1
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Taha MS, Ahmadian MR. Nucleophosmin: A Nucleolar Phosphoprotein Orchestrating Cellular Stress Responses. Cells 2024; 13:1266. [PMID: 39120297 PMCID: PMC11312075 DOI: 10.3390/cells13151266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2024] [Revised: 07/18/2024] [Accepted: 07/24/2024] [Indexed: 08/10/2024] Open
Abstract
Nucleophosmin (NPM1) is a key nucleolar protein released from the nucleolus in response to stress stimuli. NPM1 functions as a stress regulator with nucleic acid and protein chaperone activities, rapidly shuttling between the nucleus and cytoplasm. NPM1 is ubiquitously expressed in tissues and can be found in the nucleolus, nucleoplasm, cytoplasm, and extracellular environment. It plays a central role in various biological processes such as ribosome biogenesis, cell cycle regulation, cell proliferation, DNA damage repair, and apoptosis. In addition, it is highly expressed in cancer cells and solid tumors, and its mutation is a major cause of acute myeloid leukemia (AML). This review focuses on NPM1's structural features, functional diversity, subcellular distribution, and role in stress modulation.
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Affiliation(s)
- Mohamed S. Taha
- Institute of Biochemistry and Molecular Biology II, Medical Faculty, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany
- Research on Children with Special Needs Department, Institute of Medical Research and Clinical Studies, National Research Centre, Cairo 12622, Egypt
| | - Mohammad Reza Ahmadian
- Institute of Biochemistry and Molecular Biology II, Medical Faculty, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany
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2
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Zimyanin V, Magaj M, Yu CH, Gibney T, Mustafa B, Horton X, Siller K, Cueff L, Bouvrais H, Pécréaux J, Needleman D, Redemann S. Lack of chromokinesin Klp-19 creates a more rigid midzone and affects force transmission during anaphase in C. elegans. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.26.564275. [PMID: 37961478 PMCID: PMC10634869 DOI: 10.1101/2023.10.26.564275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Recent studies have highlighted the significance of the spindle midzone - the region positioned between chromosomes - in ensuring proper chromosome segregation. By combining advanced 3D electron tomography and cutting-edge light microscopy we have discovered a previously unknown role of the regulation of microtubule dynamics within the spindle midzone of C. elegans. Using Fluorescence recovery after photobleaching and a combination of second harmonic generation and two-photon fluorescence microscopy, we found that the length of the antiparallel microtubule overlap zone in the spindle midzone is constant throughout anaphase, and independent of cortical pulling forces as well as the presence of the microtubule bundling protein SPD-1. Further investigations of SPD-1 and the chromokinesin KLP-19 in C. elegans suggest that KLP-19 regulates the overlap length and functions independently of SPD-1. Our data shows that KLP-19 plays an active role in regulating the length and turn-over of microtubules within the midzone as well as the size of the antiparallel overlap region throughout mitosis. Depletion of KLP-19 in mitosis leads to an increase in microtubule length in the spindle midzone, which also leads to increased microtubule - microtubule interaction, thus building up a more robust microtubule network. The spindle is globally stiffer and more stable, which has implications for the transmission of forces within the spindle affecting chromosome segregation dynamics. Our data shows that by localizing KLP-19 to the spindle midzone in anaphase microtubule dynamics can be locally controlled allowing the formation of a functional midzone.
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Affiliation(s)
- Vitaly Zimyanin
- Department of Molecular Physiology and Biological Physics, University of Virginia, School of Medicine, Charlottesville, VA, USA
- Center for Membrane and Cell Physiology, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Magdalena Magaj
- Department of Molecular Physiology and Biological Physics, University of Virginia, School of Medicine, Charlottesville, VA, USA
- Department of Cell Biology, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Che-Hang Yu
- Department of Electrical and Computer Engineering, University of California, Santa Barbara, CA, USA
| | - Theresa Gibney
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Basaran Mustafa
- Molecular and Cellular Biology and School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - Xavier Horton
- Department of Molecular Physiology and Biological Physics, University of Virginia, School of Medicine, Charlottesville, VA, USA
- Department of Cell Biology, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Karsten Siller
- IT-Research Computing, University of Virginia, Charlottesville, VA, USA
| | - Louis Cueff
- CNRS, Univ Rennes, IGDR (Institut de Génétique et Dévelopement de Rennes) - UMR 6290, F-35000 Rennes, France
| | - Hélène Bouvrais
- CNRS, Univ Rennes, IGDR (Institut de Génétique et Dévelopement de Rennes) - UMR 6290, F-35000 Rennes, France
| | - Jacques Pécréaux
- CNRS, Univ Rennes, IGDR (Institut de Génétique et Dévelopement de Rennes) - UMR 6290, F-35000 Rennes, France
| | - Daniel Needleman
- Molecular and Cellular Biology and School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
- Center for Computational Biology, Flatiron Institute, New York, NY, USA
| | - Stefanie Redemann
- Department of Molecular Physiology and Biological Physics, University of Virginia, School of Medicine, Charlottesville, VA, USA
- Center for Membrane and Cell Physiology, University of Virginia School of Medicine, Charlottesville, VA, USA
- Department of Cell Biology, University of Virginia School of Medicine, Charlottesville, VA, USA
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3
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Kraus J, Travis SM, King MR, Petry S. Augmin is a Ran-regulated spindle assembly factor. J Biol Chem 2023; 299:104736. [PMID: 37086784 DOI: 10.1016/j.jbc.2023.104736] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 04/03/2023] [Accepted: 04/05/2023] [Indexed: 04/24/2023] Open
Abstract
Mitotic spindles are composed of microtubules (MTs) that must nucleate at the right place and time. Ran regulates this process by directly controlling the release of spindle assembly factors (SAFs) from nucleocytoplasmic shuttle proteins importin-αβ and subsequently forms a biochemical gradient of SAFs localized around chromosomes. The majority of spindle MTs are generated by branching MT nucleation, which has been shown to require an eight-subunit protein complex known as augmin. InXenopus laevis, Ran can control branching through a canonical SAF, TPX2, which is non-essential in Drosophila melanogaster embryos and HeLa cells. Thus, how Ran regulates branching MT nucleation when TPX2 is not required remains unknown. Here, we use in vitro pulldowns and TIRF microscopy to show that augmin is a Ran-regulated SAF. We demonstrate that augmin directly interacts with both importin-α and importin-β through two nuclear localization sequences on the Haus8 subunit, which overlap with the MT binding site. Moreover, we show Ran controls localization of augmin to MTs in both Xenopus egg extract and in vitro. Our results demonstrate that RanGTP directly regulates augmin, which establishes a new way by which Ran controls branching MT nucleation and spindle assembly both in the absence and presence of TPX2.
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Affiliation(s)
- Jodi Kraus
- Department of Molecular Biology; Princeton University; Princeton, NJ, 08544; USA
| | - Sophie M Travis
- Department of Molecular Biology; Princeton University; Princeton, NJ, 08544; USA
| | - Matthew R King
- Department of Molecular Biology; Princeton University; Princeton, NJ, 08544; USA
| | - Sabine Petry
- Department of Molecular Biology; Princeton University; Princeton, NJ, 08544; USA.
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El-Tanani M, Nsairat H, Mishra V, Mishra Y, Aljabali AAA, Serrano-Aroca Á, Tambuwala MM. Ran GTPase and Its Importance in Cellular Signaling and Malignant Phenotype. Int J Mol Sci 2023; 24:ijms24043065. [PMID: 36834476 PMCID: PMC9968026 DOI: 10.3390/ijms24043065] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 01/10/2023] [Accepted: 01/11/2023] [Indexed: 02/08/2023] Open
Abstract
Ran is a member of the Ras superfamily of proteins, which primarily regulates nucleocytoplasmic trafficking and mediates mitosis by regulating spindle formation and nuclear envelope (NE) reassembly. Therefore, Ran is an integral cell fate determinant. It has been demonstrated that aberrant Ran expression in cancer is a result of upstream dysregulation of the expression of various factors, such as osteopontin (OPN), and aberrant activation of various signaling pathways, including the extracellular-regulated kinase/mitogen-activated protein kinase (ERK/MEK) and phosphatidylinositol 3-kinase/Protein kinase B (PI3K/Akt) pathways. In vitro, Ran overexpression has severe effects on the cell phenotype, altering proliferation, adhesion, colony density, and invasion. Therefore, Ran overexpression has been identified in numerous types of cancer and has been shown to correlate with tumor grade and the degree of metastasis present in various cancers. The increased malignancy and invasiveness have been attributed to multiple mechanisms. Increased dependence on Ran for spindle formation and mitosis is a consequence of the upregulation of these pathways and the ensuing overexpression of Ran, which increases cellular dependence on Ran for survival. This increases the sensitivity of cells to changes in Ran concentration, with ablation being associated with aneuploidy, cell cycle arrest, and ultimately, cell death. It has also been demonstrated that Ran dysregulation influences nucleocytoplasmic transport, leading to transcription factor misallocation. Consequently, patients with tumors that overexpress Ran have been shown to have a higher malignancy rate and a shorter survival time compared to their counterparts.
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Affiliation(s)
- Mohamed El-Tanani
- Pharmacological and Diagnostic Research Centre, Faculty of Pharmacy, Al-Ahliyya Amman University, Amman 19328, Jordan
- Correspondence:
| | - Hamdi Nsairat
- Pharmacological and Diagnostic Research Centre, Faculty of Pharmacy, Al-Ahliyya Amman University, Amman 19328, Jordan
| | - Vijay Mishra
- School of Pharmaceutical Sciences, Lovely Professional University, Phagwara 144411, India
| | - Yachana Mishra
- Department of Zoology, School of Bioengineering and Biosciences, Lovely Professional University, Phagwara 144411, India
| | - Alaa A. A. Aljabali
- Department of Pharmaceutics & Pharmaceutical Technology, Yarmouk University, Irbid 21163, Jordan
| | - Ángel Serrano-Aroca
- Biomaterials and Bioengineering Laboratory, Centro de Investigación Traslacional San Alberto Magno, Universidad Católica de Valencia San Vicente Mártir, c/Guillem de Castro 94, 46001 Valencia, Spain
| | - Murtaza M. Tambuwala
- Lincoln Medical School, University of Lincoln, Brayford Pool, Lincoln LN6 7TS, UK
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5
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Yeh SC, Diosa-Toro M, Tan WL, Rachenne F, Hain A, Yeo CPX, Bribes I, Xiang BWW, Sathiamoorthy Kannan G, Manuel MC, Missé D, Mok YK, Pompon J. Characterization of dengue virus 3'UTR RNA binding proteins in mosquitoes reveals that AeStaufen reduces subgenomic flaviviral RNA in saliva. PLoS Pathog 2022; 18:e1010427. [PMID: 36121894 PMCID: PMC9531803 DOI: 10.1371/journal.ppat.1010427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 10/04/2022] [Accepted: 09/09/2022] [Indexed: 11/27/2022] Open
Abstract
Dengue viruses (DENV) are expanding global pathogens that are transmitted through the bite of mosquitoes, mostly Aedes aegypti. As RNA viruses, DENV rely on RNA-binding proteins (RBPs) to complete their life cycle. Alternatively, RBPs can act as restriction factors that prevent DENV multiplication. While the importance of RBPs is well-supported in humans, there is a dearth of information about their influence on DENV transmission by mosquitoes. Such knowledge could be harnessed to design novel, effective interventions against DENV. Here, we successfully adapted RNA-affinity chromatography coupled with mass spectrometry-a technique initially developed in mammalian cells-to identify RBPs in Ae. aegypti cells. We identified fourteen RBPs interacting with DENV serotype 2 3'UTR, which is involved in the viral multiplication and produces subgenomic flaviviral RNA (sfRNA). We validated the RNA affinity results for two RBPs by confirming that AePur binds the 3'UTR, whereas AeStaufen interacts with both 3'UTR and sfRNA. Using in vivo functional evaluation, we determined that RBPs like AeRan, AeExoRNase, and AeRNase have pro-viral functions, whereas AeGTPase, AeAtu, and AePur have anti-viral functions in mosquitoes. Furthermore, we showed that human and mosquito Pur homologs have a shared affinity to DENV2 RNA, although the anti-viral effect is specific to the mosquito protein. Importantly, we revealed that AeStaufen mediates a reduction of gRNA and sfRNA copies in several mosquito tissues, including the salivary glands and that AeStaufen-mediated sfRNA reduction diminishes the concentration of transmission-enhancing sfRNA in saliva, thereby revealing AeStaufen's role in DENV transmission. By characterizing the first RBPs that associate with DENV2 3'UTR in mosquitoes, our study unravels new pro- and anti-viral targets for the design of novel therapeutic interventions as well as provides foundation for studying the role of RBPs in virus-vector interactions.
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Affiliation(s)
- Shih-Chia Yeh
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Republic of Singapore
| | - Mayra Diosa-Toro
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Republic of Singapore
| | - Wei-Lian Tan
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Republic of Singapore
| | | | - Arthur Hain
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Republic of Singapore
| | - Celestia Pei Xuan Yeo
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Republic of Singapore
| | - Inès Bribes
- MIVEGEC, Univ. Montpellier, IRD, CNRS, Montpellier, France
| | - Benjamin Wong Wei Xiang
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Republic of Singapore
| | | | - Menchie Casayuran Manuel
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Republic of Singapore
| | - Dorothée Missé
- MIVEGEC, Univ. Montpellier, IRD, CNRS, Montpellier, France
| | - Yu Keung Mok
- Department of Biological Sciences, National University of Singapore, Singapore, Republic of Singapore
| | - Julien Pompon
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Republic of Singapore
- MIVEGEC, Univ. Montpellier, IRD, CNRS, Montpellier, France
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6
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Qin Z, Wu YN, Sun TT, Ma T, Xu M, Pang C, Li SW, Li S. Arabidopsis RAN GTPases are critical for mitosis during male and female gametogenesis. FEBS Lett 2022; 596:1892-1903. [PMID: 35680649 DOI: 10.1002/1873-3468.14422] [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: 02/17/2022] [Revised: 05/30/2022] [Accepted: 05/31/2022] [Indexed: 11/09/2022]
Abstract
The development of male and female gametophytes is a prerequisite for successful propagation of angiosperms. The small GTPases RAN play fundamental roles in numerous cellular processes. Although RAN GTPases have been characterized in plants, their roles in cellular processes are far from understood. We report here that RAN GTPases in Arabidopsis are critical for gametophytic development. RAN1 loss-of-function showed no defects in gametophytic development likely due to redundancy. However, the expression of a dominant negative or constitutively active RAN1 resulted in gametophytic lethality. Genetic interference of RAN GTPases caused the arrest of pollen mitosis I and of mitosis of functional megaspores, implying a key role of properly regulated RAN activity in mitosis during gametophytic development.
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Affiliation(s)
- Zheng Qin
- Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tian'jin, China
| | - Ya-Nan Wu
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, China
| | - Tian-Tian Sun
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, China
| | - Ting Ma
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, China
| | - Meng Xu
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, China
| | - Chen Pang
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, China
| | - Shan-Wei Li
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, China
| | - Sha Li
- Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tian'jin, China.,State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, China
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7
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Yang F, Zhang N, Chen Y, Yin J, Xu M, Cheng X, Ma R, Meng J, Du Y. Role of Non-Coding RNA in Neurological Complications Associated With Enterovirus 71. Front Cell Infect Microbiol 2022; 12:873304. [PMID: 35548469 PMCID: PMC9081983 DOI: 10.3389/fcimb.2022.873304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Accepted: 03/30/2022] [Indexed: 11/13/2022] Open
Abstract
Enterovirus 71 (EV71) is the main pathogenic virus that causes hand, foot, and mouth disease (HFMD). Studies have reported that EV71-induced infections including aseptic meningitis, acute flaccid paralysis, and even neurogenic pulmonary edema, can progress to severe neurological complications in infants, young children, and the immunosuppressed population. However, the mechanisms through which EV71 causes neurological diseases have not been fully explored. Non-coding RNAs (ncRNAs), are RNAs that do not code for proteins, play a key role in biological processes and disease development associated with EV71. In this review, we summarized recent advances concerning the impacts of ncRNAs on neurological diseases caused by interaction between EV71 and host, revealing the potential role of ncRNAs in pathogenesis, diagnosis and treatment of EV71-induced neurological complications.
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Affiliation(s)
- Feixiang Yang
- School of Basic Medical Sciences, Anhui Medical University, Hefei, China
- Department of Urology, The First Affiliated Hospital of Anhui Medical University, Hefei, China
- Institute of Urology, Anhui Medical University, Hefei, China
- Anhui Province Key Laboratory of Genitourinary Diseases, Anhui Medical University, Hefei, China
| | - Ning Zhang
- School of Basic Medical Sciences, Anhui Medical University, Hefei, China
- First School of Clinical Medicine, Anhui Medical University, Hefei, China
| | - Yuxin Chen
- School of Basic Medical Sciences, Anhui Medical University, Hefei, China
- School of Public Health, Anhui Medical University, Hefei, China
| | - Jiancai Yin
- First School of Clinical Medicine, Anhui Medical University, Hefei, China
| | - Muchen Xu
- School of Basic Medical Sciences, Anhui Medical University, Hefei, China
- School of Public Health, Anhui Medical University, Hefei, China
| | - Xiang Cheng
- First School of Clinical Medicine, Anhui Medical University, Hefei, China
| | - Ruyi Ma
- School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Jialin Meng
- Department of Urology, The First Affiliated Hospital of Anhui Medical University, Hefei, China
- Institute of Urology, Anhui Medical University, Hefei, China
- Anhui Province Key Laboratory of Genitourinary Diseases, Anhui Medical University, Hefei, China
- *Correspondence: Yinan Du, ; Jialin Meng,
| | - Yinan Du
- School of Basic Medical Sciences, Anhui Medical University, Hefei, China
- *Correspondence: Yinan Du, ; Jialin Meng,
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8
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Miceli M, Exertier C, Cavaglià M, Gugole E, Boccardo M, Casaluci RR, Ceccarelli N, De Maio A, Vallone B, Deriu MA. ALS2-Related Motor Neuron Diseases: From Symptoms to Molecules. BIOLOGY 2022; 11:77. [PMID: 35053075 PMCID: PMC8773251 DOI: 10.3390/biology11010077] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 12/22/2021] [Accepted: 12/29/2021] [Indexed: 11/27/2022]
Abstract
Infantile-onset Ascending Hereditary Spastic Paralysis, Juvenile Primary Lateral Sclerosis and Juvenile Amyotrophic Lateral Sclerosis are all motor neuron diseases related to mutations on the ALS2 gene, encoding for a 1657 amino acids protein named Alsin. This ~185 kDa multi-domain protein is ubiquitously expressed in various human tissues, mostly in the brain and the spinal cord. Several investigations have indicated how mutations within Alsin's structured domains may be responsible for the alteration of Alsin's native oligomerization state or Alsin's propensity to interact with protein partners. In this review paper, we propose a description of differences and similarities characterizing the above-mentioned ALS2-related rare neurodegenerative disorders, pointing attention to the effects of ALS2 mutation from molecule to organ and at the system level. Known cases were collected through a literature review and rationalized to deeply elucidate the neurodegenerative clinical outcomes as consequences of ALS2 mutations.
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Affiliation(s)
- Marcello Miceli
- PolitoBIOMedLab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, 10129 Torino, Italy; (M.M.); (M.C.); (M.B.); (R.R.C.); (N.C.); (A.D.M.)
| | - Cécile Exertier
- Dipartimento di Scienze Biochimiche “A. Rossi Fanelli”, Sapienza Università di Roma, 00185 Rome, Italy; (C.E.); (E.G.); (B.V.)
| | - Marco Cavaglià
- PolitoBIOMedLab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, 10129 Torino, Italy; (M.M.); (M.C.); (M.B.); (R.R.C.); (N.C.); (A.D.M.)
| | - Elena Gugole
- Dipartimento di Scienze Biochimiche “A. Rossi Fanelli”, Sapienza Università di Roma, 00185 Rome, Italy; (C.E.); (E.G.); (B.V.)
| | - Marta Boccardo
- PolitoBIOMedLab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, 10129 Torino, Italy; (M.M.); (M.C.); (M.B.); (R.R.C.); (N.C.); (A.D.M.)
| | - Rossana Rita Casaluci
- PolitoBIOMedLab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, 10129 Torino, Italy; (M.M.); (M.C.); (M.B.); (R.R.C.); (N.C.); (A.D.M.)
| | - Noemi Ceccarelli
- PolitoBIOMedLab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, 10129 Torino, Italy; (M.M.); (M.C.); (M.B.); (R.R.C.); (N.C.); (A.D.M.)
| | - Alessandra De Maio
- PolitoBIOMedLab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, 10129 Torino, Italy; (M.M.); (M.C.); (M.B.); (R.R.C.); (N.C.); (A.D.M.)
| | - Beatrice Vallone
- Dipartimento di Scienze Biochimiche “A. Rossi Fanelli”, Sapienza Università di Roma, 00185 Rome, Italy; (C.E.); (E.G.); (B.V.)
| | - Marco A. Deriu
- PolitoBIOMedLab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, 10129 Torino, Italy; (M.M.); (M.C.); (M.B.); (R.R.C.); (N.C.); (A.D.M.)
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9
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Baker MJ, Rubio I. Active GTPase Pulldown Protocol. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2021; 2262:117-135. [PMID: 33977474 DOI: 10.1007/978-1-0716-1190-6_7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Ras and its related small GTPases are important signalling nodes that regulate a wide variety of cellular functions. The active form of these proteins exists in a transient GTP bound state that mediates downstream signalling events. The dysregulation of these GTPases has been associated with the progression of multiple diseases, most prominently cancer and developmental syndromes known as Rasopathies. Determining the activation state of Ras and its relatives has hence been of paramount importance for the investigation of the biochemical functions of small GTPases in the cellular signal transduction network. This chapter describes the most broadly employed approach for the rapid, label-free qualitative and semi-quantitative determination of the Ras GTPase activation state, which can readily be adapted to the analysis of other related GTPases. The method relies on the affinity-based isolation of the active GTP-bound fraction of Ras in cellular extracts, followed by its visualization via western blotting. Specifically, we describe the production of the recombinant affinity probes or baits that bind to the respective active GTPases and the pulldown method for isolating the active GTPase fraction from adherent or non-adherent cells. This method allows for the reproducible measurement of active Ras or Ras family GTPases in a wide variety of cellular contexts.
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Affiliation(s)
- Martin J Baker
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Ignacio Rubio
- Institute of Molecular Cell Biology, Center for Molecular Biomedicine, University Hospital Jena, Jena, Germany. .,Clinic for Anaesthesiology and Intensive Care, University Hospital Jena, Jena, Germany.
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10
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Shatskikh AS, Kotov AA, Adashev VE, Bazylev SS, Olenina LV. Functional Significance of Satellite DNAs: Insights From Drosophila. Front Cell Dev Biol 2020; 8:312. [PMID: 32432114 PMCID: PMC7214746 DOI: 10.3389/fcell.2020.00312] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Accepted: 04/08/2020] [Indexed: 12/12/2022] Open
Abstract
Since their discovery more than 60 years ago, satellite repeats are still one of the most enigmatic parts of eukaryotic genomes. Being non-coding DNA, satellites were earlier considered to be non-functional “junk,” but recently this concept has been extensively revised. Satellite DNA contributes to the essential processes of formation of crucial chromosome structures, heterochromatin establishment, dosage compensation, reproductive isolation, genome stability and development. Genomic abundance of satellites is under stabilizing selection owing of their role in the maintenance of vital regions of the genome – centromeres, pericentromeric regions, and telomeres. Many satellites are transcribed with the generation of long or small non-coding RNAs. Misregulation of their expression is found to lead to various defects in the maintenance of genomic architecture, chromosome segregation and gametogenesis. This review summarizes our current knowledge concerning satellite functions, the mechanisms of regulation and evolution of satellites, focusing on recent findings in Drosophila. We discuss here experimental and bioinformatics data obtained in Drosophila in recent years, suggesting relevance of our analysis to a wide range of eukaryotic organisms.
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Affiliation(s)
- Aleksei S Shatskikh
- Laboratory of Analysis of Clinical and Model Tumor Pathologies on the Organismal Level, Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russia
| | - Alexei A Kotov
- Laboratory of Biochemical Genetics of Animals, Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russia
| | - Vladimir E Adashev
- Laboratory of Biochemical Genetics of Animals, Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russia
| | - Sergei S Bazylev
- Laboratory of Biochemical Genetics of Animals, Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russia
| | - Ludmila V Olenina
- Laboratory of Biochemical Genetics of Animals, Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russia
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11
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Serway CN, Dunkelberger BS, Del Padre D, Nolan NWC, Georges S, Freer S, Andres AJ, de Belle JS. Importin-α2 mediates brain development, learning and memory consolidation in Drosophila. J Neurogenet 2020; 34:69-82. [PMID: 31965871 DOI: 10.1080/01677063.2019.1709184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Neuronal development and memory consolidation are conserved processes that rely on nuclear-cytoplasmic transport of signaling molecules to regulate gene activity and initiate cascades of downstream cellular events. Surprisingly, few reports address and validate this widely accepted perspective. Here we show that Importin-α2 (Imp-α2), a soluble nuclear transporter that shuttles cargoes between the cytoplasm and nucleus, is vital for brain development, learning and persistent memory in Drosophila melanogaster. Mutations in importin-α2 (imp-α2, known as Pendulin or Pen and homologous with human KPNA2) are alleles of mushroom body miniature B (mbmB), a gene known to regulate aspects of brain development and influence adult behavior in flies. Mushroom bodies (MBs), paired associative centers in the brain, are smaller than normal due to defective proliferation of specific intrinsic Kenyon cell (KC) neurons in mbmB mutants. Extant KCs projecting to the MB β-lobe terminate abnormally on the contralateral side of the brain. mbmB adults have impaired olfactory learning but normal memory decay in most respects, except that protein synthesis-dependent long-term memory (LTM) is abolished. This observation supports an alternative mechanism of persistent memory in which mutually exclusive protein-synthesis-dependent and -independent forms rely on opposing cellular mechanisms or circuits. We propose a testable model of Imp-α2 and nuclear transport roles in brain development and conditioned behavior. Based on our molecular characterization, we suggest that mbmB is hereafter referred to as imp-α2mbmB.
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Affiliation(s)
- Christine N Serway
- School of Life Sciences, University of Nevada, Las Vegas, NV, USA.,Comprehensive Cancer Center, University of New Mexico, Albuquerque, NM, USA
| | - Brian S Dunkelberger
- School of Life Sciences, University of Nevada, Las Vegas, NV, USA.,Las Vegas High School, Las Vegas, NV, USA
| | - Denise Del Padre
- School of Life Sciences, University of Nevada, Las Vegas, NV, USA
| | - Nicole W C Nolan
- School of Life Sciences, University of Nevada, Las Vegas, NV, USA.,Methodist Estabrook Cancer Center, Omaha, NE, USA
| | - Stephanie Georges
- School of Life Sciences, University of Nevada, Las Vegas, NV, USA.,Department of Human Genetics, University of Utah, Salt Lake City, UT, USA
| | - Stephanie Freer
- School of Life Sciences, University of Nevada, Las Vegas, NV, USA.,Research Square Inc, Nashville, TN, USA
| | - Andrew J Andres
- School of Life Sciences, University of Nevada, Las Vegas, NV, USA
| | - J Steven de Belle
- School of Life Sciences, University of Nevada, Las Vegas, NV, USA.,Department of Psychological Sciences, University of San Diego, San Diego, CA, USA
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12
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Yao L, Zhou Y, Sui Z, Zhang Y, Liu Y, Xie H, Gao H, Fan H, Zhang Y, Liu M, Li S, Tang H. HBV-encoded miR-2 functions as an oncogene by downregulating TRIM35 but upregulating RAN in liver cancer cells. EBioMedicine 2019; 48:117-129. [PMID: 31530503 PMCID: PMC6838411 DOI: 10.1016/j.ebiom.2019.09.012] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 08/24/2019] [Accepted: 09/06/2019] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Hepatitis B virus (HBV) infection has been well established as a high-risk factor for the carcinogenesis of hepatocellular carcinoma (HCC). Cellular microRNA (miRNA) is involved in tumorigenesis by accelerating the malignant phenotype in HCC. However, whether HBV can encode miRNAs that contribute to HCC is not entirely clear. METHODS In this study, an miRNA encoded by HBV (HBV-miR-2) was identified by Solexa sequencing in HBV-positive HCC specimens and further verified in serum samples from HCC patients with HBV infection and in HBV-positive HCC cell lines. To evaluate the roles of HBV-miR-2 in liver cancer cells, we determined cell viability and migration/invasion ability by gain-of-function experiment in HBV(-) liver cancer cells (HepG2 and Huh7) and loss-of-function experiments in Huh7 cells stably expressing HBV-miR-2 (Huh7/HBV-miR-2 cells) and HepG2.2.15 cells. Furthermore, to elucidate the mechanism by which HBV-miR-2 work on cell malignancy, we identified and studied the effect of two target genes (TRIM35 and RAN) of HBV-miR-2 in liver cancer cells. FINDINGS We revealed that HBV-miR-2 promoted HCC cell growth ability by suppressing apoptosis and promoting migration and invasion by enhancing the epithelial-mesenchymal transition (EMT), functioning as an oncogene in the development of HBV-related HCC. Furthermore, we demonstrated that HBV-miR-2 suppresses the expression of TRIM35 but enhances RAN expression by targeting their 3'-untranslated regions (3'UTR) and that the ectopic expression of TRIM35 or knockdown of RAN counteracted the malignant phenotypes induced by HBV-miR-2. INTERPRETATION Our findings indicate that an HBV-encoded miRNA, HBV-miR-2, promotes oncogenic activity by downregulating TRIM35 expression and upregulating RAN expression in liver cancer cells, likely providing insight into tumorigenesis in HBV-related liver cancer. FUND: This work was supported in part by the National Natural Science Foundation of China (No: 81830094; 91629302; 31270818) and the Natural Science Foundation of Tianjin (No: 12JCZDJC25100).
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Affiliation(s)
- Lili Yao
- Tianjin Life Science Research Center, Tianjin Laboratory of Inflammation Biology, Collaborative Innovation Center of Tianjin for Medical Epigenetics, Department of Pathogen Biology, Basic Medical School, Tianjin Medical University, Tianjin 300070, China
| | - Yadi Zhou
- Tianjin Life Science Research Center, Tianjin Laboratory of Inflammation Biology, Collaborative Innovation Center of Tianjin for Medical Epigenetics, Department of Pathogen Biology, Basic Medical School, Tianjin Medical University, Tianjin 300070, China
| | - Zhenhua Sui
- Tianjin Life Science Research Center, Tianjin Laboratory of Inflammation Biology, Collaborative Innovation Center of Tianjin for Medical Epigenetics, Department of Pathogen Biology, Basic Medical School, Tianjin Medical University, Tianjin 300070, China
| | - Yanling Zhang
- Tianjin Life Science Research Center, Tianjin Laboratory of Inflammation Biology, Collaborative Innovation Center of Tianjin for Medical Epigenetics, Department of Pathogen Biology, Basic Medical School, Tianjin Medical University, Tianjin 300070, China
| | - Yankun Liu
- The Cancer Institute, Tangshan People's Hospital, Tangshan 063001, China
| | - Hong Xie
- Tianjin Life Science Research Center, Tianjin Laboratory of Inflammation Biology, Collaborative Innovation Center of Tianjin for Medical Epigenetics, Department of Pathogen Biology, Basic Medical School, Tianjin Medical University, Tianjin 300070, China.
| | - Huijie Gao
- Tianjin Life Science Research Center, Tianjin Laboratory of Inflammation Biology, Collaborative Innovation Center of Tianjin for Medical Epigenetics, Department of Pathogen Biology, Basic Medical School, Tianjin Medical University, Tianjin 300070, China
| | - Hongxia Fan
- Tianjin Life Science Research Center, Tianjin Laboratory of Inflammation Biology, Collaborative Innovation Center of Tianjin for Medical Epigenetics, Department of Pathogen Biology, Basic Medical School, Tianjin Medical University, Tianjin 300070, China
| | - Yi Zhang
- Tianjin Life Science Research Center, Tianjin Laboratory of Inflammation Biology, Collaborative Innovation Center of Tianjin for Medical Epigenetics, Department of Pathogen Biology, Basic Medical School, Tianjin Medical University, Tianjin 300070, China
| | - Min Liu
- Tianjin Life Science Research Center, Tianjin Laboratory of Inflammation Biology, Collaborative Innovation Center of Tianjin for Medical Epigenetics, Department of Pathogen Biology, Basic Medical School, Tianjin Medical University, Tianjin 300070, China
| | - Shengping Li
- State Key Laboratory of Oncology in Southern China, Department of Hepatobiliary Oncology, Cancer Center, Sun Yat-sen University, Guangzhou 510060, China.
| | - Hua Tang
- Tianjin Life Science Research Center, Tianjin Laboratory of Inflammation Biology, Collaborative Innovation Center of Tianjin for Medical Epigenetics, Department of Pathogen Biology, Basic Medical School, Tianjin Medical University, Tianjin 300070, China.
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13
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Greenwald EC, Mehta S, Zhang J. Genetically Encoded Fluorescent Biosensors Illuminate the Spatiotemporal Regulation of Signaling Networks. Chem Rev 2018; 118:11707-11794. [PMID: 30550275 PMCID: PMC7462118 DOI: 10.1021/acs.chemrev.8b00333] [Citation(s) in RCA: 316] [Impact Index Per Article: 52.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Cellular signaling networks are the foundation which determines the fate and function of cells as they respond to various cues and stimuli. The discovery of fluorescent proteins over 25 years ago enabled the development of a diverse array of genetically encodable fluorescent biosensors that are capable of measuring the spatiotemporal dynamics of signal transduction pathways in live cells. In an effort to encapsulate the breadth over which fluorescent biosensors have expanded, we endeavored to assemble a comprehensive list of published engineered biosensors, and we discuss many of the molecular designs utilized in their development. Then, we review how the high temporal and spatial resolution afforded by fluorescent biosensors has aided our understanding of the spatiotemporal regulation of signaling networks at the cellular and subcellular level. Finally, we highlight some emerging areas of research in both biosensor design and applications that are on the forefront of biosensor development.
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Affiliation(s)
- Eric C Greenwald
- University of California , San Diego, 9500 Gilman Drive, BRFII , La Jolla , CA 92093-0702 , United States
| | - Sohum Mehta
- University of California , San Diego, 9500 Gilman Drive, BRFII , La Jolla , CA 92093-0702 , United States
| | - Jin Zhang
- University of California , San Diego, 9500 Gilman Drive, BRFII , La Jolla , CA 92093-0702 , United States
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14
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Inoue D, Wittbrodt J, Gruss OJ. Loss and Rebirth of the Animal Microtubule Organizing Center: How Maternal Expression of Centrosomal Proteins Cooperates with the Sperm Centriole in Zygotic Centrosome Reformation. Bioessays 2018. [PMID: 29522658 DOI: 10.1002/bies.201700135] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Centrosomes are the main microtubule organizing centers in animal cells. In particular during embryogenesis, they ensure faithful spindle formation and proper cell divisions. As metazoan centrosomes are eliminated during oogenesis, they have to be reassembled upon fertilization. Most metazoans use the sperm centrioles as templates for new centrosome biogenesis while the egg's cytoplasm re-prepares all components for on-going centrosome duplication in rapidly dividing embryonic cells. We discuss our knowledge and the experimental challenges to analyze zygotic centrosome reformation, which requires genetic experiments to enable scrutinizing respective male and female contributions. Male and female knockout animals and mRNA injection to mimic maternal expression of centrosomal proteins could point a way to the systematic molecular dissection of the process. The most recent data suggest that timely expression of centrosome components in oocytes is the key to zygotic centrosome reformation that uses male sperm as coordinators for de novo centrosome production.
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Affiliation(s)
- Daigo Inoue
- Dr. D. Inoue, Prof. Dr. J. Wittbrodt, Centre of Organismal Studies, University of Heidelberg, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
| | - Joachim Wittbrodt
- Dr. D. Inoue, Prof. Dr. J. Wittbrodt, Centre of Organismal Studies, University of Heidelberg, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
| | - Oliver J Gruss
- Prof. Dr. O. J. Gruss, Institute of Genetics, University of Bonn, Karlrobert-Kreiten-Str.13, 53115 Bonn, Germany
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15
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RanGTPase regulates the interaction between the inner nuclear membrane proteins, Samp1 and Emerin. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:1326-1334. [PMID: 29510091 DOI: 10.1016/j.bbamem.2018.03.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Revised: 02/07/2018] [Accepted: 03/01/2018] [Indexed: 02/02/2023]
Abstract
Samp1, spindle associated membrane protein 1, is a type II integral membrane protein localized in the inner nuclear membrane. Recent studies have shown that the inner nuclear membrane protein, Emerin and the small monomeric GTPase, Ran are direct binding partners of Samp1. Here we addressed the question whether Ran could regulate the interaction between Samp1 and Emerin in the inner nuclear membrane. To investigate the interaction between Samp1 and Emerin in live cells, we performed FRAP experiments in cells overexpressing YFP-Emerin. We compared the mobility of YFP-Emerin in Samp1 knock out cells and cells overexpressing Samp1. The results showed that the mobility of YFP-Emerin was higher in Samp1 knock out cells and lower in cells overexpressing Samp1, suggesting that Samp1 significantly attenuates the mobility of Emerin in the nuclear envelope. FRAP experiments using tsBN2 cells showed that the mobility of Emerin depends on RanGTP. Consistently, in vitro binding experiments showed that the affinity between Samp1 and Emerin is decreased in the presence of Ran, suggesting that Ran attenuates the interaction between Samp1 and Emerin. This is the first demonstration that Ran can regulate the interaction between two proteins in the nuclear envelope.
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16
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Cha K, Sen P, Raghunayakula S, Zhang XD. The Cellular Distribution of RanGAP1 Is Regulated by CRM1-Mediated Nuclear Export in Mammalian Cells. PLoS One 2015; 10:e0141309. [PMID: 26506250 PMCID: PMC4624696 DOI: 10.1371/journal.pone.0141309] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2015] [Accepted: 10/07/2015] [Indexed: 11/19/2022] Open
Abstract
The Ran GTPase activating protein RanGAP1 plays an essential role in nuclear transport by stimulating RanGTP hydrolysis in the cytoplasmic compartment. In mammalian cells, unmodified RanGAP1 is predominantly cytoplasmic, whereas modification by small ubiquitin-related modifier protein (SUMO) targets RanGAP1 to the cytoplasmic filaments of nuclear pore complex (NPC). Although RanGAP1 contains nine putative nuclear export signals and a nuclear localization signal, little is known if RanGAP1 shuttles between the nuclear and cytoplasmic compartments and how its primary localization in the cytoplasm and at the NPC is regulated. Here we show that inhibition of CRM1-mediated nuclear export using RNAi-knockdown of CRM1 and inactivation of CRM1 by leptomycin B (LMB) results in nuclear accumulation of RanGAP1. LMB treatment induced a more robust redistribution of RanGAP1 from the cytoplasm to the nucleoplasm compared to CRM1 RNAi and also uniquely triggered a decrease or loss of RanGAP1 localization at the NPC, suggesting that LMB treatment is more effective in inhibiting CRM1-mediated nuclear export of RanGAP1. Our time-course analysis of LMB treatment reveals that the NPC-associated RanGAP1 is much more slowly redistributed to the nucleoplasm than the cytoplasmic RanGAP1. Furthermore, LMB-induced nuclear accumulation of RanGAP1 is positively correlated with an increase in levels of SUMO-modified RanGAP1, suggesting that SUMOylation of RanGAP1 may mainly take place in the nucleoplasm. Lastly, we demonstrate that the nuclear localization signal at the C-terminus of RanGAP1 is required for its nuclear accumulation in cells treated with LMB. Taken together, our results elucidate that RanGAP1 is actively transported between the nuclear and cytoplasmic compartments, and that the cytoplasmic and NPC localization of RanGAP1 is dependent on CRM1-mediated nuclear export.
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Affiliation(s)
- Keith Cha
- Department of Biological Sciences, Wayne State University, Detroit, Michigan, United States of America
| | - Progga Sen
- Department of Biological Sciences, Wayne State University, Detroit, Michigan, United States of America
| | - Sarita Raghunayakula
- Department of Biological Sciences, Wayne State University, Detroit, Michigan, United States of America
| | - Xiang-Dong Zhang
- Department of Biological Sciences, Wayne State University, Detroit, Michigan, United States of America
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17
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Spatiotemporal Regulation of Nuclear Transport Machinery and Microtubule Organization. Cells 2015; 4:406-26. [PMID: 26308057 PMCID: PMC4588043 DOI: 10.3390/cells4030406] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Revised: 07/30/2015] [Accepted: 08/19/2015] [Indexed: 12/23/2022] Open
Abstract
Spindle microtubules capture and segregate chromosomes and, therefore, their assembly is an essential event in mitosis. To carry out their mission, many key players for microtubule formation need to be strictly orchestrated. Particularly, proteins that assemble the spindle need to be translocated at appropriate sites during mitosis. A small GTPase (hydrolase enzyme of guanosine triphosphate), Ran, controls this translocation. Ran plays many roles in many cellular events: nucleocytoplasmic shuttling through the nuclear envelope, assembly of the mitotic spindle, and reorganization of the nuclear envelope at the mitotic exit. Although these events are seemingly distinct, recent studies demonstrate that the mechanisms underlying these phenomena are substantially the same as explained by molecular interplay of the master regulator Ran, the transport factor importin, and its cargo proteins. Our review focuses on how the transport machinery regulates mitotic progression of cells. We summarize translocation mechanisms governed by Ran and its regulatory proteins, and particularly focus on Ran-GTP targets in fission yeast that promote spindle formation. We also discuss the coordination of the spatial and temporal regulation of proteins from the viewpoint of transport machinery. We propose that the transport machinery is an essential key that couples the spatial and temporal events in cells.
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18
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Lucena R, Dephoure N, Gygi SP, Kellogg DR, Tallada VA, Daga RR, Jimenez J. Nucleocytoplasmic transport in the midzone membrane domain controls yeast mitotic spindle disassembly. ACTA ACUST UNITED AC 2015; 209:387-402. [PMID: 25963819 PMCID: PMC4427787 DOI: 10.1083/jcb.201412144] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
During anaphase B, Imp1-mediated transport of the AAA-ATPase Cdc48 protein at the membrane domain surrounding the mitotic spindle midzone promotes spindle midzone dissolution in fission yeast. During each cell cycle, the mitotic spindle is efficiently assembled to achieve chromosome segregation and then rapidly disassembled as cells enter cytokinesis. Although much has been learned about assembly, how spindles disassemble at the end of mitosis remains unclear. Here we demonstrate that nucleocytoplasmic transport at the membrane domain surrounding the mitotic spindle midzone, here named the midzone membrane domain (MMD), is essential for spindle disassembly in Schizosaccharomyces pombe cells. We show that, during anaphase B, Imp1-mediated transport of the AAA-ATPase Cdc48 protein at the MMD allows this disassembly factor to localize at the spindle midzone, thereby promoting spindle midzone dissolution. Our findings illustrate how a separate membrane compartment supports spindle disassembly in the closed mitosis of fission yeast.
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Affiliation(s)
- Rafael Lucena
- Centro Andaluz de Biología del Desarrollo. Universidad Pablo de Olavide/Consejo Superior de Investigaciones Cientificas, 41013 Sevilla, Spain Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA 95064
| | - Noah Dephoure
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115
| | - Steve P Gygi
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115
| | - Douglas R Kellogg
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA 95064
| | - Victor A Tallada
- Centro Andaluz de Biología del Desarrollo. Universidad Pablo de Olavide/Consejo Superior de Investigaciones Cientificas, 41013 Sevilla, Spain
| | - Rafael R Daga
- Centro Andaluz de Biología del Desarrollo. Universidad Pablo de Olavide/Consejo Superior de Investigaciones Cientificas, 41013 Sevilla, Spain
| | - Juan Jimenez
- Centro Andaluz de Biología del Desarrollo. Universidad Pablo de Olavide/Consejo Superior de Investigaciones Cientificas, 41013 Sevilla, Spain
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19
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Droppelmann CA, Campos-Melo D, Volkening K, Strong MJ. The emerging role of guanine nucleotide exchange factors in ALS and other neurodegenerative diseases. Front Cell Neurosci 2014; 8:282. [PMID: 25309324 PMCID: PMC4159981 DOI: 10.3389/fncel.2014.00282] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 08/25/2014] [Indexed: 12/11/2022] Open
Abstract
Small GTPases participate in a broad range of cellular processes such as proliferation, differentiation, and migration. The exchange of GDP for GTP resulting in the activation of these GTPases is catalyzed by a group of enzymes called guanine nucleotide exchange factors (GEFs), of which two classes: Dbl-related exchange factors and the more recently described dedicator of cytokinesis proteins family exchange factors. Increasingly, deregulation of normal GEF activity or function has been associated with a broad range of disease states, including neurodegeneration and neurodevelopmental disorders. In this review, we examine this evidence with special emphasis on the novel role of Rho guanine nucleotide exchange factor (RGNEF/p190RhoGEF) in the pathogenesis of amyotrophic lateral sclerosis. RGNEF is the first neurodegeneration-linked GEF that regulates not only RhoA GTPase activation but also functions as an RNA binding protein that directly acts with low molecular weight neurofilament mRNA 3' untranslated region to regulate its stability. This dual role for RGNEF, coupled with the increasing understanding of the key role for GEFs in modulating the GTPase function in cell survival suggests a prominent role for GEFs in mediating a critical balance between cytotoxicity and neuroprotection which, when disturbed, contributes to neuronal loss.
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Affiliation(s)
- Cristian A Droppelmann
- Molecular Medicine Group, Robarts Research Institute, Western University London, ON, Canada
| | - Danae Campos-Melo
- Molecular Medicine Group, Robarts Research Institute, Western University London, ON, Canada
| | - Kathryn Volkening
- Molecular Medicine Group, Robarts Research Institute, Western University London, ON, Canada ; Department of Clinical Neurological Sciences, Schulich School of Medicine & Dentistry, Western University London, ON, Canada
| | - Michael J Strong
- Molecular Medicine Group, Robarts Research Institute, Western University London, ON, Canada ; Department of Clinical Neurological Sciences, Schulich School of Medicine & Dentistry, Western University London, ON, Canada
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20
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Marchiani S, Tamburrino L, Ricci B, Nosi D, Cambi M, Piomboni P, Belmonte G, Forti G, Muratori M, Baldi E. SUMO1 in human sperm: new targets, role in motility and morphology and relationship with DNA damage. Reproduction 2014; 148:453-67. [PMID: 25118297 DOI: 10.1530/rep-14-0173] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
In studies carried out previously, we demonstrated that small ubiquitin-like modifier 1 (SUMO1) is associated with poor sperm motility when evaluated with a protocol that reveals mostly SUMO1-ylated live sperm. Recently, with another protocol, it has been demonstrated that SUMO is expressed in most sperm and is related to poor morphology and motility, suggesting that sumoylation may have multiple roles depending on its localisation and targets. We show herein, by confocal microscopy and co-immunoprecipitation, that dynamin-related protein 1 (DRP1), Ran GTPase-activating protein 1 (RanGAP1) and Topoisomerase IIα, SUMO1 targets in somatic and/or germ cells, are SUMO1-ylated in mature human spermatozoa. DRP1 co-localises with SUMO1 in the mid-piece, whereas RanGAP1 and Topoisomerase IIα in the post-acrosomal region of the head. Both SUMO1 expression and co-localisation with the three proteins were significantly higher in morphologically abnormal sperm, suggesting that sumoylation represents a marker of defective sperm. DRP1 sumoylation at the mid-piece level was higher in the sperm of asthenospermic men. As in somatic cells, DRP1 sumoylation is associated with mitochondrial alterations, this protein may represent the link between SUMO and poor motility. As SUMO pathways are involved in responses to DNA damage, another aim of our study was to investigate the relationship between sumoylation and sperm DNA fragmentation (SDF). By flow cytometry, we demonstrated that SUMO1-ylation and SDF are correlated (r=0.4, P<0.02, n=37) and most sumoylated sperm shows DNA damage in co-localisation analysis. When SDF was induced by stressful conditions (freezing and thawing and oxidative stress), SUMO1-ylation increased. Following freezing and thawing, SUMO1-Topoisomerase IIα co-localisation and co-immunoprecipitation increased, suggesting an involvement in the formation/repair of DNA breakage.
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Affiliation(s)
- S Marchiani
- Department of BiomedicalExperimental and Clinical Sciences, Center of Excellence DeNotheDepartment of Experimental and Clinical MedicineUniversity of Florence, Viale Pieraccini 6, I-50139 Florence, ItalyDepartments of Molecular and Developmental MedicineMedicalSurgical and Neurological Sciences, University of Siena, 53100 Siena, Italy
| | - L Tamburrino
- Department of BiomedicalExperimental and Clinical Sciences, Center of Excellence DeNotheDepartment of Experimental and Clinical MedicineUniversity of Florence, Viale Pieraccini 6, I-50139 Florence, ItalyDepartments of Molecular and Developmental MedicineMedicalSurgical and Neurological Sciences, University of Siena, 53100 Siena, Italy
| | - B Ricci
- Department of BiomedicalExperimental and Clinical Sciences, Center of Excellence DeNotheDepartment of Experimental and Clinical MedicineUniversity of Florence, Viale Pieraccini 6, I-50139 Florence, ItalyDepartments of Molecular and Developmental MedicineMedicalSurgical and Neurological Sciences, University of Siena, 53100 Siena, Italy
| | - D Nosi
- Department of BiomedicalExperimental and Clinical Sciences, Center of Excellence DeNotheDepartment of Experimental and Clinical MedicineUniversity of Florence, Viale Pieraccini 6, I-50139 Florence, ItalyDepartments of Molecular and Developmental MedicineMedicalSurgical and Neurological Sciences, University of Siena, 53100 Siena, Italy
| | - M Cambi
- Department of BiomedicalExperimental and Clinical Sciences, Center of Excellence DeNotheDepartment of Experimental and Clinical MedicineUniversity of Florence, Viale Pieraccini 6, I-50139 Florence, ItalyDepartments of Molecular and Developmental MedicineMedicalSurgical and Neurological Sciences, University of Siena, 53100 Siena, Italy
| | - P Piomboni
- Department of BiomedicalExperimental and Clinical Sciences, Center of Excellence DeNotheDepartment of Experimental and Clinical MedicineUniversity of Florence, Viale Pieraccini 6, I-50139 Florence, ItalyDepartments of Molecular and Developmental MedicineMedicalSurgical and Neurological Sciences, University of Siena, 53100 Siena, Italy
| | - G Belmonte
- Department of BiomedicalExperimental and Clinical Sciences, Center of Excellence DeNotheDepartment of Experimental and Clinical MedicineUniversity of Florence, Viale Pieraccini 6, I-50139 Florence, ItalyDepartments of Molecular and Developmental MedicineMedicalSurgical and Neurological Sciences, University of Siena, 53100 Siena, Italy
| | - G Forti
- Department of BiomedicalExperimental and Clinical Sciences, Center of Excellence DeNotheDepartment of Experimental and Clinical MedicineUniversity of Florence, Viale Pieraccini 6, I-50139 Florence, ItalyDepartments of Molecular and Developmental MedicineMedicalSurgical and Neurological Sciences, University of Siena, 53100 Siena, Italy
| | - M Muratori
- Department of BiomedicalExperimental and Clinical Sciences, Center of Excellence DeNotheDepartment of Experimental and Clinical MedicineUniversity of Florence, Viale Pieraccini 6, I-50139 Florence, ItalyDepartments of Molecular and Developmental MedicineMedicalSurgical and Neurological Sciences, University of Siena, 53100 Siena, Italy
| | - E Baldi
- Department of BiomedicalExperimental and Clinical Sciences, Center of Excellence DeNotheDepartment of Experimental and Clinical MedicineUniversity of Florence, Viale Pieraccini 6, I-50139 Florence, ItalyDepartments of Molecular and Developmental MedicineMedicalSurgical and Neurological Sciences, University of Siena, 53100 Siena, Italy
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21
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Okada N, Toda T, Yamamoto M, Sato M. CDK-dependent phosphorylation of Alp7-Alp14 (TACC-TOG) promotes its nuclear accumulation and spindle microtubule assembly. Mol Biol Cell 2014; 25:1969-82. [PMID: 24790093 PMCID: PMC4072571 DOI: 10.1091/mbc.e13-11-0679] [Citation(s) in RCA: 25] [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: 11/18/2013] [Revised: 04/21/2014] [Accepted: 04/22/2014] [Indexed: 11/23/2022] Open
Abstract
As cells transition from interphase to mitosis, the microtubule cytoskeleton is reorganized to form the mitotic spindle. In the closed mitosis of fission yeast, a microtubule-associated protein complex, Alp7-Alp14 (transforming acidic coiled-coil-tumor overexpressed gene), enters the nucleus upon mitotic entry and promotes spindle formation. However, how the complex is controlled to accumulate in the nucleus only during mitosis remains elusive. Here we demonstrate that Alp7-Alp14 is excluded from the nucleus during interphase using the nuclear export signal in Alp14 but is accumulated in the nucleus during mitosis through phosphorylation of Alp7 by the cyclin-dependent kinase (CDK). Five phosphorylation sites reside around the nuclear localization signal of Alp7, and the phosphodeficient alp7-5A mutant fails to accumulate in the nucleus during mitosis and exhibits partial spindle defects. Thus our results reveal one way that CDK regulates spindle assembly at mitotic entry: CDK phosphorylates the Alp7-Alp14 complex to localize it to the nucleus.
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Affiliation(s)
- Naoyuki Okada
- Department of Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, Tokyo 113-0033, Japan
| | - Takashi Toda
- Laboratory of Cell Regulation, Cancer Research UK London Research Institute, London WC2A 3LY, United Kingdom
| | - Masayuki Yamamoto
- Department of Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, Tokyo 113-0033, JapanLaboratory of Cell Response, National Institute for Basic Biology, Okazaki 444-8585, Japan
| | - Masamitsu Sato
- Department of Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, Tokyo 113-0033, JapanDepartment of Life Science and Medical Bioscience, Graduate School of Advanced Science and Engineering, Waseda University, Center for Advanced Biomedical Sciences (TWIns), Tokyo 162-8480, JapanPrecursory Research for Embryonic Science and Technology, Japan Science and Technology Agency, Kawaguchi 332-0012, Japan
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22
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Wang PH, Huang T, Zhang X, He JG. Antiviral defense in shrimp: from innate immunity to viral infection. Antiviral Res 2014; 108:129-41. [PMID: 24886688 DOI: 10.1016/j.antiviral.2014.05.013] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Revised: 05/11/2014] [Accepted: 05/22/2014] [Indexed: 12/01/2022]
Abstract
The culture of penaeid shrimp is rapidly developing as a major business endeavor worldwide. However, viral diseases have caused huge economic loss in penaeid shrimp culture industries. Knowledge of shrimp innate immunity and antiviral responses has made important progress in recent years, allowing the design of better strategies for the prevention and control of shrimp diseases. In this study, we have updated information on shrimp antiviral immunity and interactions between shrimp hosts and viral pathogens. Current knowledge and recent progress in immune signaling pathways (e.g., Toll/IMD-NF-κB and JAK-STAT signaling pathways), RNAi, phagocytosis, and apoptosis in shrimp antiviral immunity are discussed. The mechanism of viral infection in shrimp hosts and the interactions between viruses and shrimp innate immune systems are also analyzed.
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Affiliation(s)
- Pei-Hui Wang
- MOE Key Laboratory of Aquatic Product Safety/State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, 135 Xingang Road West, Guangzhou 510275, People's Republic of China
| | - Tianzhi Huang
- College of Life Sciences, Zhejiang University, Hangzhou 310058, People's Republic of China
| | - Xiaobo Zhang
- College of Life Sciences, Zhejiang University, Hangzhou 310058, People's Republic of China.
| | - Jian-Guo He
- MOE Key Laboratory of Aquatic Product Safety/State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, 135 Xingang Road West, Guangzhou 510275, People's Republic of China; School of Marine Sciences, Sun Yat-Sen University, 135 Xingang Road West, Guangzhou 510275, People's Republic of China.
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23
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Deng L, Shang Y, Guo S, Liu C, Zhou L, Sun Y, Nie Y, Fan D, Lu Y, Guo X. Ran GTPase protein promotes metastasis and invasion in pancreatic cancer by deregulating the expression of AR and CXCR4. Cancer Biol Ther 2014; 15:1087-93. [PMID: 24840182 DOI: 10.4161/cbt.29217] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Ran, a member of the RasGTPase family, has been showed to function in diverse cellular processes of cancer. In the present study, we examined the effects of Ran on the cell motility in pancreatic cancer cells and explored the possible mechanism of Ran's function in the metastasis of pancreatic cancer. We demonstrated that the expression of Ran was remarkably higher in lymph lode metastases than in primary pancreatic cancer tissues. In the functional studies, stable knockdown of Ran by shRNA could efficiently inhibit the migration and invasion of pancreatic cancer cells both in vitro and in vivo. By PCR array, we analyzed the differences in the expression levels of metastasis-associated genes before and after the downregulation of Ran, and it was showed that the regulation of pancreatic cancer metastasis by Ran was partially mediated by AR and CXCR4. We further confirmed that AR and CXCR4 were significantly decreased following knockdown of Ran. These data indicated that Ran could regulate the invasion and metastasis of pancreatic cancer cells through AR and CXCR4.
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Affiliation(s)
- Lin Deng
- State Key Laboratory of Cancer Biology; Xijing Hospital of Digestive Diseases; Fourth Military Medical University; Xi'an, Shaanxi, PR China; Department of Oncology; Tangdu Hospital; Fourth Military Medical University; Xi'an, Shaanxi, PR China
| | - Yulong Shang
- State Key Laboratory of Cancer Biology; Xijing Hospital of Digestive Diseases; Fourth Military Medical University; Xi'an, Shaanxi, PR China
| | - Shikong Guo
- Department of Orthopedic Surgery; Orthopedics Oncology Institute of Chinese PLA; Tangdu Hospital; Fourth Military Medical University; Xi'an, Shaanxi, PR China
| | - Changhao Liu
- State Key Laboratory of Cancer Biology; Xijing Hospital of Digestive Diseases; Fourth Military Medical University; Xi'an, Shaanxi, PR China
| | - Lin Zhou
- State Key Laboratory of Cancer Biology; Xijing Hospital of Digestive Diseases; Fourth Military Medical University; Xi'an, Shaanxi, PR China
| | - Yi Sun
- State Key Laboratory of Cancer Biology; Xijing Hospital of Digestive Diseases; Fourth Military Medical University; Xi'an, Shaanxi, PR China
| | - Yongzhan Nie
- State Key Laboratory of Cancer Biology; Xijing Hospital of Digestive Diseases; Fourth Military Medical University; Xi'an, Shaanxi, PR China
| | - Daiming Fan
- State Key Laboratory of Cancer Biology; Xijing Hospital of Digestive Diseases; Fourth Military Medical University; Xi'an, Shaanxi, PR China
| | - Yuanyuan Lu
- State Key Laboratory of Cancer Biology; Xijing Hospital of Digestive Diseases; Fourth Military Medical University; Xi'an, Shaanxi, PR China
| | - Xuegang Guo
- State Key Laboratory of Cancer Biology; Xijing Hospital of Digestive Diseases; Fourth Military Medical University; Xi'an, Shaanxi, PR China
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24
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Cáceres-Gorriti KY, Carmona E, Barrès V, Rahimi K, Létourneau IJ, Tonin PN, Provencher D, Mes-Masson AM. RAN nucleo-cytoplasmic transport and mitotic spindle assembly partners XPO7 and TPX2 are new prognostic biomarkers in serous epithelial ovarian cancer. PLoS One 2014; 9:e91000. [PMID: 24625450 PMCID: PMC3953127 DOI: 10.1371/journal.pone.0091000] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Accepted: 02/06/2014] [Indexed: 01/25/2023] Open
Abstract
Purpose Epithelial ovarian cancer has the highest mortality rate of all gynecological malignancies. We have shown that high RAN expression strongly correlates with high-grade and poor patient survival in epithelial ovarian cancer. However, as RAN is a small GTPase involved in two main biological functions, nucleo-cytoplasmic transport and mitosis, it is still unknown which of these functions associate with poor prognosis. Methods To examine the biomarker value of RAN network components in serous epithelial ovarian cancer, protein expression of six specific RAN partners was analyzed by immunohistochemistry using a tissue microarray representing 143 patients associated with clinical parameters. The RAN GDP/GTP cycle was evaluated by the expression of RANBP1 and RCC1, the mitotic function by TPX2 and IMPβ, and the nucleo-cytoplasmic trafficking function by XPO7, XPOT and IMPβ. Results Based on Kaplan-Meier analyses, RAN, cytoplasmic XPO7 and TPX2 were significantly associated with poor overall patient survival, and RAN and TPX2 were associated with lower disease free survival in patients with high-grade serous carcinoma. Cox regression analysis revealed that RAN and TPX2 expression were independent prognostic factors for both overall and disease free survival, and that cytoplasmic XPO7 expression was a prognostic factor for overall patient survival. Conclusions In this systematic study, we show that RAN and two protein partners involved in its nucleo-cytoplasmic and mitotic functions (XPO7 and TPX2, respectively) can be used as biomarkers to stratify patients based on prognosis. In particular, we reported for the first time the clinical relevance of the exportin XPO7 and showed that TPX2 expression had the strongest prognostic value. These findings suggest that protein partners in each of RAN’s functions can discriminate between different outcomes in high-grade serous epithelial ovarian cancer patients. Furthermore, these proteins point to cellular processes that may ultimately be targeted to improve the survival in serous epithelial ovarian cancer.
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Affiliation(s)
- Katia Y. Cáceres-Gorriti
- Centre de Recherche du Centre Hospitalier de l’Université de Montréal (CRCHUM), Montreal, Canada
- Institut du Cancer de Montréal, Montreal, Canada
| | - Euridice Carmona
- Centre de Recherche du Centre Hospitalier de l’Université de Montréal (CRCHUM), Montreal, Canada
- Institut du Cancer de Montréal, Montreal, Canada
| | - Véronique Barrès
- Centre de Recherche du Centre Hospitalier de l’Université de Montréal (CRCHUM), Montreal, Canada
- Institut du Cancer de Montréal, Montreal, Canada
| | - Kurosh Rahimi
- Department of Pathology, Centre Hospitalier de l’Université de Montréal (CHUM), Montreal, Canada
| | - Isabelle J. Létourneau
- Centre de Recherche du Centre Hospitalier de l’Université de Montréal (CRCHUM), Montreal, Canada
- Institut du Cancer de Montréal, Montreal, Canada
| | - Patricia N. Tonin
- The Research Institute of the McGill University Health Centre, Montreal, Canada
- Department of Human Genetics, McGill University, Montreal, Canada
- Department of Medicine, McGill University, Montreal, Canada
| | - Diane Provencher
- Centre de Recherche du Centre Hospitalier de l’Université de Montréal (CRCHUM), Montreal, Canada
- Institut du Cancer de Montréal, Montreal, Canada
- Department of Obstetric-Gynecology, Université de Montréal, Montreal, Canada
- Department of Medicine, Université de Montréal, Montreal, Canada
| | - Anne-Marie Mes-Masson
- Centre de Recherche du Centre Hospitalier de l’Université de Montréal (CRCHUM), Montreal, Canada
- Institut du Cancer de Montréal, Montreal, Canada
- Department of Medicine, Université de Montréal, Montreal, Canada
- * E-mail:
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25
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Bernis C, Swift-Taylor B, Nord M, Carmona S, Chook YM, Forbes DJ. Transportin acts to regulate mitotic assembly events by target binding rather than Ran sequestration. Mol Biol Cell 2014; 25:992-1009. [PMID: 24478460 PMCID: PMC3967982 DOI: 10.1091/mbc.e13-08-0506] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Transportin-specific molecular tools are used to show that the mitotic cell contains importin β and transportin “global positioning system” pathways that are mechanistically parallel. Transportin works to control where the spindle, nuclear membrane, and nuclear pores are formed by directly affecting assembly factor function. The nuclear import receptors importin β and transportin play a different role in mitosis: both act phenotypically as spatial regulators to ensure that mitotic spindle, nuclear membrane, and nuclear pore assembly occur exclusively around chromatin. Importin β is known to act by repressing assembly factors in regions distant from chromatin, whereas RanGTP produced on chromatin frees factors from importin β for localized assembly. The mechanism of transportin regulation was unknown. Diametrically opposed models for transportin action are as follows: 1) indirect action by RanGTP sequestration, thus down-regulating release of assembly factors from importin β, and 2) direct action by transportin binding and inhibiting assembly factors. Experiments in Xenopus assembly extracts with M9M, a superaffinity nuclear localization sequence that displaces cargoes bound by transportin, or TLB, a mutant transportin that can bind cargo and RanGTP simultaneously, support direct inhibition. Consistently, simple addition of M9M to mitotic cytosol induces microtubule aster assembly. ELYS and the nucleoporin 107–160 complex, components of mitotic kinetochores and nuclear pores, are blocked from binding to kinetochores in vitro by transportin, a block reversible by M9M. In vivo, 30% of M9M-transfected cells have spindle/cytokinesis defects. We conclude that the cell contains importin β and transportin “global positioning system”or “GPS” pathways that are mechanistically parallel.
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Affiliation(s)
- Cyril Bernis
- Section of Cell and Developmental Biology, Division of Biological Sciences 0347, University of California-San Diego, La Jolla, CA 92093-0347 Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9041
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26
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Wakil SM, Ramzan K, Abuthuraya R, Hagos S, Al-Dossari H, Al-Omar R, Murad H, Chedrawi A, Al-Hassnan ZN, Finsterer J, Bohlega S. Infantile-onset ascending hereditary spastic paraplegia with bulbar involvement due to the novel ALS2 mutation c.2761C>T. Gene 2013; 536:217-20. [PMID: 24315819 DOI: 10.1016/j.gene.2013.11.043] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Revised: 11/14/2013] [Accepted: 11/18/2013] [Indexed: 11/17/2022]
Abstract
Recessive mutations in the alsin gene cause three clinically distinct motor neuron diseases: juvenile amyotrophic lateral sclerosis (ALS2), juvenile primary lateral sclerosis (JPLS) and infantile-onset ascending hereditary spastic paraplegia (IAHSP). A total of 23 different ALS2 mutations have been described for the three disorders so far. Most of these mutations result in a frameshift leading to a premature truncation of the alsin protein. We report the novel ALS2 truncating mutation c.2761C>T; p.R921X detected by homozygosity mapping and sequencing in two infants affected by IAHSP with bulbar involvement. The mutation c.2761C>T resides in the pleckstrin domain, a characteristic segment of guanine nucleotide exchange factors of the Rho GTPase family, which is involved in the overall neuronal development or maintenance. This study highlights the importance of using homozygosity mapping combined with candidate gene analysis to identify the underlying genetic defect as in this Saudi consanguineous family.
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Affiliation(s)
- Salma M Wakil
- Department of Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia.
| | - Khushnooda Ramzan
- Department of Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Rula Abuthuraya
- Department of Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Samya Hagos
- Department of Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Haya Al-Dossari
- Department of Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Rana Al-Omar
- Department of Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Hatem Murad
- Department of Neurosciences, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Aziza Chedrawi
- Department of Neurosciences, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Zuhair N Al-Hassnan
- Department of Medical Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | | | - Saeed Bohlega
- Department of Neurosciences, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
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27
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Ye T, Zhang X. Involvement of Ran in the regulation of phagocytosis against virus infection in S2 cells. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2013; 41:491-497. [PMID: 23916491 DOI: 10.1016/j.dci.2013.07.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Revised: 07/22/2013] [Accepted: 07/24/2013] [Indexed: 06/02/2023]
Abstract
Phagocytosis plays important roles in innate and adaptive immunity in animals. Some small G proteins are found to be related to phagocytosis. However, the Ran GTPase has not been intensively characterized in immunity. In this paper, the sequence analysis showed that the Ran was highly conserved in animals, suggesting that its function was preserved during animal evolution. The results showed that Ran was upregulated in S2 cells in response to DCV infection. It was further revealed that the antiviral phagocytosis could be mediated by Ran in S2 cells. By comparison with the early marker and late marker of phagosomes, the results showed that the Ran protein played an essential role at the early stage of phagocytosis or throughout the entire phagocytic process. Therefore our findings enlarged our limited knowledge about the phagocytosis regulation by small G proteins concerning to the nucleus.
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Affiliation(s)
- Ting Ye
- Key Laboratory of Animal Virology of Ministry of Agriculture and College of Life Sciences and Key Laboratory of Conservation Biology for Endangered Wildlife of the Ministry of Education, Zhejiang University, Hangzhou 310058, People's Republic of China; College of Life Sciences, Zhejiang Sci-Tech University, Hangzhou 310018, People's Republic of China
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28
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Deng L, Lu Y, Zhao X, Sun Y, Shi Y, Fan H, Liu C, Zhou J, Nie Y, Wu K, Fan D, Guo X. Ran GTPase protein promotes human pancreatic cancer proliferation by deregulating the expression of Survivin and cell cycle proteins. Biochem Biophys Res Commun 2013; 440:322-9. [PMID: 24076388 DOI: 10.1016/j.bbrc.2013.09.079] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Accepted: 09/15/2013] [Indexed: 12/20/2022]
Abstract
Ran, a member of the Ras GTPase family, has important roles in nucleocytoplasmic transport. Herein, we detected Ran expression in pancreatic cancer and explored its potential role on tumour progression. Overexpressed Ran in pancreatic cancer tissues was found highly correlated with the histological grade. Downregulation of Ran led to significant suppression of cell proliferation, cell cycle arrest at the G1/S phase and induction of apoptosis. In vivo studies also validated that result. Further studies revealed that those effects were at least partly mediated by the downregulation of Cyclin A, Cyclin D1, Cyclin E, CDK2, CDK4, phospho-Rb and Survivin proteins and up regulation of cleaved Caspase-3.
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Affiliation(s)
- Lin Deng
- State Key Laboratory of Cancer Biology, Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi'an, Shaanxi 710032, China; Department of Oncology, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi 710038, China
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29
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Edinger D, Kläger R, Troiber C, Dohmen C, Wagner E. Gene silencing and antitumoral effects of Eg5 or Ran siRNA oligoaminoamide polyplexes. Drug Deliv Transl Res 2013; 4:84-95. [DOI: 10.1007/s13346-013-0146-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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30
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Pfaff KL, King RW. Determinants of human cyclin B1 association with mitotic chromosomes. PLoS One 2013; 8:e59169. [PMID: 23505570 PMCID: PMC3594322 DOI: 10.1371/journal.pone.0059169] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2012] [Accepted: 02/13/2013] [Indexed: 12/28/2022] Open
Abstract
Cyclin B1–CDK1 activity is essential for mitotic entry, but questions remain regarding how the activity of this kinase is spatially regulated. Previous studies showed that the cyclin B1 subunit localizes to several compartments of a mitotic cell, including the centrosomes, mitotic spindle, kinetochores and chromosomes via distinct sequence elements. Mitotic chromosome association occurs through the unstructured N-terminal domain of cyclin B1 and is independent of CDK1 binding. Here, we use live cell imaging of human cyclin B1 fused to GFP to precisely define the sequence elements within cyclin B1 that mediate its association with condensed mitotic chromosomes. We find that a short, evolutionarily conserved N-terminal motif is required for cyclin B1 to localize to mitotic chromosomes. We further reveal a role for arginine residues within and near the destruction box sequence in the chromosome association of cyclin B1. Additionally, our data suggest that sequences further downstream in cyclin B1, such as the cytoplasmic retention sequence and the cyclin box, may negatively modulate chromosome association. Because multiple basic residues are required for cyclin B1 association with mitotic chromosomes, electrostatic interactions with DNA may facilitate cyclin B1 localization to chromosomes.
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Affiliation(s)
- Kathleen L. Pfaff
- Harvard Medical School Department of Cell Biology, Boston, Massachusetts, United States of America
| | - Randall W. King
- Harvard Medical School Department of Cell Biology, Boston, Massachusetts, United States of America
- * E-mail:
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31
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RamanaRao MV, Weindorf D, Breitenbeck G, Baisakh N. Differential expression of the transcripts of Spartina alterniflora Loisel (smooth cordgrass) induced in response to petroleum hydrocarbon. Mol Biotechnol 2012; 51:18-26. [PMID: 21732077 DOI: 10.1007/s12033-011-9436-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Petroleum hydrocarbons (PHC) in soil are potentially toxic to plants and exert negative effect on the environment and human health. To understand the effect of PHC on the gene expression profile of a wetland plant Spartina alterniflora in the coastal Louisiana, plants were subject up to 40% PHC under greenhouse conditions. The plants exposed to PHC showed 21% reduction of leaf total chlorophyll after 2 weeks of stress. Using 20 annealing control primers, 28 differentially expressing genes (DEGs) were identified in leaf and root tissues of S. alterniflora in response to PHC stress. Eleven of these 28 DEGs had role in either molecular function (chlorophyll a-b binding protein, HSP70, NADH, RAN1-binding protein, and RNA-binding protein), biological processes (cell wall protein, nucelosome/chromatin assembly factor) or cellular function (30 S ribosomal protein). This indicated that genes in different regulatory pathways of S. alterniflora were involved in response to PHC. All DEGs showed reduced transcript accumulation in root under oil stress, whereas they showed up- or down-regulation in their transcript abundance in leaf depending on the concentration of the PHC. The genes identified through this study could be used in the genetic screen of S. alterniflora for resistance to PHC.
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Affiliation(s)
- Mangu Venkata RamanaRao
- School of Plant, Environmental, and Soil Sciences, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, USA
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32
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Labonté B, Suderman M, Maussion G, Navaro L, Yerko V, Mahar I, Bureau A, Mechawar N, Szyf M, Meaney MJ, Turecki G. Genome-wide epigenetic regulation by early-life trauma. ACTA ACUST UNITED AC 2012; 69:722-31. [PMID: 22752237 DOI: 10.1001/archgenpsychiatry.2011.2287] [Citation(s) in RCA: 289] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
CONTEXT Our genome adapts to environmental influences, in part through epigenetic mechanisms, including DNA methylation. Variations in the quality of the early environment are associated with alterations in DNA methylation in rodents, and recent data suggest similar processes in humans in response to early-life adversity. OBJECTIVE To determine genome-wide DNA methylation alterations induced by early-life trauma. DESIGN Genome-wide study of promoter methylation in individuals with severe abuse during childhood. PATIENTS, SETTING, AND MAIN OUTCOME MEASURES: Promoter DNA methylation levels were profiled using methylated DNA immunoprecipitation followed by microarray hybridization in hippocampal tissue from 41 French-Canadian men (25 with a history of severe childhood abuse and 16 control subjects). Methylation profiles were compared with corresponding genome-wide gene expression profiles obtained by messenger RNA microarrays. Methylation differences between groups were validated on neuronal and nonneuronal DNA fractions isolated by fluorescence-assisted cell sorting. Functional consequences of site-specific promoter methylation were assessed by luciferase assays. RESULTS We identified 362 differentially methylated promoters in individuals with a history of abuse compared with controls. Among these promoters, 248 showed hypermethylation and 114 demonstrated hypomethylation. Validation and site-specific quantification of DNA methylation in the 5 most hypermethylated gene promoters indicated that methylation differences occurred mainly in the neuronal cellular fraction. Genes involved in cellular/neuronal plasticity were among the most significantly differentially methylated, and, among these, Alsin (ALS2) was the most significant finding. Methylated ALS2 constructs mimicking the methylation state in samples from abused suicide completers showed decreased promoter transcriptional activity associated with decreased hippocampal expression of ALS2 variants. CONCLUSION Childhood adversity is associated with epigenetic alterations in the promoters of several genes in hippocampal neurons.
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Affiliation(s)
- Benoit Labonté
- McGill Group for Suicide Studies, Douglas Mental Health University Institute, Verdun, QC, Canada
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33
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Fan H, Lu Y, Qin H, Zhou Y, Gu Y, Zhou J, Wang X, Fan D. High Ran level is correlated with poor prognosis in patients with colorectal cancer. Int J Clin Oncol 2012; 18:856-63. [PMID: 22956174 DOI: 10.1007/s10147-012-0465-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Accepted: 07/30/2012] [Indexed: 12/15/2022]
Abstract
BACKGROUND The Ras-like nuclear protein (Ran) is involved in the regulation of nuclear transport, microtubule nucleation and dynamics, and spindle assembly. Its fundamental function is nucleocytoplasmic transport of RNA and proteins. The expression and potential role of Ran in colorectal cancer (CRC) remain unclear. The aim of this study was to investigate the relationship between Ran expression and CRC characteristics. The potential role of Ran as a prognostic indicator was also evaluated. METHODS We used immunohistochemistry and western blotting to detect Ran expression in 287 CRC tissues. The relationships between Ran expression and clinicopathological characteristics and overall survival rate were statistically analyzed. RESULTS CRC tissues had significantly higher Ran expression than normal colorectal epithelial cells. Ran was positively correlated with depth of invasion, lymph node metastases, distant metastases, tumor differentiation, and tumor-node-metastasis stage. However, no correlation was found between Ran expression and patient age or sex. The overall survival rate was consistently and significantly lower in patients with Ran-positive tumors than in those with Ran-negative tumors. CONCLUSION Our findings emphasize the important role of Ran in differentiation, disease stage, and metastasis in human CRC. Ran may play an important role in the development of CRC and may serve as a novel prognostic indicator of CRC.
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Affiliation(s)
- Hongwei Fan
- State Key Laboratory of Cancer Biology, Xijing Hospital of Digestive Diseases, Fourth Military Medical University, 127 West Changle Road, Xi'an, Shaanxi, 710032, China
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Luo M, Zhang QC, Lu ZG. [An efficient high-throughput screening assay against nuclear transport]. YI CHUAN = HEREDITAS 2012; 34:927-34. [PMID: 22805220 DOI: 10.3724/sp.j.1005.2012.00927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Nuclear transport, an essential cellular process of eukaryotic cells, plays critical roles in differentiation , development, as well as viral disease and oncogenesis, making the small molecules that target this process very intriguing not only in fundamental research but also in disease treatment. However, only one compound, Leptomycin B, is commercially available to inhibit nuclear transport. Therefore, it will be a great advantage to establish an assay that targets the whole nuclear transport pathway for screening and obtaining small molecule that regulates nuclear transport. In this study, we established an efficient nuclear transport assay based on the reconstitution of GFP by NZGFP and CZGFP. We constructed NZGFP-NES and CZGFP-NLS, making them locate in cytoplasm and nucleus separately. Their distribution will be changed when nuclear transport is interfered, resulting in co-localization of NZGFP-NES and CZGFP-NLS and subsequent reconstitution of fluorescent GFP. The inhibiting effect of Leptomycin B on nuclear transport can be sensitively detected by NZGFP-NES/CZGFP-NLS report system, providing an efficient assay for high-throughput screening of small molecule against nuclear transport.
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Affiliation(s)
- Min Luo
- ShenzhenCenter for Disease Control and Prevention, Shenzhen 518055, China.
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35
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Huang JG, Gao XJ, Li QZ, Lu LM, Liu R, Luo CC, Wang JL, Bin Q, Jin X. Proteomic analysis of the nuclear phosphorylated proteins in dairy cow mammary epithelial cells treated with estrogen. In Vitro Cell Dev Biol Anim 2012; 48:449-57. [PMID: 22806971 DOI: 10.1007/s11626-012-9531-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Accepted: 06/21/2012] [Indexed: 01/27/2023]
Abstract
Estrogen regulates a variety of physiological processes, including mammary gland growth, morphogenesis of the mammary gland, proliferation and differentiation, and elevating the expression of milk proteins. Many nuclear phosphorylated proteins such as pStat5 and mTOR regulate milk protein synthesis. But the detail of milk protein synthesis controlled at the transcript level and posttranslational level is not well-known. To contribute to the understanding of the molecular mechanism underlying estrogen action on the dairy cow mammary epithelial cells (DCMECs), nuclear phosphorylated proteins regulated by estrogen in DCMECs were identified. Two-dimensional gel electrophoresis and matrix-assisted laser desorption/ionization/time of flight mass spectrometry were used to identify the changes of nuclear phosphorylated proteins in DCMECs treated with estrogen. Seven proteins were identified differentially up-expressed in DCMECs after 24-h estrogen exposure: including glycyl-tRNA synthetase, previously reported in milk protein synthesis of DCMECs, belonging to the class-II aminoacyl-tRNA synthetase family; proteins involved in other cellular functions, such as translation initiation factors, GTP-binding nuclear proteins, heat-shock proteins, and proteins belonging to ubiquitin-proteasome system. This screening reveals that estrogen influences the levels of nuclear phosphorylated proteins of DCMECs which opens new avenue for the study of the molecular mechanism linking to milk synthesis.
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Affiliation(s)
- Jian-Guo Huang
- The Key Laboratory of Dairy Science of Education Ministry, Northeast Agricultural University, Xiangfang District, Harbin, Heilongjiang Province, China
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Proteome analysis on lethal effect of l 2 in the sex-linked balanced lethal strains of silkworm, Bombyx mori. BIOTECHNOL BIOPROC E 2012. [DOI: 10.1007/s12257-012-0006-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Specific Cooperation Between Imp-α2 and Imp-β/Ketel in Spindle Assembly During Drosophila Early Nuclear Divisions. G3-GENES GENOMES GENETICS 2012; 2:1-14. [PMID: 22384376 PMCID: PMC3276186 DOI: 10.1534/g3.111.001073] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Accepted: 10/14/2011] [Indexed: 12/22/2022]
Abstract
The multifunctional factors Imp-α and Imp-β are involved in nuclear protein import, mitotic spindle dynamics, and nuclear membrane formation. Furthermore, each of the three members of the Imp-α family exerts distinct tasks during development. In Drosophila melanogaster, the imp-α2 gene is critical during oogenesis for ring canal assembly; specific mutations, which allow oogenesis to proceed normally, were found to block early embryonic mitosis. Here, we show that imp-α2 and imp-β genetically interact during early embryonic development, and we characterize the pattern of defects affecting mitosis in embryos laid by heterozygous imp-α2(D14) and imp-β(KetRE34) females. Embryonic development is arrested in these embryos but is unaffected in combinations between imp-β(KetRE34) and null mutations in imp-α1 or imp-α3. Furthermore, the imp-α2(D14)/imp-β(KetRE34) interaction could only be rescued by an imp-α2 transgene, albeit not imp-α1 or imp-α3, showing the exclusive imp-α2 function with imp-β. Use of transgenes carrying modifications in the major Imp-α2 domains showed the critical requirement of the nuclear localization signal binding (NLSB) site in this process. In the mutant embryos, we found metaphase-arrested mitoses made of enlarged spindles, suggesting an unrestrained activity of factors promoting spindle assembly. In accordance with this, we found that Imp-β(KetRE34) and Imp-β(KetD) bind a high level of RanGTP/GDP, and a deletion decreasing RanGTP level suppresses the imp-β(KetRE34) phenotype. These data suggest that a fine balance among Imp-α2, Imp-β, RanGTP, and the NLS cargos is critical for mitotic progression during early embryonic development.
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Boruc J, Zhou X, Meier I. Dynamics of the plant nuclear envelope and nuclear pore. PLANT PHYSIOLOGY 2012; 158:78-86. [PMID: 21949214 PMCID: PMC3252082 DOI: 10.1104/pp.111.185256] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
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Zeng F, Tian Y, Shi S, Wu Q, Liu S, Zheng H, Yue L, Li Y. Identification of mouse MARVELD1 as a microtubule associated protein that inhibits cell cycle progression and migration. Mol Cells 2011; 31:267-74. [PMID: 21347699 PMCID: PMC3932696 DOI: 10.1007/s10059-011-0037-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2010] [Revised: 12/15/2010] [Accepted: 12/24/2010] [Indexed: 12/20/2022] Open
Abstract
MARVEL domain-containing 1 (MARVELD1) is a newly identified nuclear protein; however its function has not been clear until now. Here, we report that mouse MARVELD1 (mMARVELD1), which is highly conserved between mice and humans, exhibits cell cycle-dependent cellular localization. In NIH3T3 cells, MARVELD1 was observed in the nucleus and at the perinuclear region during interphase, but was localized at the mitotic spindle and midbody at metaphase, and a significant fraction of mMARVELD1 translocated to the plasma membrane during anaphase. In addition, treatment of cells with colchicine, a microtubule-depolymerizing agent, resulted in translocation of mMARVELD1 to the plasma membrane, and association of mMARVELD1 and α-tubulin was confirmed by co-immunoprecipitation. Finally, overexpression of mMARVELD1 resulted in a remarkable inhibition of cell proliferation, G1-phase arrest, and reduced cell migration. These findings indicate that mMARVELD1 is a microtubule-associated protein that plays an important role in cell cycle progression and migration.
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Affiliation(s)
- Fanli Zeng
- Department of Life Science and Engineering, Harbin Institute of Technology, Harbin 150001, People’s Republic of China
| | - Yanyan Tian
- Department of Life Science and Engineering, Harbin Institute of Technology, Harbin 150001, People’s Republic of China
| | - Shuliang Shi
- Department of Life Science and Engineering, Harbin Institute of Technology, Harbin 150001, People’s Republic of China
| | - Qiong Wu
- Department of Life Science and Engineering, Harbin Institute of Technology, Harbin 150001, People’s Republic of China
| | - Shanshan Liu
- Department of Life Science and Engineering, Harbin Institute of Technology, Harbin 150001, People’s Republic of China
| | - Hongxia Zheng
- Department of Life Science and Engineering, Harbin Institute of Technology, Harbin 150001, People’s Republic of China
| | - Lei Yue
- The Academy of Fundamental and Interdisciplinary Science, Harbin Institute of Technology, Harbin 150001, People’s Republic of China
| | - Yu Li
- Department of Life Science and Engineering, Harbin Institute of Technology, Harbin 150001, People’s Republic of China
- The Academy of Fundamental and Interdisciplinary Science, Harbin Institute of Technology, Harbin 150001, People’s Republic of China
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Oka M, Asally M, Yasuda Y, Ogawa Y, Tachibana T, Yoneda Y. The mobile FG nucleoporin Nup98 is a cofactor for Crm1-dependent protein export. Mol Biol Cell 2010; 21:1885-96. [PMID: 20375145 PMCID: PMC2877646 DOI: 10.1091/mbc.e09-12-1041] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2009] [Revised: 03/26/2010] [Accepted: 03/29/2010] [Indexed: 12/18/2022] Open
Abstract
Nup98 is a mobile nucleoporin that forms distinct dots in the nucleus, and, although a role for Nup98 in nuclear transport has been suggested, its precise function remains unclear. Here, we show that Nup98 plays an important role in Crm1-mediated nuclear protein export. Nuclear, but not cytoplasmic, dots of EGFP-tagged Nup98 disappeared rapidly after cell treatment with leptomycin B, a specific inhibitor of the nuclear export receptor, Crm1. Mutational analysis demonstrated that Nup98 physically and functionally interacts with Crm1 in a RanGTP-dependent manner through its N-terminal phenylalanine-glycine (FG) repeat region. Moreover, the activity of the Nup98-Crm1 complex was modulated by RanBP3, a known cofactor for Crm1-mediated nuclear export. Finally, cytoplasmic microinjection of anti-Nup98 inhibited the Crm1-dependent nuclear export of proteins, concomitant with the accumulation of anti-Nup98 in the nucleus. These results clearly demonstrate that Nup98 functions as a novel shuttling cofactor for Crm1-mediated nuclear export in conjunction with RanBP3.
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Affiliation(s)
- Masahiro Oka
- *Biomolecular Dynamics Group, Graduate School of Frontier Biosciences
- Department of Biochemistry, Graduate School of Medicine, Osaka University, and
- Japan Science and Technology Corporation (JST), Core Research for Evolution Science and Technology (CREST), Osaka University, Suita, Osaka 565-0871, Japan; and
| | - Munehiro Asally
- *Biomolecular Dynamics Group, Graduate School of Frontier Biosciences
| | - Yoshinari Yasuda
- *Biomolecular Dynamics Group, Graduate School of Frontier Biosciences
| | - Yutaka Ogawa
- *Biomolecular Dynamics Group, Graduate School of Frontier Biosciences
| | - Taro Tachibana
- Department of Bioengineering, Graduate School of Engineering, Osaka City University, Osaka 558-8585, Japan
| | - Yoshihiro Yoneda
- *Biomolecular Dynamics Group, Graduate School of Frontier Biosciences
- Department of Biochemistry, Graduate School of Medicine, Osaka University, and
- Japan Science and Technology Corporation (JST), Core Research for Evolution Science and Technology (CREST), Osaka University, Suita, Osaka 565-0871, Japan; and
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Yuksel B, Memon AR. Legume small GTPases and their role in the establishment of symbiotic associations with Rhizobium spp. PLANT SIGNALING & BEHAVIOR 2009; 4:257-60. [PMID: 19794839 PMCID: PMC2664483 DOI: 10.4161/psb.4.4.7868] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2009] [Accepted: 01/16/2009] [Indexed: 05/03/2023]
Abstract
Small GTP-binding genes act as molecular switches regulating myriad of cellular processes including vesicle-mediated intracellular trafficking, signal transduction, cytoskeletal reorganization and cell division in plants and animals. Even though these genes are well conserved both functionally and sequentially across whole Eukaryotae, occasional lineage-specific diversification in some plant species in terms of both functional and expressional characteristics have been reported. Hence, comparative phyletic and correlative functional analyses of legume small GTPases homologs with the genes from other Metazoa and Embryophyta species would be very beneficial for gleaning out the small GTPases that could have specialized in legume-specific processes; e.g., nodulation. The completion of genome sequences of two model legumes, Medicago truncatula and Lotus japonicus will significantly improve our knowledge about mechanism of biological processes taking place in legume-rhizobia symbiotic associations. Besides, the need for molecular switches coordinating busy cargo-trafficking between symbiosis partners would suggest a possible subfunctionalization of small GTPases in Fabaceae for these functions. Therefore, more detailed investigation into the functional characteristics of legume small GTPases would be helpful for the illumination of the events initialized with the perception of bacteria by host, followed by the formation of infection thread and the engulfment of rhizobial bacteria, and end with the senescence of nitrogen-fixing organelles, nodules. In summary, a more thorough functional and evolutionary characterization of small GTPases across the main lineages of Embryophyta is significant for better comprehension of evolutionary history of Plantae, that is because, these genes are associated with multitude of vital biological processes including organogenesis.
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Affiliation(s)
- Bayram Yuksel
- The Scientific and Technological Research Council of Turkey (TUBITAK), Marmara Research Center, Genetic Engineering and Biotechnology Institute, Plant Molecular Biology Laboratory, Gebze, Kocaeli, Turkey.
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Silk AD, Holland AJ, Cleveland DW. Requirements for NuMA in maintenance and establishment of mammalian spindle poles. ACTA ACUST UNITED AC 2009; 184:677-90. [PMID: 19255246 PMCID: PMC2686415 DOI: 10.1083/jcb.200810091] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Microtubules of the mitotic spindle in mammalian somatic cells are focused at spindle poles, a process thought to include direct capture by astral microtubules of kinetochores and/or noncentrosomally nucleated microtubule bundles. By construction and analysis of a conditional loss of mitotic function allele of the nuclear mitotic apparatus (NuMA) protein in mice and cultured primary cells, we demonstrate that NuMA is an essential mitotic component with distinct contributions to the establishment and maintenance of focused spindle poles. When mitotic NuMA function is disrupted, centrosomes provide initial focusing activity, but continued centrosome attachment to spindle fibers under tension is defective, and the maintenance of focused kinetochore fibers at spindle poles throughout mitosis is prevented. Without centrosomes and NuMA, initial establishment of spindle microtubule focusing completely fails. Thus, NuMA is a defining feature of the mammalian spindle pole and functions as an essential tether linking bulk microtubules of the spindle to centrosomes.
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Affiliation(s)
- Alain D Silk
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA
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A Rac GTPase-activating protein, MgcRacGAP, is a nuclear localizing signal-containing nuclear chaperone in the activation of STAT transcription factors. Mol Cell Biol 2009; 29:1796-813. [PMID: 19158271 DOI: 10.1128/mcb.01423-08] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In addition to their pleiotropic functions under physiological conditions, transcription factors STAT3 and STAT5 also have oncogenic activities, but how activated STATs are transported to the nucleus has not been fully understood. Here we show that an MgcRacGAP mutant lacking its nuclear localizing signal (NLS) blocks nuclear translocation of p-STATs both in vitro and in vivo. Unlike wild-type MgcRacGAP, this mutant did not promote complex formation of phosphorylated STATs (p-STATs) with importin alpha in the presence of GTP-bound Rac1, suggesting that MgcRacGAP functions as an NLS-containing nuclear chaperone. We also demonstrate that mutants of STATs lacking the MgcRacGAP binding site (the strand betab) are hardly tyrosine phosphorylated after cytokine stimulation. Intriguingly, mutants harboring small deletions in the C'-adjacent region (betab-betac loop region) of the strand betab became constitutively active with the enhanced binding to MgcRacGAP. The molecular basis of this phenomenon will be discussed, based on the computer-assisted tertiary structure models of STAT3. Thus, MgcRacGAP functions as both a critical mediator of STAT's tyrosine phosphorylation and an NLS-containing nuclear chaperone of p-STATs.
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Yuksel B, Memon AR. Comparative phylogenetic analysis of small GTP-binding genes of model legume plants and assessment of their roles in root nodules. JOURNAL OF EXPERIMENTAL BOTANY 2008; 59:3831-44. [PMID: 18849296 PMCID: PMC2576638 DOI: 10.1093/jxb/ern223] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2008] [Revised: 07/17/2008] [Accepted: 08/06/2008] [Indexed: 05/03/2023]
Abstract
Small GTP-binding genes play an essential regulatory role in a multitude of cellular processes such as vesicle-mediated intracellular trafficking, signal transduction, cytoskeletal organization, and cell division in plants and animals. Medicago truncatula and Lotus japonicus are important model plants for studying legume-specific biological processes such as nodulation. The publicly available online resources for these plants from websites such as http://www.ncbi.nih.gov, http://www.medicago.org, http://www.tigr.org, and related sites were searched to collect nucleotide sequences that encode GTP-binding protein homologues. A total of 460 small GTPase sequences from several legume species including Medicago and Lotus, Arabidopsis, human, and yeast were phyletically analysed to shed light on the evolution and functional characteristics of legume-specific homologues. One of the main emphases of this study was the elucidation of the possible involvement of some members of small GTPase homologues in the establishment and maintenance of symbiotic associations in root nodules of legumes. A high frequency of vesicle-mediated trafficking in nodules led to the idea of a probable subfunctionalization of some members of this family in legumes. As a result of the analyses, a group of 10 small GTPases that are likely to be mainly expressed in nodules was determined. The sequences determined as a result of this study could be used in more detailed molecular genetic analyses such as creation of RNA interference silencing mutants for further clarification of the role of GTPases in nodulation. This study will also assist in furthering our understanding of the evolutionary history of small GTPases in legume species.
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Affiliation(s)
- Bayram Yuksel
- Plant Molecular Biology Laboratory, Genetic Engineering and Biotechnology Institute, Marmara Research Center, TUBITAK, PO Box 21, 41400, Gebze, Kocaeli, Turkey.
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Neuber A, Franke J, Wittstruck A, Schlenstedt G, Sommer T, Stade K. Nuclear export receptor Xpo1/Crm1 is physically and functionally linked to the spindle pole body in budding yeast. Mol Cell Biol 2008; 28:5348-58. [PMID: 18573877 PMCID: PMC2519715 DOI: 10.1128/mcb.02043-07] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2007] [Revised: 12/28/2007] [Accepted: 06/16/2008] [Indexed: 01/13/2023] Open
Abstract
The spindle pole body (SPB) represents the microtubule organizing center in the budding yeast Saccharomyces cerevisiae. It is a highly structured organelle embedded in the nuclear membrane, which is required to anchor microtubules on both sides of the nuclear envelope. The protein Spc72, a component of the SPB, is located at the cytoplasmic face of this organelle and serves as a receptor for the gamma-tubulin complex. In this paper we show that it is also a binding partner of the nuclear export receptor Xpo1/Crm1. Xpo1 binds its cargoes in a Ran-dependent fashion via a short leucine-rich nuclear export signal (NES). We show that binding of Spc72 to Xpo1 depends on Ran-GTP and a functional NES in Spc72. Mutations in this NES have severe consequences for mitotic spindle morphology in vivo. This is also the case for xpo1 mutants, which show a reduction in cytoplasmic microtubules. In addition, we find a subpopulation of Xpo1 localized at the SPB. Based on these data, we propose a functional link between Xpo1 and the SPB and discuss a role for this exportin in spindle biogenesis in budding yeast.
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Affiliation(s)
- Anja Neuber
- Max Delbrück Centrum für Molekulare Medizin, Robert Rössle Str. 10, 13092 Berlin, Germany
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Sepp KJ, Hong P, Lizarraga SB, Liu JS, Mejia LA, Walsh CA, Perrimon N. Identification of neural outgrowth genes using genome-wide RNAi. PLoS Genet 2008; 4:e1000111. [PMID: 18604272 PMCID: PMC2435276 DOI: 10.1371/journal.pgen.1000111] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2007] [Accepted: 05/28/2008] [Indexed: 12/13/2022] Open
Abstract
While genetic screens have identified many genes essential for neurite outgrowth, they have been limited in their ability to identify neural genes that also have earlier critical roles in the gastrula, or neural genes for which maternally contributed RNA compensates for gene mutations in the zygote. To address this, we developed methods to screen the Drosophila genome using RNA-interference (RNAi) on primary neural cells and present the results of the first full-genome RNAi screen in neurons. We used live-cell imaging and quantitative image analysis to characterize the morphological phenotypes of fluorescently labelled primary neurons and glia in response to RNAi-mediated gene knockdown. From the full genome screen, we focused our analysis on 104 evolutionarily conserved genes that when downregulated by RNAi, have morphological defects such as reduced axon extension, excessive branching, loss of fasciculation, and blebbing. To assist in the phenotypic analysis of the large data sets, we generated image analysis algorithms that could assess the statistical significance of the mutant phenotypes. The algorithms were essential for the analysis of the thousands of images generated by the screening process and will become a valuable tool for future genome-wide screens in primary neurons. Our analysis revealed unexpected, essential roles in neurite outgrowth for genes representing a wide range of functional categories including signalling molecules, enzymes, channels, receptors, and cytoskeletal proteins. We also found that genes known to be involved in protein and vesicle trafficking showed similar RNAi phenotypes. We confirmed phenotypes of the protein trafficking genes Sec61alpha and Ran GTPase using Drosophila embryo and mouse embryonic cerebral cortical neurons, respectively. Collectively, our results showed that RNAi phenotypes in primary neural culture can parallel in vivo phenotypes, and the screening technique can be used to identify many new genes that have important functions in the nervous system. Development and function of the brain requires the coordinated action of thousands of genes, and currently we understand the roles of only a small fraction of them. Recent advances in genomics, such as the sequencing of entire genomes and the discovery of RNA-interference as a means of testing the effects of gene loss, have opened up the possibility to systematically analyze the function of all known and predicted genes in an organism. Until now, this type of functional genomics approach has not been applied to the study of very complex cells, such as the brain's neurons, on a full-genome scale. In this work, we developed techniques to test all genes, one by one in a rapid manner, for their potential role in neuronal development using neurons isolated from fruit fly embryos. These results yielded a global perspective of what types of genes are necessary for brain development; importantly, they show that a large variety of genes can be studied in this way.
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Affiliation(s)
- Katharine J Sepp
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America.
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Tietze N, Pelisek J, Philipp A, Roedl W, Merdan T, Tarcha P, Ogris M, Wagner E. Induction of Apoptosis in Murine Neuroblastoma by Systemic Delivery of Transferrin-Shielded siRNA Polyplexes for Downregulation of Ran. Oligonucleotides 2008; 18:161-74. [DOI: 10.1089/oli.2008.0112] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Nicole Tietze
- Pharmaceutical Biotechnology, Department of Pharmacy, Center of Drug Research, LMU Munich, Germany
| | - Jaroslav Pelisek
- Pharmaceutical Biotechnology, Department of Pharmacy, Center of Drug Research, LMU Munich, Germany
| | - Alexander Philipp
- Pharmaceutical Biotechnology, Department of Pharmacy, Center of Drug Research, LMU Munich, Germany
| | - Wolfgang Roedl
- Pharmaceutical Biotechnology, Department of Pharmacy, Center of Drug Research, LMU Munich, Germany
| | - Thomas Merdan
- Departments of Advanced Drug Delivery, Abbott Laboratories, 100 Abbott Park Road, North Chicago IL
| | - Peter Tarcha
- Departments of Advanced Drug Delivery, Abbott Laboratories, 100 Abbott Park Road, North Chicago IL
| | - Manfred Ogris
- Pharmaceutical Biotechnology, Department of Pharmacy, Center of Drug Research, LMU Munich, Germany
| | - Ernst Wagner
- Pharmaceutical Biotechnology, Department of Pharmacy, Center of Drug Research, LMU Munich, Germany
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Abstract
The GTPase Ran has a key role in nuclear import and export, mitotic spindle assembly and nuclear envelope formation. The cycling of Ran between its GTP- and GDP-bound forms is catalyzed by the chromatin-bound guanine nucleotide exchange factor RCC1 and the cytoplasmic Ran GTPase-activating protein RanGAP. The result is an intracellular concentration gradient of RanGTP that equips eukaryotic cells with a ;genome-positioning system' (GPS). The binding of RanGTP to nuclear transport receptors (NTRs) of the importin beta superfamily mediates the effects of the gradient and generates further downstream gradients, which have been elucidated by fluorescence resonance energy transfer (FRET) imaging and computational modeling. The Ran-dependent GPS spatially directs many functions required for genome segregation by the mitotic spindle during mitosis. Through exportin 1, RanGTP recruits essential centrosome and kinetochore components, whereas the RanGTP-induced release of spindle assembly factors (SAFs) from importins activates SAFs to nucleate, bind and organize nascent spindle microtubules. Although a considerable fraction of cytoplasmic SAFs is active and RanGTP induces only partial further activation near chromatin, bipolar spindle assembly is robustly induced by cooperativity and positive-feedback mechanisms within the network of Ran-activated SAFs. The RanGTP gradient is conserved, although its roles vary among different cell types and species, and much remains to be learned regarding its functions.
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Affiliation(s)
- Petr Kalab
- Laboratory of Cell and Molecular Biology, National Cancer Institute, Bethesda, MD 20892-4256, USA.
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50
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Delmar VA, Chan RC, Forbes DJ. Xenopus importin beta validates human importin beta as a cell cycle negative regulator. BMC Cell Biol 2008; 9:14. [PMID: 18366719 PMCID: PMC2324082 DOI: 10.1186/1471-2121-9-14] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2007] [Accepted: 03/22/2008] [Indexed: 11/12/2022] Open
Abstract
Background Human importin beta has been used in all Xenopus laevis in vitro nuclear assembly and spindle assembly studies. This disconnect between species raised the question for us as to whether importin beta was an authentic negative regulator of cell cycle events, or a dominant negative regulator due to a difference between the human and Xenopus importin beta sequences. No Xenopus importin beta gene was yet identified at the time of those studies. Thus, we first cloned, identified, and tested the Xenopus importin beta gene to address this important mechanistic difference. If human importin beta is an authentic negative regulator then we would expect human and Xenopus importin beta to have identical negative regulatory effects on nuclear membrane fusion and pore assembly. If human importin beta acts instead as a dominant negative mutant inhibitor, we should then see no inhibitory effect when we added the Xenopus homologue. Results We found that Xenopus importin beta acts identically to its human counterpart. It negatively regulates both nuclear membrane fusion and pore assembly. Human importin beta inhibition was previously found to be reversible by Ran for mitotic spindle assembly and nuclear membrane fusion, but not nuclear pore assembly. During the present study, we observed that this differing reversibility varied depending on the presence or absence of a tag on importin beta. Indeed, when untagged importin beta, either human or Xenopus, was used, inhibition of nuclear pore assembly proved to be Ran-reversible. Conclusion We conclude that importin beta, human or Xenopus, is an authentic negative regulator of nuclear assembly and, presumably, spindle assembly. A difference in the Ran sensitivity between tagged and untagged importin beta in pore assembly gives us mechanistic insight into nuclear pore formation.
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Affiliation(s)
- Valerie A Delmar
- Section of Cell and Developmental Biology, Division of Biological Sciences 0347, University of California - San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0347, USA.
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