT5/HURP axis retards Golgi repositioning by stabilizing acetyl-tubulin and Golgi apparatus during cell migration. J Cell Physiol 2021; 237:1033-1043. [PMID: 34541678 DOI: 10.1002/jcp.30589] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 08/29/2021] [Accepted: 08/31/2021] [Indexed: 11/10/2022]
Abstract
The Golgi apparatus (GA) translocates to the cell leading end during directional migration, thereby determining cell polarity and transporting essential factors to the migration apparatus. The study provides mechanistic insights into how GA repositioning (GR) is regulated. We show that the methyltransferase PRMT5 methylates the microtubule regulator HURP at R122. The HURP methylation mimicking mutant 122F impairs GR and cell migration. Mechanistic studies revealed that HURP 122F or endogenous methylated HURP, that is, HURP m122, interacts with acetyl-tubulin. Overexpression of HURP 122F stabilizes the bundling pattern of acetyl-tubulin by decreasing the sensitivity of the latter to a microtubule disrupting agent nocodazole. HURP 122F also rigidifies GA via desensitizing the organelle to several GA disrupting chemicals. Similarly, the acetyl-tubulin mimicking mutant 40Q or tubulin acetyltransferase αTAT1 can rigidify GA, impair GR, and retard cell migration. Reversal of HURP 122F-induced GA rigidification, by knocking down GA assembly factors such as GRASP65 or GM130, attenuates 122F-triggered GR and cell migration. Remarkably, PRMT5 is found downregulated and the level of HURP m122 is decreased during the early hours of wound healing-based cell migration, collectively implying that the PRMT5-HURP-acetyl-tubulin axis plays the role of brake, preventing GR and cell migration before cells reach empty space.
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Affiliation(s)
- Shao-Chih Chiu
- Graduate Institute of Biomedical Sciences, China Medical University, Taichung, Taiwan.,Department of Medical Research, Translational Cell Therapy Center, China Medical University Hospital, Taichung, Taiwan
| | | | - Tong-You Wade Wei
- Graduate Institute of Biomedicine and Biomedical Technology, National Chi Nan University, Nantou, Taiwan.,Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Jo-Mei Maureen Chen
- Department of Applied Chemistry, National Chi Nan University, Nantou, Taiwan
| | - Yi-Chun Kuo
- Graduate Institute of Biomedicine and Biomedical Technology, National Chi Nan University, Nantou, Taiwan
| | - Yu-Ting Jenny Huang
- Department of Applied Chemistry, National Chi Nan University, Nantou, Taiwan
| | - Yu-Ting Amber Liao
- Department of Applied Chemistry, National Chi Nan University, Nantou, Taiwan
| | - Chang-Tze Ricky Yu
- Department of Applied Chemistry, National Chi Nan University, Nantou, Taiwan.,Graduate Institute of Biomedicine and Biomedical Technology, National Chi Nan University, Nantou, Taiwan
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6
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Barisic M, Rajendraprasad G, Steblyanko Y. The metaphase spindle at steady state - Mechanism and functions of microtubule poleward flux. Semin Cell Dev Biol 2021; 117:99-117. [PMID: 34053864 DOI: 10.1016/j.semcdb.2021.05.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 05/13/2021] [Accepted: 05/13/2021] [Indexed: 11/24/2022]
Abstract
The mitotic spindle is a bipolar cellular structure, built from tubulin polymers, called microtubules, and interacting proteins. This macromolecular machine orchestrates chromosome segregation, thereby ensuring accurate distribution of genetic material into the two daughter cells during cell division. Powered by GTP hydrolysis upon tubulin polymerization, the microtubule ends exhibit a metastable behavior known as the dynamic instability, during which they stochastically switch between the growth and shrinkage phases. In the context of the mitotic spindle, dynamic instability is furthermore regulated by microtubule-associated proteins and motor proteins, which enables the spindle to undergo profound changes during mitosis. This highly dynamic behavior is essential for chromosome capture and congression in prometaphase, as well as for chromosome alignment to the spindle equator in metaphase and their segregation in anaphase. In this review we focus on the mechanisms underlying microtubule dynamics and sliding and their importance for the maintenance of shape, structure and dynamics of the metaphase spindle. We discuss how these spindle properties are related to the phenomenon of microtubule poleward flux, highlighting its highly cooperative molecular basis and role in keeping the metaphase spindle at a steady state.
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Affiliation(s)
- Marin Barisic
- Cell Division and Cytoskeleton, Danish Cancer Society Research Center (DCRC), Strandboulevarden 49, 2100 Copenhagen, Denmark; Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark.
| | - Girish Rajendraprasad
- Cell Division and Cytoskeleton, Danish Cancer Society Research Center (DCRC), Strandboulevarden 49, 2100 Copenhagen, Denmark
| | - Yulia Steblyanko
- Cell Division and Cytoskeleton, Danish Cancer Society Research Center (DCRC), Strandboulevarden 49, 2100 Copenhagen, Denmark
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7
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Yamamoto S, Takayama KI, Obinata D, Fujiwara K, Ashikari D, Takahashi S, Inoue S. Identification of new octamer transcription factor 1-target genes upregulated in castration-resistant prostate cancer. Cancer Sci 2019; 110:3476-3485. [PMID: 31454442 PMCID: PMC6825001 DOI: 10.1111/cas.14183] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2019] [Revised: 08/18/2019] [Accepted: 08/25/2019] [Indexed: 12/12/2022] Open
Abstract
Octamer transcription factor 1 (OCT1) is an androgen receptor (AR)‐interacting partner and regulates the expression of target genes in prostate cancer cells. However, the function of OCT1 in castration‐resistant prostate cancer (CRPC) is not fully understood. In the present study, we used 22Rv1 cells as AR‐positive CRPC model cells to analyze the role of OCT1 in CRPC. We showed that OCT1 knockdown suppressed cell proliferation and migration of 22Rv1 cells. Using microarray analysis, we identified four AR and OCT1‐target genes, disks large‐associated protein 5 (DLGAP5), kinesin family member 15 (KIF15), non‐SMC condensin I complex subunit G (NCAPG), and NDC80 kinetochore complex component (NUF2) in 22Rv1 cells. We observed that knockdown of DLGAP5 and NUF2 suppresses growth and migration of 22Rv1 cells. Furthermore, immunohistochemical analysis showed that positive expression of DLGAP5 in prostate cancer specimens is related to poor cancer‐specific survival rates of patients. Notably, enhanced expression of DLGAP5 was observed in CRPC tissues of patients. Thus, our findings suggest that these four genes regulated by the AR/OCT1 complex could have an important role in CRPC progression.
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Affiliation(s)
- Shinichiro Yamamoto
- Department of Systems Aging Science and Medicine, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan.,Department of Urology, Nihon University School of Medicine, Tokyo, Japan
| | - Ken-Ichi Takayama
- Department of Systems Aging Science and Medicine, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
| | - Daisuke Obinata
- Department of Urology, Nihon University School of Medicine, Tokyo, Japan
| | - Kyoko Fujiwara
- Department of Medicine, Nihon University School of Medicine, Tokyo, Japan.,Department of Anatomy, Nihon University School of Dentistry, Tokyo, Japan
| | - Daisaku Ashikari
- Department of Urology, Nihon University School of Medicine, Tokyo, Japan
| | - Satoru Takahashi
- Department of Urology, Nihon University School of Medicine, Tokyo, Japan
| | - Satoshi Inoue
- Department of Systems Aging Science and Medicine, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan.,Division of Gene Regulation and Signal Transduction, Research Center for Genomic Medicine, Saitama Medical University, Tokyo, Japan
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8
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Hewit K, Sandilands E, Martinez RS, James D, Leung HY, Bryant DM, Shanks E, Markert EK. A functional genomics screen reveals a strong synergistic effect between docetaxel and the mitotic gene DLGAP5 that is mediated by the androgen receptor. Cell Death Dis 2018; 9:1069. [PMID: 30341281 PMCID: PMC6195526 DOI: 10.1038/s41419-018-1115-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2018] [Revised: 09/10/2018] [Accepted: 09/12/2018] [Indexed: 01/31/2023]
Abstract
Based on a molecular classification of prostate cancer using gene expression pathway signatures, we derived a set of 48 genes in critical pathways that significantly predicts clinical outcome in all tested patient cohorts. We tested these genes in a functional genomics screen in a panel of three prostate cancer cell lines (LNCaP, PC3, DU145), using RNA interference. The screen revealed several genes whose knockdown caused strong growth inhibition in all cell lines. Additionally, we tested the gene set in the presence of docetaxel to see whether any gene exhibited additive or synergistic effects with the drug. We observed a strong synergistic effect between DLGAP5 knockdown and docetaxel in the androgen-sensitive line LNCaP, but not in the two other androgen-independent lines. We then tested whether this effect was connected to androgen pathways and found that knockdown of the androgen receptor by si-RNA attenuated the synergy significantly. Similarly, androgen desensitized LNCaP-AI cells had a higher IC50 to docetaxel and did not exhibit the synergistic interaction. Short-term exposure to enzalutamide did not significantly alter the behaviour of parental LNCaP cells. An immunofluorescence analysis in LNCaP cells suggests that under the double insult of DLGAP5 knockdown and docetaxel, cells predominantly arrest in metaphase. In contrast, the knockdown of the androgen receptor by siRNA appears to assist cells to progress through metaphase in to anaphase, even in the presence of docetaxel. Our data suggest that DLGAP5 has a unique function in stabilizing spindle formation and surviving microtubule assault from docetaxel, in an androgen-regulated cell cycle system.
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Affiliation(s)
- Kay Hewit
- Institute of Cancer Sciences, University of Glasgow, Glasgow, UK
- Scottish National Blood Transfusion Service, NSS, Glasgow, UK
| | - Emma Sandilands
- Institute of Cancer Sciences, University of Glasgow, Glasgow, UK
- Cancer Research UK Beatson Institute, Glasgow, UK
| | | | - Daniel James
- Cancer Research UK Beatson Institute, Glasgow, UK
| | - Hing Y Leung
- Institute of Cancer Sciences, University of Glasgow, Glasgow, UK
- Cancer Research UK Beatson Institute, Glasgow, UK
| | - David M Bryant
- Institute of Cancer Sciences, University of Glasgow, Glasgow, UK
- Cancer Research UK Beatson Institute, Glasgow, UK
| | - Emma Shanks
- Cancer Research UK Beatson Institute, Glasgow, UK
| | - Elke K Markert
- Institute of Cancer Sciences, University of Glasgow, Glasgow, UK.
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9
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Wang Q, Chen Y, Feng H, Zhang B, Wang H. Prognostic and predictive value of HURP in non‑small cell lung cancer. Oncol Rep 2018; 39:1682-1692. [PMID: 29484418 PMCID: PMC5868404 DOI: 10.3892/or.2018.6280] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 02/09/2018] [Indexed: 02/07/2023] Open
Abstract
Previous studies have revealed that HURP (also known as DLGAP5 or KIAA0008) is overexpressed in many types of human cancers, such as hepatocellular carcinoma, squamous cell bladder cancer, and transitional cell carcinoma, indicating that HURP is a putative oncoprotein that promotes carcinogenesis through various molecular mechanisms. However, the role of HURP in the pathogenesis of non-small cell lung cancer (NSCLC) has not been reported. In the present study, we investigated the prognostic value of HURP among NSCLC patients through the GEO database. The online tool of KM-plotter was used to identify the correlation of HURP expression and the survival of NSCLC patients. We found the HURP expression at the mRNA level was correlated with the clinicopathologic characteristics and prognosis of NSCLC patients. HURP was highly expressed in aggressive NSCLC cells, and its higher expression was associated with shorter survival. Further cytological experiments revealed that the silencing of HURP caused cell cycle arrest and inhibited the proliferation of NSCLC cells. Transwell assay showed that HURP shRNA inhibited cell migration and invasion in vitro. The bioinformatic analysis suggests that HURP promotes carcinogenesis in multiple manners. Taken together, we revealed the prognostic value of HURP in NSCLC patients and HURP may be a potential therapeutic target for NSCLC.
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Affiliation(s)
- Qi Wang
- Department of Oncology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266000, P.R. China
| | - Yaokun Chen
- Breast Disease Diagnosis and Treatment Center, Qingdao Center Medical Group, Qingdao, Shandong 266000, P.R. China
| | - Hui Feng
- Department of Oncology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266000, P.R. China
| | - Biyuan Zhang
- Department of Oncology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266000, P.R. China
| | - Haiji Wang
- Department of Oncology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266000, P.R. China
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10
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Sulimenko V, Hájková Z, Klebanovych A, Dráber P. Regulation of microtubule nucleation mediated by γ-tubulin complexes. PROTOPLASMA 2017; 254:1187-1199. [PMID: 28074286 DOI: 10.1007/s00709-016-1070-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 12/22/2016] [Indexed: 05/18/2023]
Abstract
The microtubule cytoskeleton is critically important for spatio-temporal organization of eukaryotic cells. The nucleation of new microtubules is typically restricted to microtubule organizing centers (MTOCs) and requires γ-tubulin that assembles into multisubunit complexes of various sizes. γ-Tubulin ring complexes (TuRCs) are efficient microtubule nucleators and are associated with large number of targeting, activating and modulating proteins. γ-Tubulin-dependent nucleation of microtubules occurs both from canonical MTOCs, such as spindle pole bodies and centrosomes, and additional sites such as Golgi apparatus, nuclear envelope, plasma membrane-associated sites, chromatin and surface of pre-existing microtubules. Despite many advances in structure of γ-tubulin complexes and characterization of γTuRC interacting factors, regulatory mechanisms of microtubule nucleation are not fully understood. Here, we review recent work on the factors and regulatory mechanisms that are involved in centrosomal and non-centrosomal microtubule nucleation.
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Affiliation(s)
- Vadym Sulimenko
- Department of Biology of Cytoskeleton, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Vídeňská 1083, 142 20, Prague 4, Czech Republic
| | - Zuzana Hájková
- Department of Biology of Cytoskeleton, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Vídeňská 1083, 142 20, Prague 4, Czech Republic
| | - Anastasiya Klebanovych
- Department of Biology of Cytoskeleton, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Vídeňská 1083, 142 20, Prague 4, Czech Republic
| | - Pavel Dráber
- Department of Biology of Cytoskeleton, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Vídeňská 1083, 142 20, Prague 4, Czech Republic.
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11
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Yokoyama H, Koch B, Walczak R, Ciray-Duygu F, González-Sánchez JC, Devos DP, Mattaj IW, Gruss OJ. The nucleoporin MEL-28 promotes RanGTP-dependent γ-tubulin recruitment and microtubule nucleation in mitotic spindle formation. Nat Commun 2015; 5:3270. [PMID: 24509916 DOI: 10.1038/ncomms4270] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Accepted: 01/16/2014] [Indexed: 01/11/2023] Open
Abstract
The GTP-bound form of the Ran GTPase (RanGTP), produced around chromosomes, drives nuclear envelope and nuclear pore complex (NPC) re-assembly after mitosis. The nucleoporin MEL-28/ELYS binds chromatin in a RanGTP-regulated manner and acts to seed NPC assembly. Here we show that, upon mitotic NPC disassembly, MEL-28 dissociates from chromatin and re-localizes to spindle microtubules and kinetochores. MEL-28 directly binds microtubules in a RanGTP-regulated way via its C-terminal chromatin-binding domain. Using Xenopus egg extracts, we demonstrate that MEL-28 is essential for RanGTP-dependent microtubule nucleation and spindle assembly, independent of its function in NPC assembly. Specifically, MEL-28 interacts with the γ-tubulin ring complex and recruits it to microtubule nucleation sites. Our data identify MEL-28 as a RanGTP target that functions throughout the cell cycle. Its cell cycle-dependent binding to chromatin or microtubules discriminates MEL-28 functions in interphase and mitosis, and ensures that spindle assembly occurs only after NPC breakdown.
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Affiliation(s)
- Hideki Yokoyama
- 1] Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany [2] European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Birgit Koch
- European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Rudolf Walczak
- European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Fulya Ciray-Duygu
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany
| | | | - Damien P Devos
- Centre for Organismal Studies (COS), Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
| | - Iain W Mattaj
- European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Oliver J Gruss
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany
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12
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Yount AL, Zong H, Walczak CE. Regulatory mechanisms that control mitotic kinesins. Exp Cell Res 2015; 334:70-7. [PMID: 25576382 DOI: 10.1016/j.yexcr.2014.12.015] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Accepted: 12/26/2014] [Indexed: 11/18/2022]
Abstract
During mitosis, the mitotic spindle is assembled to align chromosomes at the spindle equator in metaphase, and to separate the genetic material equally to daughter cells in anaphase. The spindle itself is a macromolecular machine composed of an array of dynamic microtubules and associated proteins that coordinate the diverse events of mitosis. Among the microtubule associated proteins are a plethora of molecular motor proteins that couple the energy of ATP hydrolysis to force production. These motors, including members of the kinesin superfamily, must function at the right time and in the right place to insure the fidelity of mitosis. Misregulation of mitotic motors in disease states, such as cancer, underlies their potential utility as targets for antitumor drug development and highlights the importance of understanding the molecular mechanisms for regulating their function. Here, we focus on recent progress about regulatory mechanisms that control the proper function of mitotic kinesins and highlight new findings that lay the path for future studies.
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Affiliation(s)
- Amber L Yount
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, United States
| | - Hailing Zong
- Department of Biology, Indiana University, Bloomington, IN 47405, United States
| | - Claire E Walczak
- Medical Sciences, Indiana University, Myers Hall 262, 915 East 3rd Street, Bloomington, IN 47405, United States.
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13
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Chen JMM, Chiu SC, Wei TYW, Lin SY, Chong CM, Wu CC, Huang JY, Yang ST, Ku CF, Hsia JY, Yu CTR. The involvement of nuclear factor-κappaB in the nuclear targeting and cyclin E1 upregulating activities of hepatoma upregulated protein. Cell Signal 2014; 27:26-36. [PMID: 25289861 DOI: 10.1016/j.cellsig.2014.09.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Revised: 09/12/2014] [Accepted: 09/23/2014] [Indexed: 11/28/2022]
Abstract
Hepatoma upregulated protein (HURP) is originally isolated during the search for the genes associated with hepatoma. HURP is upregulated in many human cancers. Culture cells exhibit transformed and invasive phenotype when ectopic HURP is introduced, revealing HURP as an oncogene candidate. Our previous studies demonstrated that Aurora-A regulated the cell transforming activities of HURP by phosphorylating HURP at four serines. To unravel how the Aurora-A/HURP cascade contributes to cell transformation, we firstly noticed that HURP shuttled between cytoplasm and nucleus. The nuclear localization activity of HURP was promoted or abolished by overexpression or knockdown of Aurora-A. Similarly, the HURP phosphorylation mimicking mutant 4E had higher nuclear targeting activity than the phosphorylation deficient mutant 4A. The HURP 4E accelerated G1 progression and upregulated cyclin E1, and the cyclin E1 upregulating and cell transforming activities of HURP were diminished when the nuclear localization signal (NLS) was removed from HURP. Furthermore, HURP employed p38/nuclear factor-κB (NF-κB) cascade to stimulate cell growth. Interestingly, NF-κB trapped HURP in nucleus by interacting with HURP 4E. At last, the HURP/NF-κB complex activated the cyclin E1 promoter. Collectively, Aurora-A/HURP relays cell transforming signal to NF-κB, and the HURP/NF-κB complex is engaged in the regulation of cyclin E1 expression.
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Affiliation(s)
- Jo-Mei Maureen Chen
- Graduate Institute of Biomedicine and Biomedical Technology, National Chi Nan University, Taiwan
| | - Shao-Chih Chiu
- Graduate Institute of Immunology, China Medical University, Taichung, Taiwan; Center for Neuropsychiatry, China Medical University Hospital, Taichung, Taiwan
| | - Tong-You Wade Wei
- Department of Applied Chemistry, National Chi Nan University, Taiwan
| | - Shin-Yi Lin
- Department of Applied Chemistry, National Chi Nan University, Taiwan
| | - Cheong-Meng Chong
- Department of Applied Chemistry, National Chi Nan University, Taiwan
| | - Chi-Chen Wu
- Graduate Institute of Biomedicine and Biomedical Technology, National Chi Nan University, Taiwan
| | - Jiao-Ying Huang
- Graduate Institute of Biomedicine and Biomedical Technology, National Chi Nan University, Taiwan
| | - Shu-Ting Yang
- Graduate Institute of Biomedicine and Biomedical Technology, National Chi Nan University, Taiwan
| | - Chia-Feng Ku
- Department of Applied Chemistry, National Chi Nan University, Taiwan
| | - Jiun-Yi Hsia
- Department of Surgery, Taichung Veterans General Hospital, Taichung, Taiwan
| | - Chang-Tze Ricky Yu
- Graduate Institute of Biomedicine and Biomedical Technology, National Chi Nan University, Taiwan; Department of Applied Chemistry, National Chi Nan University, Taiwan.
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14
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Staiber W. GTPase Ran strongly accumulates at the kinetochores of somatic chromosomes in the spermatogonial mitoses of Acricotopus lucidus (Diptera, Chironomidae). PROTOPLASMA 2014; 251:979-984. [PMID: 24240516 DOI: 10.1007/s00709-013-0578-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Accepted: 10/28/2013] [Indexed: 06/02/2023]
Abstract
Unequal chromosome segregation and spindle formation occurs in the last gonial mitosis in the germ line of the chironomid Acricotopus lucidus. During this differential mitosis, all germ line-limited chromosomes (=Ks) migrate undivided to only one pole of the cell, while the somatic chromosomes (=Ss) first remain in the metaphase plane, and with the arrival of the Ks at the pole, they then separate equally. The evolutionarily conserved GTPase Ran plays a crucial role in many cellular processes. This includes the regulation of microtubule nucleation and stabilisation at kinetochores and of spindle assembly during mitosis, which is promoted by a RanGTP concentration gradient that forms around the mitotic chromosomes (Kalab et al. in Science 295:2452-2456, 2002, Nature 440:697-701, 2006). In the present study, a strong accumulation of Ran was detected by immunofluorescence at the kinetochores of the Ss in normal gonial and differential gonial mitoses of males of A. lucidus. In contrast, no Ran accumulation was observed at the kinetochores of the Ss in the metaphases of brain ganglia mitoses or of aberrant spermatocytes or in metaphases I and II of spermatocyte meiotic divisions. Likewise, there was no accumulation at the kinetochores of Drosophila melanogaster mitotic chromosomes from larval brains. The specific accumulation of Ran at the kinetochores of the Ss in differential gonial mitoses of A. lucidus strongly suggests that Ran is involved in a mechanism acting in this exceptional mitosis, which retains the Ss at the metaphase plane and prevents a premature separation and unequal segregation of the Ss during monopolar migration of the Ks.
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Affiliation(s)
- Wolfgang Staiber
- Institute of Genetics (240), University of Hohenheim, Garbenstrasse 30, 70599, Stuttgart, Germany,
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15
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Bakhoum SF, Compton DA. Kinetochores and disease: keeping microtubule dynamics in check! Curr Opin Cell Biol 2011; 24:64-70. [PMID: 22196931 DOI: 10.1016/j.ceb.2011.11.012] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Revised: 11/21/2011] [Accepted: 11/28/2011] [Indexed: 12/12/2022]
Abstract
The essential role of microtubules in cell division has long been known. Yet the mechanism by which microtubule attachment to chromosomes at kinetochores is regulated has only been recently revealed. Here, we review the role of kinetochore-microtubule (kMT) attachment dynamics in the cell cycle as well as emerging evidence linking deregulation of kMT attachments to diseases where chromosome mis-segregation and aneuploidy play a central role. Evidence indicates that the dynamic behavior of kMTs must fall within narrow permissible boundaries, which simultaneously allow a level of stability sufficient to establish and maintain chromosome-microtubule attachments and a degree of instability that permits error correction required for accurate chromosome segregation.
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Affiliation(s)
- Samuel F Bakhoum
- Department of Biochemistry, Dartmouth Medical School, Hanover, NH 03755, USA
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16
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Duncan T, Wakefield JG. 50 ways to build a spindle: the complexity of microtubule generation during mitosis. Chromosome Res 2011; 19:321-33. [PMID: 21484448 DOI: 10.1007/s10577-011-9205-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The accurate segregation of duplicated chromosomes, essential for the development and viability of a eukaryotic organism, requires the formation of a robust microtubule (MT)-based spindle apparatus. Entry into mitosis or meiosis precipitates a cascade of signalling events which result in the activation of pathways responsible for a dramatic reorganisation of the MT cytoskeleton: through changes in the properties of MT-associated proteins, local concentrations of free tubulin dimer and through enhanced MT nucleation. The latter is generally thought to be driven by localisation and activation of γ-tubulin-containing complexes (γ-TuSC and γ-TuRC) at specific subcellular locations. For example, upon entering mitosis, animal cells concentrate γ-tubulin at centrosomes to tenfold the normal level during interphase, resulting in an aster-driven search and capture of chromosomes and bipolar mitotic spindle formation. Thus, in these cells, centrosomes have traditionally been perceived as the primary microtubule organising centre during spindle formation. However, studies in meiotic cells, plants and cell-free extracts have revealed the existence of complementary mechanisms of spindle formation, mitotic chromatin, kinetochores and nucleation from existing MTs or the cytoplasm can all contribute to a bipolar spindle apparatus. Here, we outline the individual known mechanisms responsible for spindle formation and formulate ideas regarding the relationship between them in assembling a functional spindle apparatus.
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Affiliation(s)
- Tommy Duncan
- Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK
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17
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Groen AC, Coughlin M, Mitchison TJ. Microtubule assembly in meiotic extract requires glycogen. Mol Biol Cell 2011; 22:3139-51. [PMID: 21737678 PMCID: PMC3164461 DOI: 10.1091/mbc.e11-02-0158] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
We identified a clarified extract containing the soluble factors for microtubule assembly. We found that microtubule assembly does not require ribosomes, mitochondria, or membranes. Our clarified extracts will provide a powerful tool for activity-based biochemical fractionations for microtubule assembly. The assembly of microtubules during mitosis requires many identified components, such as γ-tubulin ring complex (γ-TuRC), components of the Ran pathway (e.g., TPX2, HuRP, and Rae1), and XMAP215/chTOG. However, it is far from clear how these factors function together or whether more factors exist. In this study, we used biochemistry to attempt to identify active microtubule nucleation protein complexes from Xenopus meiotic egg extracts. Unexpectedly, we found both microtubule assembly and bipolar spindle assembly required glycogen, which acted both as a crowding agent and as metabolic source glucose. By also reconstituting microtubule assembly in clarified extracts, we showed microtubule assembly does not require ribosomes, mitochondria, or membranes. Our clarified extracts will provide a powerful tool for activity-based biochemical fractionations for microtubule assembly.
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Affiliation(s)
- Aaron C Groen
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA.
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18
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Mottier-Pavie V, Cenci G, Vernì F, Gatti M, Bonaccorsi S. Phenotypic analysis of misato function reveals roles of noncentrosomal microtubules in Drosophila spindle formation. J Cell Sci 2011; 124:706-17. [PMID: 21285248 DOI: 10.1242/jcs.072348] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Mitotic spindle assembly in centrosome-containing cells relies on two main microtubule (MT) nucleation pathways, one based on centrosomes and the other on chromosomes. However, the relative role of these pathways is not well defined. In Drosophila, mutants without centrosomes can form functional anastral spindles and survive to adulthood. Here we show that mutations in the Drosophila misato (mst) gene inhibit kinetochore-driven MT growth, lead to the formation of monopolar spindles and cause larval lethality. In most prophase cells of mst mutant brains, asters are well separated, but collapse with progression of mitosis, suggesting that k-fibers are essential for maintenance of aster separation and spindle bipolarity. Analysis of mst; Sas-4 double mutants showed that mitotic cells lacking both the centrosomes and the mst function form polarized MT arrays that resemble monopolar spindles. MT regrowth experiments after cold exposure revealed that in mst; Sas-4 metaphase cells MTs regrow from several sites, which eventually coalesce to form a single polarized MT array. By contrast, in Sas-4 single mutants, chromosome-driven MT regrowth mostly produced robust bipolar spindles. Collectively, these results indicate that kinetochore-driven MT formation is an essential process for proper spindle assembly in Drosophila somatic cells.
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Affiliation(s)
- Violaine Mottier-Pavie
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Genetica e Biologia Molecolare, Sapienza Università di Roma, Ple. A. Moro 5, 00185 Roma, Italy
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19
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Vanden Bosch A, Raemaekers T, Denayer S, Torrekens S, Smets N, Moermans K, Dewerchin M, Carmeliet P, Carmeliet G. NuSAP is essential for chromatin-induced spindle formation during early embryogenesis. J Cell Sci 2010; 123:3244-55. [DOI: 10.1242/jcs.063875] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Mitotic spindle assembly is mediated by two processes: a centrosomal and a chromosomal pathway. RanGTP regulates the latter process by releasing microtubule-associated proteins from inhibitory complexes. NuSAP, a microtubule- and DNA-binding protein, is a target of RanGTP and promotes the formation of microtubules near chromosomes. However, the contribution of NuSAP to cell proliferation in vivo is unknown. Here, we demonstrate that the expression of NuSAP highly correlates with cell proliferation during embryogenesis and adult life, making it a reliable marker of proliferating cells. Additionally, we show that NuSAP deficiency in mice leads to early embryonic lethality. Spindle assembly in NuSAP-deficient cells is highly inefficient and chromosomes remain dispersed in the mitotic cytoplasm. As a result of sustained spindle checkpoint activity, the cells are unable to progress through mitosis, eventually leading to caspase activation and apoptotic cell death. Together, our findings demonstrate that NuSAP is essential for proliferation of embryonic cells and, simultaneously, they underscore the importance of chromatin-induced spindle assembly.
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Affiliation(s)
- An Vanden Bosch
- Laboratory of Experimental Medicine and Endocrinology, Katholieke Universiteit Leuven, 3000 Leuven, Belgium
| | - Tim Raemaekers
- Laboratory of Membrane Trafficking, Katholieke Universiteit Leuven, 3000 Leuven, Belgium
| | - Sarah Denayer
- Laboratory of Molecular Endocrinology, Katholieke Universiteit Leuven, 3000 Leuven, Belgium
| | - Sophie Torrekens
- Laboratory of Experimental Medicine and Endocrinology, Katholieke Universiteit Leuven, 3000 Leuven, Belgium
| | - Nico Smets
- Laboratory of Experimental Medicine and Endocrinology, Katholieke Universiteit Leuven, 3000 Leuven, Belgium
| | - Karen Moermans
- Laboratory of Experimental Medicine and Endocrinology, Katholieke Universiteit Leuven, 3000 Leuven, Belgium
| | - Mieke Dewerchin
- Vesalius Research Center (VRC), Katholieke Universiteit Leuven, 3000 Leuven, Belgium
- Vesalius Research Center (VRC), VIB, B-3000 Leuven, Belgium
| | - Peter Carmeliet
- Vesalius Research Center (VRC), Katholieke Universiteit Leuven, 3000 Leuven, Belgium
- Vesalius Research Center (VRC), VIB, B-3000 Leuven, Belgium
| | - Geert Carmeliet
- Laboratory of Experimental Medicine and Endocrinology, Katholieke Universiteit Leuven, 3000 Leuven, Belgium
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20
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Cross MK, Powers MA. Learning about cancer from frogs: analysis of mitotic spindles in Xenopus egg extracts. Dis Model Mech 2010; 2:541-7. [PMID: 19892884 DOI: 10.1242/dmm.002022] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The mitotic spindle is responsible for correctly segregating chromosomes during cellular division. Disruption of this process leads to genomic instability in the form of aneuploidy, which can contribute to the development of cancer. Therefore, identification and characterization of factors that are responsible for the assembly and regulation of the spindle are crucial. Not only are these factors often altered in cancer, but they also serve as potential therapeutic targets. Xenopus egg extract is a powerful tool for studying spindle assembly and other cell cycle-related events owing, in large part, to the ease with which protein function can be manipulated in the extract. Importantly, the spindle factors that have been characterized in egg extract are conserved in human spindle assembly. In this review, we explain how the extract is prepared and manipulated to study the function of individual factors in spindle assembly and the spindle checkpoint. Furthermore, we provide examples of several spindle factors that have been defined functionally using the extract system and discuss how these factors are altered in human cancer.
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Affiliation(s)
- Marie K Cross
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
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21
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Groen AC, Maresca TJ, Gatlin JC, Salmon ED, Mitchison TJ. Functional overlap of microtubule assembly factors in chromatin-promoted spindle assembly. Mol Biol Cell 2009; 20:2766-73. [PMID: 19369413 DOI: 10.1091/mbc.e09-01-0043] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Distinct pathways from centrosomes and chromatin are thought to contribute in parallel to microtubule nucleation and stabilization during animal cell mitotic spindle assembly, but their full mechanisms are not known. We investigated the function of three proposed nucleation/stabilization factors, TPX2, gamma-tubulin and XMAP215, in chromatin-promoted assembly of anastral spindles in Xenopus laevis egg extract. In addition to conventional depletion-add back experiments, we tested whether factors could substitute for each other, indicative of functional redundancy. All three factors were required for microtubule polymerization and bipolar spindle assembly around chromatin beads. Depletion of TPX2 was partially rescued by the addition of excess XMAP215 or EB1, or inhibiting MCAK (a Kinesin-13). Depletion of either gamma-tubulin or XMAP215 was partially rescued by adding back XMAP215, but not by adding any of the other factors. These data reveal functional redundancy between specific assembly factors in the chromatin pathway, suggesting individual proteins or pathways commonly viewed to be essential may not have entirely unique functions.
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Affiliation(s)
- Aaron C Groen
- Systems Biology Department, Harvard Medical School, Boston, MA 02445, USA.
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22
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Rizk RS, Bohannon KP, Wetzel LA, Powers J, Shaw SL, Walczak CE. MCAK and paclitaxel have differential effects on spindle microtubule organization and dynamics. Mol Biol Cell 2009; 20:1639-51. [PMID: 19158381 DOI: 10.1091/mbc.e08-09-0985] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Within the mitotic spindle, there are multiple populations of microtubules with different turnover dynamics, but how these different dynamics are maintained is not fully understood. MCAK is a member of the kinesin-13 family of microtubule-destabilizing enzymes that is required for proper establishment and maintenance of the spindle. Using quantitative immunofluorescence and fluorescence recovery after photobleaching, we compared the differences in spindle organization caused by global suppression of microtubule dynamics, by treating cells with low levels of paclitaxel, versus specific perturbation of spindle microtubule subsets by MCAK inhibition. Paclitaxel treatment caused a disruption in spindle microtubule organization marked by a significant increase in microtubules near the poles and a reduction in K-fiber fluorescence intensity. This was correlated with a faster t(1/2) of both spindle and K-fiber microtubules. In contrast, MCAK inhibition caused a dramatic reorganization of spindle microtubules with a significant increase in astral microtubules and reduction in K-fiber fluorescence intensity, which correlated with a slower t(1/2) of K-fibers but no change in the t(1/2) of spindle microtubules. Our data support the model that MCAK perturbs spindle organization by acting preferentially on a subset of microtubules, and they support the overall hypothesis that microtubule dynamics is differentially regulated in the spindle.
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Affiliation(s)
- Rania S Rizk
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
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