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Xu Y, Du N, Xu L, Zhao L, Fan T, Wei T, Pu Q, Liu S. Let-7 microRNA targets BmCentrin to modulate the development and functionality of the middle silk gland in the silkworm, Bombyx mori. INSECT SCIENCE 2024. [PMID: 38812265 DOI: 10.1111/1744-7917.13380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2024] [Revised: 04/16/2024] [Accepted: 04/24/2024] [Indexed: 05/31/2024]
Abstract
The silk gland of the silkworm Bombyx mori serves as a valuable model for investigating the morphological structure and physiological functions of organs. Previous studies have demonstrated the notable regulatory role of let-7 microRNA in the silk gland, but its specific molecular mechanism remains to be elucidated across different segments of this organ. In this study, we further investigated the functional mechanism of let-7 in the middle silk gland (MSG). The MSG of a let-7 knockout strain was analyzed using a combined proteomic and metabolomic technique, revealing the enrichment of differential proteins and metabolites in the DNA synthesis and energy metabolism pathways. BmCentrin was identified as a novel target gene of let-7 in the MSG, and its downregulation inhibited the proliferation of BmN4-SID1 cells, which is exactly opposite to the role of let-7 in these cells. CRISPR/Cas9 genome editing and transgenic technologies were employed to manipulate BmCentrin in the MSG. Knockout of BmCentrin led to severe MSG atrophy, whereas the overexpression of BmCentrin resulted in beaded MSG. Further measurements of these knockout or overexpression strains revealed significant changes in the expression levels of sericin protein genes, the weight of the cocoon and the mechanical properties of the silk. Investigating the biological role of BmCentrin in the silk gland offers valuable insights for elucidating the molecular mechanisms by which let-7 controls silk gland development and silk protein synthesis in the silkworm.
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Affiliation(s)
- Yankun Xu
- State Key Laboratory of Resource Insects, Southwest University, Chongqing, China
| | - Na Du
- State Key Laboratory of Resource Insects, Southwest University, Chongqing, China
| | - Lili Xu
- State Key Laboratory of Resource Insects, Southwest University, Chongqing, China
| | - Lu Zhao
- State Key Laboratory of Resource Insects, Southwest University, Chongqing, China
| | - Ting Fan
- State Key Laboratory of Resource Insects, Southwest University, Chongqing, China
| | - Tianqi Wei
- State Key Laboratory of Resource Insects, Southwest University, Chongqing, China
| | - Qian Pu
- State Key Laboratory of Resource Insects, Southwest University, Chongqing, China
| | - Shiping Liu
- State Key Laboratory of Resource Insects, Southwest University, Chongqing, China
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2
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Voß Y, Klaus S, Lichti NP, Ganter M, Guizetti J. Malaria parasite centrins can assemble by Ca2+-inducible condensation. PLoS Pathog 2023; 19:e1011899. [PMID: 38150475 PMCID: PMC10775985 DOI: 10.1371/journal.ppat.1011899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2023] [Revised: 01/09/2024] [Accepted: 12/13/2023] [Indexed: 12/29/2023] Open
Abstract
Centrins are small calcium-binding proteins that have a variety of roles and are universally associated with eukaryotic centrosomes. Rapid proliferation of the malaria-causing parasite Plasmodium falciparum in the human blood depends on a particularly divergent and acentriolar centrosome, which incorporates several essential centrins. Their precise mode of action, however, remains unclear. In this study calcium-inducible liquid-liquid phase separation is revealed as an evolutionarily conserved principle of assembly for multiple centrins from P. falciparum and other species. Furthermore, the disordered N-terminus and calcium-binding motifs are defined as essential features for reversible biomolecular condensation, and we demonstrate that certain centrins can form co-condensates. In vivo analysis using live cell STED microscopy shows liquid-like dynamics of centrosomal centrin. Additionally, implementation of an inducible protein overexpression system reveals concentration-dependent formation of extra-centrosomal centrin assemblies with condensate-like properties. The timing of foci formation and dissolution suggests that centrin assembly is regulated. This study thereby provides a new model for centrin accumulation at eukaryotic centrosomes.
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Affiliation(s)
- Yannik Voß
- Center for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
- German Center for Infection Research, partner site Heidelberg, Heidelberg, Germany
| | - Severina Klaus
- Center for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
- Department of Infectious Diseases, Virology, Heidelberg University Hospital, Heidelberg, Germany
| | - Nicolas P. Lichti
- Center for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
| | - Markus Ganter
- Center for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
| | - Julien Guizetti
- Center for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
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3
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Wenz C, Simon CS, Romão TP, Stürmer VS, Machado M, Klages N, Klemmer A, Voß Y, Ganter M, Brochet M, Guizetti J. An Sfi1-like centrin-interacting centriolar plaque protein affects nuclear microtubule homeostasis. PLoS Pathog 2023; 19:e1011325. [PMID: 37130129 PMCID: PMC10180636 DOI: 10.1371/journal.ppat.1011325] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 05/12/2023] [Accepted: 03/28/2023] [Indexed: 05/03/2023] Open
Abstract
Malaria-causing parasites achieve rapid proliferation in human blood through multiple rounds of asynchronous nuclear division followed by daughter cell formation. Nuclear divisions critically depend on the centriolar plaque, which organizes intranuclear spindle microtubules. The centriolar plaque consists of an extranuclear compartment, which is connected via a nuclear pore-like structure to a chromatin-free intranuclear compartment. Composition and function of this non-canonical centrosome remain largely elusive. Centrins, which reside in the extranuclear part, are among the very few centrosomal proteins conserved in Plasmodium falciparum. Here we identify a novel centrin-interacting centriolar plaque protein. Conditional knock down of this Sfi1-like protein (PfSlp) caused a growth delay in blood stages, which correlated with a reduced number of daughter cells. Surprisingly, intranuclear tubulin abundance was significantly increased, which raises the hypothesis that the centriolar plaque might be implicated in regulating tubulin levels. Disruption of tubulin homeostasis caused excess microtubules and aberrant mitotic spindles. Time-lapse microscopy revealed that this prevented or delayed mitotic spindle extension but did not significantly interfere with DNA replication. Our study thereby identifies a novel extranuclear centriolar plaque factor and establishes a functional link to the intranuclear compartment of this divergent eukaryotic centrosome.
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Affiliation(s)
- Christoph Wenz
- Center for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
| | | | | | | | - Marta Machado
- Center for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
- Graduate Program in Areas of Basic and Applied Biology, Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Natacha Klages
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Anja Klemmer
- Center for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
| | - Yannik Voß
- Center for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
| | - Markus Ganter
- Center for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
| | - Mathieu Brochet
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Julien Guizetti
- Center for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
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4
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Conformational Plasticity of Centrin 1 from Toxoplasma gondii in Binding to the Centrosomal Protein SFI1. Biomolecules 2022; 12:biom12081115. [PMID: 36009009 PMCID: PMC9406199 DOI: 10.3390/biom12081115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 08/09/2022] [Accepted: 08/10/2022] [Indexed: 12/01/2022] Open
Abstract
Centrins are calcium (Ca2+)-binding proteins that are involved in many cellular functions including centrosome regulation. A known cellular target of centrins is SFI1, a large centrosomal protein containing multiple repeats that represent centrin-binding motifs. Recently, a protein homologous to yeast and mammalian SFI1, denominated TgSFI1, which shares SFI1-repeat organization, was shown to colocalize at centrosomes with centrin 1 from Toxoplasma gondii (TgCEN1). However, the molecular details of the interaction between TgCEN1 and TgSFI1 remain largely unknown. Herein, combining different biophysical methods, including isothermal titration calorimetry, nuclear magnetic resonance, circular dichroism, and fluorescence spectroscopy, we determined the binding properties of TgCEN1 and its individual N- and C-terminal domains to synthetic peptides derived from distinct repeats of TgSFI1. Overall, our data indicate that the repeats in TgSFI1 constitute binding sites for TgCEN1, but the binding modes of TgCEN1 to the repeats differ appreciably in terms of binding affinity, Ca2+ sensitivity, and lobe-specific interaction. These results suggest that TgCEN1 displays remarkable conformational plasticity, allowing for the distinct repeats in TgSFI1 to possess precise modes of TgCEN1 binding and regulation during Ca2+ sensing, which appears to be crucial for the dynamic association of TgCEN1 with TgSFI1 in the centrosome architecture.
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5
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Degl’Innocenti E, Poloni TE, Medici V, Recupero L, Dell’Amico C, Vannini E, Borello U, Mazzanti CM, Onorati M, Dell’Anno MT. Centrin 2: A Novel Marker of Mature and Neoplastic Human Astrocytes. Front Cell Neurosci 2022; 16:858347. [PMID: 35573835 PMCID: PMC9100563 DOI: 10.3389/fncel.2022.858347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 03/17/2022] [Indexed: 11/13/2022] Open
Abstract
As microtubule-organizing centers (MTOCs), centrosomes play a pivotal role in cell division, neurodevelopment and neuronal maturation. Among centrosomal proteins, centrin-2 (CETN2) also contributes to DNA repair mechanisms which are fundamental to prevent genomic instability during neural stem cell pool expansion. Nevertheless, the expression profile of CETN2 in human neural stem cells and their progeny is currently unknown. To address this question, we interrogated a platform of human neuroepithelial stem (NES) cells derived from post mortem developing brain or established from pluripotent cells and demonstrated that while CETN2 retains its centrosomal location in proliferating NES cells, its expression pattern changes upon differentiation. In particular, we found that CETN2 is selectively expressed in mature astrocytes with a broad cytoplasmic distribution. We then extended our findings on human autoptic nervous tissue samples. We investigated CETN2 distribution in diverse anatomical areas along the rostro-caudal neuraxis and pointed out a peculiar topography of CETN2-labeled astrocytes in humans which was not appreciable in murine tissues, where CETN2 was mostly confined to ependymal cells. As a prototypical condition with glial overproliferation, we also explored CETN2 expression in glioblastoma multiforme (GBM), reporting a focal concentration of CETN2 in neoplastic astrocytes. This study expands CETN2 localization beyond centrosomes and reveals a unique expression pattern that makes it eligible as a novel astrocytic molecular marker, thus opening new roads to glial biology and human neural conditions.
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Affiliation(s)
- Elisa Degl’Innocenti
- Fondazione Pisana per la Scienza ONLUS, San Giuliano Terme, Italy
- Department of Translational Research and of New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | - Tino Emanuele Poloni
- Department of Neurology and Neuropathology, Golgi-Cenci Foundation and ASP Golgi-Redaelli, Abbiategrasso, Italy
| | - Valentina Medici
- Department of Neurology and Neuropathology, Golgi-Cenci Foundation and ASP Golgi-Redaelli, Abbiategrasso, Italy
| | - Luca Recupero
- Fondazione Pisana per la Scienza ONLUS, San Giuliano Terme, Italy
| | - Claudia Dell’Amico
- Unit of Cell and Developmental Biology, Department of Biology, University of Pisa, Pisa, Italy
| | | | - Ugo Borello
- Unit of Cell and Developmental Biology, Department of Biology, University of Pisa, Pisa, Italy
| | | | - Marco Onorati
- Unit of Cell and Developmental Biology, Department of Biology, University of Pisa, Pisa, Italy
| | - Maria Teresa Dell’Anno
- Fondazione Pisana per la Scienza ONLUS, San Giuliano Terme, Italy
- *Correspondence: Maria Teresa Dell’Anno,
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6
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Baluška F, Lyons S. Archaeal Origins of Eukaryotic Cell and Nucleus. Biosystems 2021; 203:104375. [PMID: 33549602 DOI: 10.1016/j.biosystems.2021.104375] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 01/29/2021] [Accepted: 01/29/2021] [Indexed: 01/12/2023]
Abstract
Symbiosis is a major evolutionary force, especially at the cellular level. Here we discuss several older and new discoveries suggesting that besides mitochondria and plastids, eukaryotic nuclei also have symbiotic origins. We propose an archaea-archaea scenario for the evolutionary origin of the eukaryotic cells. We suggest that two ancient archaea-like cells, one based on the actin cytoskeleton and another one based on the tubulin-centrin cytoskeleton, merged together to form the first nucleated eukaryotic cell. This archaeal endosymbiotic origin of eukaryotic cells and their nuclei explains several features of eukaryotic cells which are incompatible with the currently preferred autogenous scenarios of eukaryogenesis.
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Affiliation(s)
| | - Sherrie Lyons
- Union College, 130 N. College, St. - Schenectady, NY, 12305, USA.
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7
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Bornens M. Centrosome organization and functions. Curr Opin Struct Biol 2020; 66:199-206. [PMID: 33338884 DOI: 10.1016/j.sbi.2020.11.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 10/23/2020] [Accepted: 11/03/2020] [Indexed: 02/06/2023]
Abstract
The centrosome, discovered near 1875, was named by Boveri when proposing the chromosomal theory of heredity. After a long eclipse, a considerable amount of molecular data has been accumulated on the centrosome and its biogenesis in the last 30 years, summarized regularly in excellent reviews. Major questions are still at stake in 2021 however, as we lack a comprehensive view of the centrosome functions. I will first try to see how progress towards a unified view of the role of centrosomes during evolution is possible, and then review recent data on only some of the many important questions raised by this organelle.
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Affiliation(s)
- Michel Bornens
- Institut Curie, PSL University, CNRS - UMR 144, 75005 Paris, France.
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8
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Eichwald C, Ackermann M, Fraefel C. Mammalian orthoreovirus core protein μ2 reorganizes host microtubule-organizing center components. Virology 2020; 549:13-24. [PMID: 32805585 PMCID: PMC7402380 DOI: 10.1016/j.virol.2020.07.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 07/02/2020] [Accepted: 07/08/2020] [Indexed: 10/26/2022]
Abstract
Filamentous mammalian orthoreovirus (MRV) viral factories (VFs) are membrane-less cytosolic inclusions in which virus transcription, replication of dsRNA genome segments, and packaging of virus progeny into newly synthesized virus cores take place. In infected cells, the MRV μ2 protein forms punctae in the enlarged region of the filamentous VFs that are co-localized with γ-tubulin and resistant to nocodazole treatment, and permitted microtubule (MT)-extension, features common to MT-organizing centers (MTOCs). Using a previously established reconstituted VF model, we addressed the functions of MT-components and MTOCs concerning their roles in the formation of filamentous VFs. Indeed, the MTOC markers γ-tubulin and centrin were redistributed within the VF-like structures (VFLS) in a μ2-dependent manner. Moreover, the MT-nucleation centers significantly increased in numbers, and γ-tubulin was pulled-down in a binding assay when co-expressed with histidine-tagged-μ2 and μNS. Thus, μ2, by interaction with γ-tubulin, can modulate MTOCs localization and function according to viral needs.
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Affiliation(s)
- Catherine Eichwald
- Institute of Virology, University of Zurich, Winterthurerstrasse 266a, 8057 Zurich, Switzerland.
| | - Mathias Ackermann
- Institute of Virology, University of Zurich, Winterthurerstrasse 266a, 8057 Zurich, Switzerland.
| | - Cornel Fraefel
- Institute of Virology, University of Zurich, Winterthurerstrasse 266a, 8057 Zurich, Switzerland.
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9
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Leung JM, Liu J, Wetzel LA, Hu K. Centrin2 from the human parasite Toxoplasma gondii is required for its invasion and intracellular replication. J Cell Sci 2019; 132:jcs.228791. [PMID: 31182647 DOI: 10.1242/jcs.228791] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 06/03/2019] [Indexed: 12/24/2022] Open
Abstract
Centrins are EF-hand containing proteins ubiquitously found in eukaryotes and are key components of centrioles/basal bodies as well as certain contractile fibers. We previously identified three centrins in the human parasite Toxoplasma gondii, all of which localized to the centrioles. However, one of them, T. gondii (Tg) Centrin2 (CEN2), is also targeted to structures at the apical and basal ends of the parasite, as well as to annuli at the base of the apical cap of the membrane cortex. The role(s) that CEN2 play in these locations were unknown. Here, we report the functional characterization of CEN2 using a conditional knockdown method that combines transcriptional and protein stability control. The knockdown resulted in an ordered loss of CEN2 from its four compartments, due to differences in incorporation kinetics and structural inheritance over successive generations. This was correlated with a major invasion deficiency at early stages of CEN2 knockdown, and replication defects at later stages. These results indicate that CEN2 is incorporated into multiple cytoskeletal structures to serve distinct functions that are required for parasite survival.
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Affiliation(s)
| | - Jun Liu
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - Laura A Wetzel
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - Ke Hu
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
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10
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Ying G, Frederick JM, Baehr W. Deletion of both centrin 2 (CETN2) and CETN3 destabilizes the distal connecting cilium of mouse photoreceptors. J Biol Chem 2019; 294:3957-3973. [PMID: 30647131 DOI: 10.1074/jbc.ra118.006371] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 01/09/2019] [Indexed: 02/03/2023] Open
Abstract
Centrins (CETN1-4) are ubiquitous and conserved EF-hand-family Ca2+-binding proteins associated with the centrosome, basal body, and transition zone. Deletion of CETN1 or CETN2 in mice causes male infertility or dysosmia, respectively, without affecting photoreceptor function. However, it remains unclear to what extent centrins are redundant with each other in photoreceptors. Here, to explore centrin redundancy, we generated Cetn3 GT/GT single-knockout and Cetn2 -/-;Cetn3 GT/GT double-knockout mice. Whereas the Cetn3 deletion alone did not affect photoreceptor function, simultaneous ablation of Cetn2 and Cetn3 resulted in attenuated scotopic and photopic electroretinography (ERG) responses in mice at 3 months of age, with nearly complete retina degeneration at 1 year. Removal of CETN2 and CETN3 activity from the lumen of the connecting cilium (CC) destabilized the photoreceptor axoneme and reduced the CC length as early as postnatal day 22 (P22). In Cetn2 -/-;Cetn3 GT/GT double-knockout mice, spermatogenesis-associated 7 (SPATA7), a key organizer of the photoreceptor-specific distal CC, was depleted gradually, and CETN1 was condensed to the mid-segment of the CC. Ultrastructural analysis revealed that in this double knockout, the axoneme of the CC expanded radially at the distal end, with vertically misaligned outer segment discs and membrane whorls. These observations suggest that CETN2 and CETN3 cooperate in stabilizing the CC/axoneme structure.
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Affiliation(s)
- Guoxin Ying
- From the Department of Ophthalmology, University of Utah Health Science Center, Salt Lake City, Utah 84132,
| | - Jeanne M Frederick
- From the Department of Ophthalmology, University of Utah Health Science Center, Salt Lake City, Utah 84132
| | - Wolfgang Baehr
- From the Department of Ophthalmology, University of Utah Health Science Center, Salt Lake City, Utah 84132, .,the Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, Utah 84112, and.,the Department of Biology, University of Utah, Salt Lake City, Utah 84132
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11
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Baluška F, Lyons S. Energide-cell body as smallest unit of eukaryotic life. ANNALS OF BOTANY 2018; 122:741-745. [PMID: 29474513 PMCID: PMC6215040 DOI: 10.1093/aob/mcy022] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 02/01/2018] [Indexed: 06/08/2023]
Abstract
Background The evolutionary origin of the eukaryotic nucleus is obscure and controversial. Currently preferred are autogenic concepts; ideas of a symbiotic origin are mostly discarded and forgotten. Here we briefly discuss these issues and propose a new version of the symbiotic and archaeal origin of the eukaryotic nucleus. Scope and Conclusions The nucleus of eukaryotic cells forms via its perinuclear microtubules, the primary eukaryotic unit known also as the Energide-cell body. As for all other endosymbiotic organelles, new Energides are generated only from other Energides. While the Energide cannot be generated de novo, it can use its secretory apparatus to generate de novo the cell periphery apparatus. We suggest that Virchow's tenet Omnis cellula e cellula should be updated as Omnis Energide e Energide to reflect the status of the Energide as the primary unit of the eukaryotic cell, and life. In addition, the plasma membrane provides feedback to the Energide and renders it protection via the plasma membrane-derived endosomal network. New discoveries suggest archaeal origins of both the Energide and its host cell.
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12
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Simerly C, Manil-Ségalen M, Castro C, Hartnett C, Kong D, Verlhac MH, Loncarek J, Schatten G. Separation and Loss of Centrioles From Primordidal Germ Cells To Mature Oocytes In The Mouse. Sci Rep 2018; 8:12791. [PMID: 30143724 PMCID: PMC6109097 DOI: 10.1038/s41598-018-31222-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 08/09/2018] [Indexed: 12/15/2022] Open
Abstract
Oocytes, including from mammals, lack centrioles, but neither the mechanism by which mature eggs lose their centrioles nor the exact stage at which centrioles are destroyed during oogenesis is known. To answer questions raised by centriole disappearance during oogenesis, using a transgenic mouse expressing GFP-centrin-2 (GFP CETN2), we traced their presence from e11.5 primordial germ cells (PGCs) through oogenesis and their ultimate dissolution in mature oocytes. We show tightly coupled CETN2 doublets in PGCs, oogonia, and pre-pubertal oocytes. Beginning with follicular recruitment of incompetent germinal vesicle (GV) oocytes, through full oocyte maturation, the CETN2 doublets separate within the pericentriolar material (PCM) and a rise in single CETN2 pairs is identified, mostly at meiotic metaphase-I and -II spindle poles. Partial CETN2 foci dissolution occurs even as other centriole markers, like Cep135, a protein necessary for centriole duplication, are maintained at the PCM. Furthermore, live imaging demonstrates that the link between the two centrioles breaks as meiosis resumes and that centriole association with the PCM is progressively lost. Microtubule inhibition shows that centriole dissolution is uncoupled from microtubule dynamics. Thus, centriole doublets, present in early G2-arrested meiotic prophase oocytes, begin partial reduction during follicular recruitment and meiotic resumption, later than previously thought.
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Affiliation(s)
- Calvin Simerly
- Departments of Cell Biology; Obstetrics, Gynecology and Reproductive Sciences; and Bioengineering, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15213, USA
| | - Marion Manil-Ségalen
- Center for Interdisciplinary Research in Biology (CIRB) Collège de France, CNRS, INSERM, PSL Research University, Equipe labellisée FRM, Paris, France
| | - Carlos Castro
- Departments of Cell Biology; Obstetrics, Gynecology and Reproductive Sciences; and Bioengineering, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15213, USA
| | - Carrie Hartnett
- Departments of Cell Biology; Obstetrics, Gynecology and Reproductive Sciences; and Bioengineering, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15213, USA
| | - Dong Kong
- Laboratory of Protein Dynamics and Signaling, National Institutes of Health/Center for Cancer Research/National Cancer Institute-Frederick, Frederick, MD, 21702, USA
| | - Marie-Hélène Verlhac
- Center for Interdisciplinary Research in Biology (CIRB) Collège de France, CNRS, INSERM, PSL Research University, Equipe labellisée FRM, Paris, France
| | - Jadranka Loncarek
- Laboratory of Protein Dynamics and Signaling, National Institutes of Health/Center for Cancer Research/National Cancer Institute-Frederick, Frederick, MD, 21702, USA
| | - Gerald Schatten
- Departments of Cell Biology; Obstetrics, Gynecology and Reproductive Sciences; and Bioengineering, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15213, USA.
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13
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Abstract
Pre-mRNA processing protein 40 (Prp40) is a nuclear protein that has a role in pre-mRNA splicing. Prp40 possesses two leucine-rich nuclear export signals, but little is known about the function of Prp40 in the export process. Another protein that has a role in protein export is centrin, a member of the EF-hand superfamily of Ca2+-binding proteins. Prp40 was found to be a centrin target by yeast-two-hybrid screening using both Homo sapiens centrin 2 (Hscen2) and Chlamydomonas reinhardtii centrin (Crcen). We identified a centrin-binding site within H. sapiens Prp40 homolog A (HsPrp40A), which contains a hydrophobic triad W1L4L8 that is known to be important in the interaction with centrin. This centrin-binding site is highly conserved within the first nuclear export signal consensus sequence identified in Saccharomyces cerevisiae Prp40. Here, we examine the interaction of HsPrp40A peptide (HsPrp40Ap) with both Hscen2 and Crcen by isothermal titration calorimetry. We employed the thermodynamic parameterization to estimate the polar and apolar surface area of the interface. In addition, we have defined the molecular mechanism of thermally induced unfolding and dissociation of the Crcen-HsPrp40Ap complex using two-dimensional infrared correlation spectroscopy. These complementary techniques showed for the first time, to our knowledge, that HsPrp40Ap interacts with centrin in vitro, supporting a coupled functional role for these proteins in pre-mRNA splicing.
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14
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Morlon-Guyot J, Francia ME, Dubremetz JF, Daher W. Towards a molecular architecture of the centrosome in Toxoplasma gondii. Cytoskeleton (Hoboken) 2017; 74:55-71. [PMID: 28026138 DOI: 10.1002/cm.21353] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 12/14/2016] [Accepted: 12/15/2016] [Indexed: 12/21/2022]
Abstract
Toxoplasma gondii is the causative agent of toxoplasmosis. The pathogenicity of this unicellular parasite is tightly linked to its ability to efficiently proliferate within its host. Tachyzoites, the fast dividing form of the parasite, divide by endodyogeny. This process involves a single round of DNA replication, closed nuclear mitosis, and assembly of two daughter cells within a mother. The successful completion of endodyogeny relies on the temporal and spatial coordination of a plethora of simultaneous events. It has been shown that the Toxoplasma centrosome serves as signaling hub which nucleates spindle microtubules during mitosis and organizes the scaffolding of daughter cells components during cytokinesis. In addition, the centrosome is essential for inheriting both the apicoplast (a chloroplast-like organelle) and the Golgi apparatus. A growing body of evidence supports the notion that the T. gondii centrosome diverges in protein composition, structure and organization from its counterparts in higher eukaryotes making it an attractive source of potentially druggable targets. Here, we summarize the current knowledge on T. gondii centrosomal proteins and extend the putative centrosomal protein repertoire by in silico identification of mammalian centrosomal protein orthologs. We propose a working model for the organization and architecture of the centrosome in Toxoplasma parasites. Experimental validation of our proposed model will uncover how each predicted protein translates into the biology of centrosome, cytokinesis, karyokinesis, and organelle inheritance in Toxoplasma parasites.
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Affiliation(s)
- Juliette Morlon-Guyot
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR5235 CNRS, Université Montpellier, Montpellier, France
| | - Maria E Francia
- Molecular Biology Unit, Institut Pasteur de Montevideo, Mataojo 2020, Montevideo, 11400, Uruguay
| | - Jean-François Dubremetz
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR5235 CNRS, Université Montpellier, Montpellier, France
| | - Wassim Daher
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR5235 CNRS, Université Montpellier, Montpellier, France
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15
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Abstract
For over a century, the abnormal movement or number of centrosomes has been linked with errors of chromosomes distribution in mitosis. While not essential for the formation of the mitotic spindle, the presence and location of centrosomes has a major influence on the manner in which microtubules interact with the kinetochores of replicated sister chromatids and the accuracy with which they migrate to resulting daughter cells. A complex network has evolved to ensure that cells contain the proper number of centrosomes and that their location is optimal for effective attachment of emanating spindle fibers with the kinetochores. The components of this network are regulated through a series of post-translational modifications, including ubiquitin and ubiquitin-like modifiers, which coordinate the timing and strength of signaling events key to the centrosome cycle. In this review, we examine the role of the ubiquitin system in the events relating to centriole duplication and centrosome separation, and discuss how the disruption of these functions impacts chromosome segregation.
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16
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Viguès B, Colombet J, Damaj R. Differential localization and functional specialization of centrin analogs in the parasitic ciliate Trichodina pediculus. PROTOPLASMA 2016; 253:1385-1388. [PMID: 26340903 DOI: 10.1007/s00709-015-0878-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 08/18/2015] [Indexed: 06/05/2023]
Abstract
Trichodinids are ciliated protozoans that reversibly attach to the tegument of marine and freshwater host-organisms via an adhesive disc. In this study, we have used permeabilized cell models of Trichodina pediculus to examine the distribution of centrins, a Ca(2+)-binding protein associated with centrioles and/or contractile filamentous structures in a large number of protists. The previous finding that filamentous material of the adhesive disc comprised a 23-kDa centrin analog suggested that this protein might be a disc-specific isoform. This possibility was explored through immunolabeling methods using two distinct antibodies, anti-ecto-endoplasmic boundary (EEB) and anti-Hscen2 previously shown to react respectively with centrin-based filament networks and with centrioles. Immunofluorescence microscopy showed that anti-EEB reacts with filamentous material of the disc but not with basal bodies. Conversely, anti-Hscen2 cross-reacted with basal bodies but failed to label any type of structure occurring in the disc area. More detailed data on localization of this protein was obtained by immunoelectron microscopy showing gold particles deposits in the lumen of basal bodies. The different patterns revealed by this immunochemical approach suggest that the two protein antigens concerned by this study are distinct centrin isoforms that presumably perform organelle-specific function in the ciliate T. pediculus.
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Affiliation(s)
- Bernard Viguès
- UMR CNRS 6023, Laboratoire Microorganismes, Génome et Environnement, Université Blaise Pascal Clermont-Ferrand II, 24 Avenue des Landais, BP 80026, 63 171, Aubière Cedex, France.
| | - Jonathan Colombet
- UMR CNRS 6023, Laboratoire Microorganismes, Génome et Environnement, Université Blaise Pascal Clermont-Ferrand II, 24 Avenue des Landais, BP 80026, 63 171, Aubière Cedex, France
| | - Raghida Damaj
- UMR CNRS 6023, Laboratoire Microorganismes, Génome et Environnement, Université Blaise Pascal Clermont-Ferrand II, 24 Avenue des Landais, BP 80026, 63 171, Aubière Cedex, France
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17
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Pastrana-Rios B, Del Valle Sosa L, Santiago J. Trifluoroacetic acid as excipient destabilizes melittin causing the selective aggregation of melittin within the centrin-melittin-trifluoroacetic acid complex. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2015; 2:041711. [PMID: 26798810 PMCID: PMC4711628 DOI: 10.1063/1.4921219] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/22/2015] [Accepted: 04/28/2015] [Indexed: 06/05/2023]
Abstract
Trifluoroacetic acid (TFA) may be the cause of the bottleneck in high resolution structure determination for protein-peptide complexes. Fragment based drug design often involves the use of synthetic peptides which contain TFA (excipient). Our goal was to explore the effects of this excipient on a model complex: centrin-melittin-TFA. We performed Fourier transform infrared, two-dimensional infrared correlation spectroscopies and spectral simulations to analyze the amide I'/I'* band for the components and the ternary complex. Melittin (MLT) was observed to have increased helicity upon its interaction with centrin, followed by the thermally induced aggregation of MLT within the ternary complex in the TFA presence.
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Affiliation(s)
| | - Liliana Del Valle Sosa
- Department of Chemistry, University of Puerto Rico , Mayagüez Campus, Call Box 9019, Mayagüez, Puerto Rico 00681, USA
| | - Jorge Santiago
- Department of Chemistry, University of Puerto Rico , Mayagüez Campus, Call Box 9019, Mayagüez, Puerto Rico 00681, USA
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18
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Cross FR, Umen JG. The Chlamydomonas cell cycle. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2015; 82:370-392. [PMID: 25690512 PMCID: PMC4409525 DOI: 10.1111/tpj.12795] [Citation(s) in RCA: 119] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 02/03/2015] [Accepted: 02/04/2015] [Indexed: 05/18/2023]
Abstract
The position of Chlamydomonas within the eukaryotic phylogeny makes it a unique model in at least two important ways: as a representative of the critically important, early-diverging lineage leading to plants; and as a microbe retaining important features of the last eukaryotic common ancestor (LECA) that has been lost in the highly studied yeast lineages. Its cell biology has been studied for many decades and it has well-developed experimental genetic tools, both classical (Mendelian) and molecular. Unlike land plants, it is a haploid with very few gene duplicates, making it ideal for loss-of-function genetic studies. The Chlamydomonas cell cycle has a striking temporal and functional separation between cell growth and rapid cell division, probably connected to the interplay between diurnal cycles that drive photosynthetic cell growth and the cell division cycle; it also exhibits a highly choreographed interaction between the cell cycle and its centriole-basal body-flagellar cycle. Here, we review the current status of studies of the Chlamydomonas cell cycle. We begin with an overview of cell-cycle control in the well-studied yeast and animal systems, which has yielded a canonical, well-supported model. We discuss briefly what is known about similarities and differences in plant cell-cycle control, compared with this model. We next review the cytology and cell biology of the multiple-fission cell cycle of Chlamydomonas. Lastly, we review recent genetic approaches and insights into Chlamydomonas cell-cycle regulation that have been enabled by a new generation of genomics-based tools.
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Affiliation(s)
| | - James G Umen
- Donald Danforth Plant Science Center, St. Louis, MO, 63132, USA
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19
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Abstract
The centrosome was discovered in the late 19th century when mitosis was first described. Long recognized as a key organelle of the spindle pole, its core component, the centriole, was realized more than 50 or so years later also to comprise the basal body of the cilium. Here, we chart the more recent acquisition of a molecular understanding of centrosome structure and function. The strategies for gaining such knowledge were quickly developed in the yeasts to decipher the structure and function of their distinctive spindle pole bodies. Only within the past decade have studies with model eukaryotes and cultured cells brought a similar degree of sophistication to our understanding of the centrosome duplication cycle and the multiple roles of this organelle and its component parts in cell division and signaling. Now as we begin to understand these functions in the context of development, the way is being opened up for studies of the roles of centrosomes in human disease.
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Affiliation(s)
- Jingyan Fu
- Cancer Research UK Cell Cycle Genetics Group, Department of Genetics, University of Cambridge, Cambridge CB2 3EH, United Kingdom
| | - Iain M Hagan
- Cancer Research UK Manchester Institute, University of Manchester, Withington, Manchester M20 4BX, United Kingdom
| | - David M Glover
- Cancer Research UK Cell Cycle Genetics Group, Department of Genetics, University of Cambridge, Cambridge CB2 3EH, United Kingdom
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20
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Vicente JJ, Cande WZ. Mad2, Bub3, and Mps1 regulate chromosome segregation and mitotic synchrony in Giardia intestinalis, a binucleate protist lacking an anaphase-promoting complex. Mol Biol Cell 2014; 25:2774-87. [PMID: 25057014 PMCID: PMC4161512 DOI: 10.1091/mbc.e14-05-0975] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The binucleate pathogen Giardia intestinalis is a highly divergent eukaryote with a semiopen mitosis, lacking an anaphase-promoting complex/cyclosome (APC/C) and many of the mitotic checkpoint complex (MCC) proteins. However, Giardia has some MCC components (Bub3, Mad2, and Mps1) and proteins from the cohesin system (Smc1 and Smc3). Mad2 localizes to the cytoplasm, but Bub3 and Mps1 are either located on chromosomes or in the cytoplasm, depending on the cell cycle stage. Depletion of Bub3, Mad2, or Mps1 resulted in a lowered mitotic index, errors in chromosome segregation (including lagging chromosomes), and abnormalities in spindle morphology. During interphase, MCC knockdown cells have an abnormal number of nuclei, either one nucleus usually on the left-hand side of the cell or two nuclei with one mislocalized. These results suggest that the minimal set of MCC proteins in Giardia play a major role in regulating many aspects of mitosis, including chromosome segregation, coordination of mitosis between the two nuclei, and subsequent nuclear positioning. The critical importance of MCC proteins in an organism that lacks their canonical target, the APC/C, suggests a broader role for these proteins and hints at new pathways to be discovered.
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Affiliation(s)
- Juan-Jesus Vicente
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - W Zacheus Cande
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
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21
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Lee IJ, Wang N, Hu W, Schott K, Bähler J, Giddings TH, Pringle JR, Du LL, Wu JQ. Regulation of spindle pole body assembly and cytokinesis by the centrin-binding protein Sfi1 in fission yeast. Mol Biol Cell 2014; 25:2735-49. [PMID: 25031431 PMCID: PMC4161509 DOI: 10.1091/mbc.e13-11-0699] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
A previous model suggested doubling of Sfi1 as the first step of SPB assembly. Here it is shown that Sfi1 is gradually recruited to SPBs throughout the cell cycle. Conserved tryptophans in Sfi1 are required for its equal partitioning during mitosis, and unequal partitioning of Sfi1 underlies SPB assembly and mitotic defects in the next cell cycle. Centrosomes play critical roles in the cell division cycle and ciliogenesis. Sfi1 is a centrin-binding protein conserved from yeast to humans. Budding yeast Sfi1 is essential for the initiation of spindle pole body (SPB; yeast centrosome) duplication. However, the recruitment and partitioning of Sfi1 to centrosomal structures have never been fully investigated in any organism, and the presumed importance of the conserved tryptophans in the internal repeats of Sfi1 remains untested. Here we report that in fission yeast, instead of doubling abruptly at the initiation of SPB duplication and remaining at a constant level thereafter, Sfi1 is gradually recruited to SPBs throughout the cell cycle. Like an sfi1Δ mutant, a Trp-to-Arg mutant (sfi1-M46) forms monopolar spindles and exhibits mitosis and cytokinesis defects. Sfi1-M46 protein associates preferentially with one of the two daughter SPBs during mitosis, resulting in a failure of new SPB assembly in the SPB receiving insufficient Sfi1. Although all five conserved tryptophans tested are involved in Sfi1 partitioning, the importance of the individual repeats in Sfi1 differs. In summary, our results reveal a link between the conserved tryptophans and Sfi1 partitioning and suggest a revision of the model for SPB assembly.
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Affiliation(s)
- I-Ju Lee
- Graduate Program of Molecular, Cellular, and Developmental Biology, The Ohio State University, Columbus, OH 43210 Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210
| | - Ning Wang
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210
| | - Wen Hu
- National Institute of Biological Sciences, Beijing 102206, China
| | - Kersey Schott
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210
| | - Jürg Bähler
- Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, United Kingdom
| | - Thomas H Giddings
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado-Boulder, Boulder, CO 80309
| | - John R Pringle
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305
| | - Li-Lin Du
- National Institute of Biological Sciences, Beijing 102206, China
| | - Jian-Qiu Wu
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210 Department of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, OH 43210
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22
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Centrin 2 is required for mouse olfactory ciliary trafficking and development of ependymal cilia planar polarity. J Neurosci 2014; 34:6377-88. [PMID: 24790208 DOI: 10.1523/jneurosci.0067-14.2014] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Centrins are ancient calmodulin-related Ca(2+)-binding proteins associated with basal bodies. In lower eukaryotes, Centrin2 (CETN2) is required for basal body replication and positioning, although its function in mammals is undefined. We generated a germline CETN2 knock-out (KO) mouse presenting with syndromic ciliopathy including dysosmia and hydrocephalus. Absence of CETN2 leads to olfactory cilia loss, impaired ciliary trafficking of olfactory signaling proteins, adenylate cyclase III (ACIII), and cyclic nucleotide-gated (CNG) channel, as well as disrupted basal body apical migration in postnatal olfactory sensory neurons (OSNs). In mutant OSNs, cilia base-anchoring of intraflagellar transport components IFT88, the kinesin-II subunit KIF3A, and cytoplasmic dynein 2 appeared compromised. Although the densities of mutant ependymal and respiratory cilia were largely normal, the planar polarity of mutant ependymal cilia was disrupted, resulting in uncoordinated flow of CSF. Transgenic expression of GFP-CETN2 rescued the Cetn2-deficiency phenotype. These results indicate that mammalian basal body replication and ciliogenesis occur independently of CETN2; however, mouse CETN2 regulates protein trafficking of olfactory cilia and participates in specifying planar polarity of ependymal cilia.
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23
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Cunningham CN, Schmidt CA, Schramm NJ, Gaylord MR, Resendes KK. Human TREX2 components PCID2 and centrin 2, but not ENY2, have distinct functions in protein export and co-localize to the centrosome. Exp Cell Res 2013; 320:209-18. [PMID: 24291146 DOI: 10.1016/j.yexcr.2013.11.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Revised: 11/15/2013] [Accepted: 11/19/2013] [Indexed: 11/15/2022]
Abstract
TREX-2 is a five protein complex, conserved from yeast to humans, involved in linking mRNA transcription and export. The centrin 2 subunit of TREX-2 is also a component of the centrosome and is additionally involved in a distinctly different process of nuclear protein export. While centrin 2 is a known multifunctional protein, the roles of other human TREX-2 complex proteins other than mRNA export are not known. In this study, we found that human TREX-2 member PCID2 but not ENY2 is involved in some of the same cellular processes as those of centrin 2 apart from the classical TREX-2 function. PCID2 is present at the centrosome in a subset of HeLa cells and this localization is centrin 2 dependent. Furthermore, the presence of PCID2 at the centrosome is prevalent throughout the cell cycle as determined by co-staining with cyclins E, A and B. PCID2 but not ENY2 is also involved in protein export. Surprisingly, siRNA knockdown of PCID2 delayed the rate of nuclear protein export, a mechanism distinct from the effects of centrin 2, which when knocked down inhibits export. Finally we showed that co-depletion of centrin 2 and PCID2 leads to blocking rather than delaying nuclear protein export, indicating the dominance of the centrin 2 phenotype. Together these results represent the first discovery of specific novel functions for PCID2 other than mRNA export and suggest that components of the TREX-2 complex serve alternative shared roles in the regulation of nuclear transport and cell cycle progression.
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Affiliation(s)
- Corey N Cunningham
- Westminster College, Department of Biology, 319 South Market Street, New Wilmington, PA 16172, USA
| | - Casey A Schmidt
- Westminster College, Department of Biology, 319 South Market Street, New Wilmington, PA 16172, USA
| | - Nathaniel J Schramm
- Westminster College, Department of Biology, 319 South Market Street, New Wilmington, PA 16172, USA
| | - Michelle R Gaylord
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California - San Diego, 9500 Gilman Drive, #0347, La Jolla, CA 92093-0347, USA
| | - Karen K Resendes
- Westminster College, Department of Biology, 319 South Market Street, New Wilmington, PA 16172, USA.
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24
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Chen CT, Gubbels MJ. The Toxoplasma gondii centrosome is the platform for internal daughter budding as revealed by a Nek1 kinase mutant. J Cell Sci 2013; 126:3344-55. [PMID: 23729737 DOI: 10.1242/jcs.123364] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The pathology and severity of toxoplasmosis results from the rapid replication cycle of the apicomplexan parasite Toxoplasma gondii. The tachyzoites divide asexually through endodyogeny, wherein two daughter cells bud inside the mother cell. Before mitosis is completed, the daughter buds form around the duplicated centrosomes and subsequently elongate to serve as the scaffold for organellogenesis and organelle partitioning. The molecular control mechanism of this process is poorly understood. Here, we characterized a T. gondii NIMA-related kinase (Nek) ortholog that was identified in a chemical mutagenesis screen. A temperature-sensitive mutant, V-A15, possesses a Cys316Arg mutation in TgNek1 (a novel mutant allele in Neks), which is responsible for growth defects at the restrictive temperature. Phenotypic analysis of V-A15 indicated that TgNek1 is essential for centrosome splitting, proper formation of daughter cells and faithful segregation of genetic material. In vitro kinase assays showed that the mutation abolishes the kinase activity of TgNek1. TgNek1 is recruited to the centrosome prior to its duplication and localizes on the duplicated centrosomes facing the spindle poles in a cell-cycle-dependent manner. Mutational analysis of the activation loop suggests that localization and activity are spatio-temporally regulated by differential phosphorylation. Collectively, our results identified a novel temperature-sensitive allele for a Nek kinase and highlight its essential function in centrosome splitting in Toxoplasma. Moreover, these results conclusively show for the first time that Toxoplasma bud assembly is facilitated by the centrosome because defective centrosome splitting results in single daughter cell budding.
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Affiliation(s)
- Chun-Ti Chen
- Department of Biology, Boston College, Chestnut Hill, MA 02467, USA
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25
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Pastrana-Ríos B, Reyes M, De Orbeta J, Meza V, Narváez D, Gómez AM, Rodríguez Nassif A, Almodovar R, Díaz Casas A, Robles J, Ortiz AM, Irizarry L, Campbell M, Colón M. Relative stability of human centrins and its relationship to calcium binding. Biochemistry 2013; 52:1236-48. [PMID: 23346931 PMCID: PMC3597381 DOI: 10.1021/bi301417z] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Revised: 01/20/2013] [Indexed: 11/28/2022]
Abstract
Centrins are calcium binding proteins that belong to the EF-hand superfamily with diverse biological functions. Herein we present the first systematic study that establishes the relative stability of related centrins via complementary biophysical techniques. Our results define the stepwise molecular behavior of human centrins by two-dimensional infrared (2D IR) correlation spectroscopy, the change in heat capacity and enthalpy of denaturation by differential scanning calorimetry, and the relative stability of the helical regions of centrins by circular dichroism. More importantly, 2D IR correlation spectroscopy provides unique information about the similarities and differences in dynamics between these related proteins. The thermally induced molecular behavior of human centrins can be used to predict biological target interactions that have a relative dependence on calcium affinity. This information is essential for understanding why certain isoforms may be used to rescue a phenotype and therefore also for explaining the different functions these proteins may have in vivo. Furthermore, this comparative approach can be applied to the study of recombinant therapeutic protein candidates for the treatment of disease states.
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Affiliation(s)
- Belinda Pastrana-Ríos
- Protein Research Center, University of Puerto Rico, Mayagüez Campus, Mayagüez, Puerto Rico 00681-9019, USA.
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26
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Delaval B, Covassin L, Lawson ND, Doxsey S. Centrin depletion causes cyst formation and other ciliopathy-related phenotypes in zebrafish. Cell Cycle 2011; 10:3964-72. [PMID: 22142866 DOI: 10.4161/cc.10.22.18150] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Most bona fide centrosome proteins including centrins, small calcium-binding proteins, participate in spindle function during mitosis and play a role in cilia assembly in non-cycling cells. Although the basic cellular functions of centrins have been studied in lower eukaryotes and vertebrate cells in culture, phenotypes associated with centrin depletion in vertebrates in vivo has not been directly addressed. To test this, we depleted centrin2 in zebrafish and found that it leads to ciliopathy phenotypes including enlarged pronephric tubules and pronephric cysts. Consistent with the ciliopathy phenotypes, cilia defects were observed in differentiated epithelial cells of ciliated organs such as the olfactory bulb and pronephric duct. The organ phenotypes were also accompanied by cell cycle deregulation namely mitotic delay resulting from mitotic defects. Overall, this work demonstrates that centrin2 depletion causes cilia-related disorders in zebrafish. Moreover, given the presence of both cilia and mitotic defects in the affected organs, it suggests that cilia disorders may arise from a combination of these defects.
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Affiliation(s)
- Benedicte Delaval
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, USA
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27
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Sosa LDV, Alfaro E, Santiago J, Narváez D, Rosado MC, Rodríguez A, Gómez AM, Schreiter ER, Pastrana-Ríos B. The structure, molecular dynamics, and energetics of centrin-melittin complex. Proteins 2011; 79:3132-43. [PMID: 21989934 DOI: 10.1002/prot.23142] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2011] [Revised: 06/25/2011] [Accepted: 07/08/2011] [Indexed: 11/09/2022]
Abstract
Centrin is a calcium binding protein (CaBP) belonging to the EF-hand superfamily. As with other proteins within this family, centrin is a calcium sensor with multiple biological target proteins. We chose to study Chlamydomonas reinhardtii centrin (Crcen) and its interaction with melittin (MLT) as a model for CaBP complexes due to its amphipathic properties. Our goal was to determine the molecular interactions that lead to centrin-MLT complex formation, their relative stability, and the conformational changes associated with the interaction, when compared to the single components. For this, we determined the thermodynamic parameters that define Crcen-MLT complex formation. Two-dimensional infrared (2D IR) correlation spectroscopy were used to study the amide I', I'*, and side chain bands for (13)C-Crcen, MLT, and the (13)C-Crcen-MLT complex. This approach resulted in the determination of MLT's increased helicity, while centrin was stabilized within the complex. Herein we provide the first complete molecular description of centrin-MLT complex formation and the dissociation process. Also, discussed is the first structure of a CaBP-MLT complex by X-ray crystallography, which shows that MLT has a different binding orientation than previously characterized centrin-bound peptides. Finally, all of the experimental results presented herein are consistent with centrin maintaining an extended conformation while interacting with MLT. The molecular implications of these results are: (1) the recognition of hydrophobic contacts as requirements for initial binding, (2) minimum electrostatic interactions within the C-terminal end of the peptide, and (3) van der Waals interactions within MLTs N-terminal end are required for complex formation.
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28
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Wolniak SM, van der Weele CM, Deeb F, Boothby T, Klink VP. Extremes in rapid cellular morphogenesis: post-transcriptional regulation of spermatogenesis in Marsilea vestita. PROTOPLASMA 2011; 248:457-73. [PMID: 21487804 DOI: 10.1007/s00709-011-0276-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Accepted: 03/30/2011] [Indexed: 05/07/2023]
Abstract
The endosporic male gametophyte of the water fern, Marsilea vestita, provides a unique opportunity to study the mechanisms that control cell fate determination during a burst of rapid development. In this review, we show how the spatial and temporal control of development in this simple gametophyte involves several distinct modes of RNA processing that allow the translation of specific mRNAs at distinct stages during gametogenesis. During the early part of development, nine successive cell division cycles occur in precise planes within a closed volume to produce seven sterile cells and 32 spermatids. There is no cell movement in the gametophyte; so, cell position and size within the spore wall define cell fate. After the division cycles have been completed, the spermatids become sites for the de novo formation of basal bodies, for the assembly of a complex cytoskeleton, for nuclear and cell elongation, and for ciliogenesis. In contrast, the adjacent sterile cells exhibit none of these changes. The spermatids differentiate into multiciliated, corkscrew-shaped gametes that resemble no other cells in the entire plant. Development is controlled post-transcriptionally. The transcripts stored in the microspore are released (unmasked) in the gametophyte at different times during development. At the start of these studies, we identified several key mRNAs that undergo translation at specific stages of gametophyte development. We developed RNA silencing protocols that enabled us to block the translation of these proteins and thereby establish their necessity and sufficiency for the completion of specific stages of gametogenesis. In addition, RNAi enabled us to identify additional proteins that are essential for other phases of development. Since the distributions of mRNAs and the proteins they encode are not identical in the gametophyte, transcript processing is apparently important in allowing translation to occur under strict temporal and spatial control. Transcript polyadenylation occurs in the spermatogenous cells in ways that match the translation of specific mRNAs. We have found that the exon junction complex plays key roles in transcript regulation and modifications that underlie cell specification in the gametophyte. We have recently become interested in the mechanisms that control the unmasking of the stored transcripts and have linked the synthesis and redistribution of spermidine in the gametophyte to the control of mRNA release from storage during early development and later to basal body formation, cytoskeletal assembly, and nuclear and cell elongation in the differentiating spermatids.
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Affiliation(s)
- Stephen M Wolniak
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA.
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CDC25B associates with a centrin 2-containing complex and is involved in maintaining centrosome integrity. Biol Cell 2011; 103:55-68. [PMID: 21091437 PMCID: PMC3025493 DOI: 10.1042/bc20100111] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Background information. CDC25 (cell division cycle 25) phosphatases function as activators of CDK (cyclin-dependent kinase)–cyclin complexes to regulate progression through the CDC. We have recently identified a pool of CDC25B at the centrosome of interphase cells that plays a role in regulating centrosome numbers. Results. In the present study, we demonstrate that CDC25B forms a close association with Ctn (centrin) proteins at the centrosome. This interaction involves both N- and C-terminal regions of CDC25B and requires CDC25B binding to its CDK–cyclin substrates. However, the interaction is not dependent on the enzyme activity of CDC25B. Although CDC25B appears to bind indirectly to Ctn2, this association is pertinent to CDC25B localization at the centrosome. We further demonstrate that CDC25B plays a role in maintaining the overall integrity of the centrosome, by regulating the centrosome levels of multiple centrosome proteins, including that of Ctn2. Conclusions. Our results therefore suggest that CDC25B associates with a Ctn2-containing multiprotein complex in the cytoplasm, which targets it to the centrosome, where it plays a role in maintaining the centrosome levels of Ctn2 and a number of other centrosome components.
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Dantas TJ, Wang Y, Lalor P, Dockery P, Morrison CG. Defective nucleotide excision repair with normal centrosome structures and functions in the absence of all vertebrate centrins. ACTA ACUST UNITED AC 2011; 193:307-18. [PMID: 21482720 PMCID: PMC3080269 DOI: 10.1083/jcb.201012093] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Centrin-null cells undergo normal division but are highly sensitive to UV irradiation as a result of impaired DNA repair. The principal microtubule-organizing center in animal cells, the centrosome, contains centrin, a small, conserved calcium-binding protein unique to eukaryotes. Several centrin isoforms exist and have been implicated in various cellular processes including nuclear export and deoxyribonucleic acid (DNA) repair. Although centrins are required for centriole/basal body duplication in lower eukaryotes, centrin functions in vertebrate centrosome duplication are less clear. To define these roles, we used gene targeting in the hyperrecombinogenic chicken DT40 cell line to delete all three centrin genes in individual clones. Unexpectedly, centrin-deficient cells underwent normal cellular division with no detectable cell cycle defects. Light and electron microscopy analyses revealed no significant difference in centrosome composition or ultrastructure. However, centrin deficiency made DT40 cells highly sensitive to ultraviolet (UV) irradiation, with Cetn3 deficiency exacerbating the sensitivity of Cetn4/Cetn2 double mutants. DNA damage checkpoints were intact, but repair of UV-induced DNA damage was delayed in centrin nulls. These data demonstrate a role for vertebrate centrin in nucleotide excision repair.
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Affiliation(s)
- Tiago J Dantas
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway 091 524 411, Ireland
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Eckerdt F, Yamamoto TM, Lewellyn AL, Maller JL. Identification of a polo-like kinase 4-dependent pathway for de novo centriole formation. Curr Biol 2011; 21:428-32. [PMID: 21353560 PMCID: PMC3093158 DOI: 10.1016/j.cub.2011.01.072] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Revised: 12/30/2010] [Accepted: 01/28/2011] [Indexed: 12/26/2022]
Abstract
Supernumerary centrosomes are a key cause of genomic instability in cancer cells. New centrioles can be generated by duplication with a mother centriole as a platform or, in the absence of preexisting centrioles, by formation de novo. Polo-like kinase 4 (Plk4) regulates both modes of centriole biogenesis, and Plk4 deregulation has been linked to tumor development. We show that Plx4, the Xenopus homolog of mammalian Plk4 and Drosophila Sak, induces de novo centriole formation in vivo in activated oocytes and in egg extracts, but not in immature or in vitro matured oocytes. Both kinase activity and the polo-box domain of Plx4 are required for de novo centriole biogenesis. Polarization microscopy in "cycling" egg extracts demonstrates that de novo centriole formation is independent of Cdk2 activity, a major difference compared to template-driven centrosome duplication that is linked to the nuclear cycle and requires cyclinA/E/Cdk2. Moreover, we show that the Mos-MAPK pathway blocks Plx4-dependent de novo centriole formation before fertilization, thereby ensuring paternal inheritance of the centrosome. The results define a new system for studying the biochemical and molecular basis of de novo centriole formation and centriole biogenesis in general.
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Affiliation(s)
- Frank Eckerdt
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045
| | - Tomomi M. Yamamoto
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045
| | - Andrea L. Lewellyn
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045
| | - James L. Maller
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045
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Abstract
Malaria is caused by intraerythrocytic protozoan parasites belonging to Plasmodium spp. (phylum Apicomplexa) that produce significant morbidity and mortality, mostly in developing countries. Plasmodium parasites have a complex life cycle that includes multiple stages in anopheline mosquito vectors and vertebrate hosts. During the life cycle, the parasites undergo several cycles of extreme population growth within a brief span, and this is critical for their continued transmission and a contributing factor for their pathogenesis in the host. As with other eukaryotes, successful mitosis is an essential requirement for Plasmodium reproduction; however, some aspects of Plasmodium mitosis are quite distinct and not fully understood. In this review, we will discuss the current understanding of the architecture and key events of mitosis in Plasmodium falciparum and related parasites and compare them with the traditional mitotic events described for other eukaryotes.
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Tanaka N, Goto M, Kawasaki A, Sasano T, Eto K, Nishi R, Sugasawa K, Abe S, Saitoh H. An EF-hands protein, centrin-1, is an EGTA-sensitive SUMO-interacting protein in mouse testis. Cell Biochem Funct 2011; 28:604-12. [PMID: 20941751 DOI: 10.1002/cbf.1698] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
A multifunctional calcium-binding protein, centrin-1, is specifically expressed in male germ cells, certain neurons and ciliated cells. We identified centrin-1 as a protein interacting with SUMO-2/3 using yeast two-hybrid screening of a mouse testicular cDNA library. In bead halo assays, the interaction between centrin-1 and SUMO-2/3 was reduced in the presence of EGTA and facilitated by the addition of CaCl₂. immunostaining of seminiferous tubules in 35-day-old mouse testes revealed that cells in the layer containing spermatogonia showed colocalization of SUMO-2/3 with centrin-1 in cytoplasmic spots. Identification of centrin-1 as the EGTA-sensitive SUMO-2/3-interacting protein indicates the possible role of calcium in modulating the centrin-1-SUMO-2/3 interaction and suggests the importance of this interaction in mouse testis.
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Affiliation(s)
- Niina Tanaka
- Department of Biological Sciences, Graduate School of Science and Technology, Kumamoto University, Kumamoto, Japan
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34
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A Global Expression Switch Marks Pachytene Initiation during Mouse Male Meiosis. Genes (Basel) 2010; 1:469-83. [PMID: 24710097 PMCID: PMC3966219 DOI: 10.3390/genes1030469] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Revised: 11/19/2010] [Accepted: 12/01/2010] [Indexed: 12/04/2022] Open
Abstract
Male spermatogenesis is an essential and complex process necessary to gain totipotency and allow a whole new organism to develop upon fertilization. While single-gene based studies have provided insights into the mechanisms underlying spermatogenesis, detailed global profiling of all the key meiotic stages is required to fully define these processes. Here, by isolating highly enriched mouse meiotic cell populations, we have generated a comprehensive gene expression atlas of mammalian meiosis. Our data define unique signatures for the specific stages of meiosis, including global chromosome X inactivation and reactivation. The data also reveal profound switches in global gene expression at the initiation of pachynema that are reminiscent of the commitment to meiosis observed in budding yeast. Overall, this meiotic atlas provides an exhaustive blueprint and resource for mammalian gametogenesis and meiosis.
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Brun E, Blouquit Y, Duchambon P, Malosse C, Chamot-Rooke J, Sicard-Roselli C. Oxidative stress induces mainly human centrin 2 polymerisation. Int J Radiat Biol 2010; 86:657-68. [PMID: 20586543 DOI: 10.3109/09553001003734584] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
PURPOSE To determine the human centrin 2 (Hscen 2) protein response to oxidising radicals in vitro and to evaluate the consequences on its biological functions. MATERIALS AND METHODS Hscen 2 was submitted to hydroxyl and azide radicals produced by radiolysis in the absence of oxygen. The resulting products were characterised by biochemical, spectroscopic and mass spectrometry techniques. Their thermodynamics parameters of complexation with C-terminal fragment of Xeroderma pigmentosum C protein (C-XPC), one of the Hscen 2 cellular partners, were quantified by isothermal titration calorimetry (ITC). RESULTS Both hydroxyl and azide radicals induce centrin 2 polymerisation as we characterised several intermolecular cross-links generating dimers, trimers, tetramers and higher molecular mass species. These cross-links result from the formation of a covalent bond between the only tyrosine residue (Tyr 172) located in the C-terminal region of each monomer. Remarkably, dimerisation occurs for doses as low as a few grays. Moreover, this Hscen2 dimer has a lower affinity and stoechiometry binding to C-XPC. CONCLUSIONS These results show that as oxidative radicals induce high proportions of irreversible damages (polymerisation) centrin 2 is highly sensitive to ionising radiation. This could have important consequences on its biological functions.
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Affiliation(s)
- Emilie Brun
- Laboratoire de Chimie Physique, CNRS UMR 8000, Université Paris-Sud 11, Bât. 350, Orsay Cedex, France
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Kanai M, Crowe MS, Zheng Y, Vande Woude GF, Fukasawa K. RhoA and RhoC are both required for the ROCK II-dependent promotion of centrosome duplication. Oncogene 2010; 29:6040-50. [PMID: 20697357 PMCID: PMC2978787 DOI: 10.1038/onc.2010.328] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
CDK2-cyclin E triggers centrosome duplication, and nucleophosmin (NPM/B23) is found to be one of its targets. NPM/B23 phosphorylated by CDK2-cyclin E acquires a high binding affinity to Rho-associated kinase (ROCK II), and physically associates with ROCK II. The NPM/B23-binding results in super-activation of ROCK II, which is a critical event for initiation of centrosome duplication. The activation of ROCK II also requires the binding of Rho small GTPase to the auto-inhibitory region; hence the availability of the active Rho protein is an important aspect of the centrosomally localized ROCK II to properly initiate centrosome duplication. There are three isoforms of Rho (RhoA, B, and C), all of which are capable of binding to and priming the activation of ROCK II. Here, we investigated which Rho isoform(s) are involved in the activation of ROCK II in respect to the initiation of centrosome duplication. We found that both RhoA and RhoC, but not RhoB, were required for initiation of centrosome duplication, and over-activation of RhoA as well as RhoC, but not RhoB, promoted centrosome duplication and centrosome amplification.
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Affiliation(s)
- M Kanai
- Molecular Oncology Program, H Lee Moffitt Cancer Center & Research Institute, Tampa, FL 33612, USA
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Sargent LM, Reynolds SH, Castranova V. Potential pulmonary effects of engineered carbon nanotubes:in vitrogenotoxic effects. Nanotoxicology 2010; 4:396-408. [DOI: 10.3109/17435390.2010.500444] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Radu L, Durussel I, Assairi L, Blouquit Y, Miron S, Cox JA, Craescu CT. Scherffelia dubia Centrin Exhibits a Specific Mechanism for Ca2+-Controlled Target Binding. Biochemistry 2010; 49:4383-94. [DOI: 10.1021/bi901764m] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Laura Radu
- Institut Curie Centre de Recherche, Centre Universitaire Paris-Sud, 91405 Orsay Cedex, France
- INSERM U759, Centre Universitaire Paris-Sud, 91405 Orsay Cedex, France
| | - Isabelle Durussel
- Department of Biochemistry, University of Geneva, Geneva 4, Switzerland
| | - Liliane Assairi
- Institut Curie Centre de Recherche, Centre Universitaire Paris-Sud, 91405 Orsay Cedex, France
- INSERM U759, Centre Universitaire Paris-Sud, 91405 Orsay Cedex, France
| | - Yves Blouquit
- Institut Curie Centre de Recherche, Centre Universitaire Paris-Sud, 91405 Orsay Cedex, France
- INSERM U759, Centre Universitaire Paris-Sud, 91405 Orsay Cedex, France
| | - Simona Miron
- Institut Curie Centre de Recherche, Centre Universitaire Paris-Sud, 91405 Orsay Cedex, France
- INSERM U759, Centre Universitaire Paris-Sud, 91405 Orsay Cedex, France
| | - Jos A. Cox
- Department of Biochemistry, University of Geneva, Geneva 4, Switzerland
| | - Constantin T. Craescu
- Institut Curie Centre de Recherche, Centre Universitaire Paris-Sud, 91405 Orsay Cedex, France
- INSERM U759, Centre Universitaire Paris-Sud, 91405 Orsay Cedex, France
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Zhou Q, Gheiratmand L, Chen Y, Lim TK, Zhang J, Li S, Xia N, Liu B, Lin Q, He CY. A comparative proteomic analysis reveals a new bi-lobe protein required for bi-lobe duplication and cell division in Trypanosoma brucei. PLoS One 2010; 5:e9660. [PMID: 20300570 PMCID: PMC2837748 DOI: 10.1371/journal.pone.0009660] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2009] [Accepted: 02/19/2010] [Indexed: 11/19/2022] Open
Abstract
A Golgi-associated bi-lobed structure was previously found to be important for Golgi duplication and cell division in Trypanosoma brucei. To further understand its functions, comparative proteomics was performed on extracted flagellar complexes (including the flagellum and flagellum-associated structures such as the basal bodies and the bi-lobe) and purified flagella to identify new bi-lobe proteins. A leucine-rich repeats containing protein, TbLRRP1, was characterized as a new bi-lobe component. The anterior part of the TbLRRP1-labeled bi-lobe is adjacent to the single Golgi apparatus, and the posterior side is tightly associated with the flagellar pocket collar marked by TbBILBO1. Inducible depletion of TbLRRP1 by RNA interference inhibited duplication of the bi-lobe as well as the adjacent Golgi apparatus and flagellar pocket collar. Formation of a new flagellum attachment zone and subsequent cell division were also inhibited, suggesting a central role of bi-lobe in Golgi, flagellar pocket collar and flagellum attachment zone biogenesis.
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Affiliation(s)
- Qing Zhou
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Ladan Gheiratmand
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Yixin Chen
- School of Life Sciences, Xiamen University, Xiamen, China
| | - Teck Kwang Lim
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Jun Zhang
- School of Life Sciences, Xiamen University, Xiamen, China
| | - Shaowei Li
- School of Life Sciences, Xiamen University, Xiamen, China
| | - Ningshao Xia
- School of Life Sciences, Xiamen University, Xiamen, China
| | - Binghai Liu
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Qingsong Lin
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Cynthia Y. He
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
- * E-mail:
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Cavalier-Smith T. Origin of the cell nucleus, mitosis and sex: roles of intracellular coevolution. Biol Direct 2010; 5:7. [PMID: 20132544 PMCID: PMC2837639 DOI: 10.1186/1745-6150-5-7] [Citation(s) in RCA: 139] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2009] [Accepted: 02/04/2010] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND The transition from prokaryotes to eukaryotes was the most radical change in cell organisation since life began, with the largest ever burst of gene duplication and novelty. According to the coevolutionary theory of eukaryote origins, the fundamental innovations were the concerted origins of the endomembrane system and cytoskeleton, subsequently recruited to form the cell nucleus and coevolving mitotic apparatus, with numerous genetic eukaryotic novelties inevitable consequences of this compartmentation and novel DNA segregation mechanism. Physical and mutational mechanisms of origin of the nucleus are seldom considered beyond the long-standing assumption that it involved wrapping pre-existing endomembranes around chromatin. Discussions on the origin of sex typically overlook its association with protozoan entry into dormant walled cysts and the likely simultaneous coevolutionary, not sequential, origin of mitosis and meiosis. RESULTS I elucidate nuclear and mitotic coevolution, explaining the origins of dicer and small centromeric RNAs for positionally controlling centromeric heterochromatin, and how 27 major features of the cell nucleus evolved in four logical stages, making both mechanisms and selective advantages explicit: two initial stages (origin of 30 nm chromatin fibres, enabling DNA compaction; and firmer attachment of endomembranes to heterochromatin) protected DNA and nascent RNA from shearing by novel molecular motors mediating vesicle transport, division, and cytoplasmic motility. Then octagonal nuclear pore complexes (NPCs) arguably evolved from COPII coated vesicle proteins trapped in clumps by Ran GTPase-mediated cisternal fusion that generated the fenestrated nuclear envelope, preventing lethal complete cisternal fusion, and allowing passive protein and RNA exchange. Finally, plugging NPC lumens by an FG-nucleoporin meshwork and adopting karyopherins for nucleocytoplasmic exchange conferred compartmentation advantages. These successive changes took place in naked growing cells, probably as indirect consequences of the origin of phagotrophy. The first eukaryote had 1-2 cilia and also walled resting cysts; I outline how encystation may have promoted the origin of meiotic sex. I also explain why many alternative ideas are inadequate. CONCLUSION Nuclear pore complexes are evolutionary chimaeras of endomembrane- and mitosis-related chromatin-associated proteins. The keys to understanding eukaryogenesis are a proper phylogenetic context and understanding organelle coevolution: how innovations in one cell component caused repercussions on others.
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Fryd-Versavel G, Lemullois M, Aubusson-Fleury A. Maintaining cell polarity through vegetative cell pattern dedifferentiation: cytoskeleton and morphogenesis in the hypotrich ciliate Sterkiella histriomuscorum. Protist 2009; 161:222-36. [PMID: 20022806 DOI: 10.1016/j.protis.2009.11.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2009] [Accepted: 10/06/2009] [Indexed: 11/17/2022]
Abstract
The morphological differentiation of ciliates is achieved through the development of a submembraneous cytoskeleton in which the cilia are anchored. In most hypotrich ciliates, this cytoskeleton is mainly constructed of microtubules. In these species, cells pass through vegetative cell pattern dedifferentiated stages during their biological cycle. In order to investigate the behaviour of the cytoskeleton during these stages, we analysed the reorganization of the cytoskeleton during the sexual cycle of Sterkiella histriomuscorum by microscopy. Sterkiella exconjugants transiently dedifferentiate to form zygocysts devoid of ciliature and infraciliature. Immunofluorescence images obtained with antibodies directed against pericentrosomal material and tubulin showed that the cells resorb their ciliature and basal bodies, but retain their submembraneous microtubular cytoskeleton during the whole process and that the body plan is maintained through vegetative cell pattern dedifferentiation: the cell polarity remains printed on the cell surface by the microtubular cytoskeleton which in turn could mark the sites of basal body assembly during zygocyst morphogenesis. The results are discussed in terms of mechanisms of cell patterning.
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Affiliation(s)
- Ghislaine Fryd-Versavel
- UMR8080 Développement, Morphogenèse et Evolution, Bat 444, Faculté d'Orsay, Université Paris XI, 91405 Orsay Cedex, France
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Abstract
Centrins are multifunctional Ca(2+)-binding proteins that are highly conserved from yeast to humans. Centrin-2 is a core component of the centrosome of higher eukaryotes. In addition, it is present within the nucleus, in which it is part of the xeroderma pigmentosum group C (XPC) complex, which controls nucleotide excision repair (NER). Regulation of the subcellular distribution of centrin-2 has so far remained elusive. Here we show that centrin-2 is a substrate of SUMOylation in vitro and in vivo, and that it is preferentially modified by SUMO2/3. Moreover, we identify the SUMO E3-like ligase human polycomb protein 2 (PC2; also known as hPC2) as essential for centrin-2 modification. Interference with the SUMOylation pathway leads to a striking defect in nuclear localization of centrin-2 and accumulation in the cytoplasm, whereas centrosomal recruitment of centrin-2 is unaffected. Depletion of the XPC protein mimics this situation and we provide evidence that SUMO conjugation of centrin-2 enhances its binding to the XPC protein. These data show that the nucleocytoplasmic shuttling of centrin-2 depends on the SUMO system and indicates that localization of centrin-2 within the nucleus depends on its ability to bind to the XPC protein.
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Affiliation(s)
- Ulf R Klein
- Department of Cell Biology, Max-Planck Institute of Biochemistry, D-82152 Martinsried, Germany.
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Molecular dissection of the centrosome overduplication pathway in S-phase-arrested cells. Mol Cell Biol 2009; 29:1760-73. [PMID: 19139275 DOI: 10.1128/mcb.01124-08] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Cancer cells frequently exhibit overduplicated centrosomes that lead to formation of multipolar spindles, chromosome missegregation, and aneuploidy. However, the molecular events involved in centrosome overduplication remain largely unknown. Experimentally, centrosome overduplication is observed in p53-deficient cells arrested in S phase with hydroxyurea. Using this assay, we have identified distinct roles for Cdk2, microtubules, dynein, and Hsp90 in the overduplication of functional centrosomes in mammalian cells and show that Cdk2 is also required for the generation of centriolar satellites. Moreover, we demonstrate that nuclear export is required for centriolar satellite formation and centrosome overduplication, with export inhibitors causing a Cdk-dependent accumulation of nuclear centrin granules. Hence, we propose that centrosome precursors may arise in the nucleus, providing a novel mechanistic explanation for how nuclear Cdk2 can promote centrosome overduplication in the cytoplasm. Furthermore, this study defines a molecular pathway that may be targeted to prevent centrosome overduplication in S-phase-arrested cancer cells.
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45
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Cavalier-Smith T. Predation and eukaryote cell origins: a coevolutionary perspective. Int J Biochem Cell Biol 2008; 41:307-22. [PMID: 18935970 DOI: 10.1016/j.biocel.2008.10.002] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2008] [Revised: 10/06/2008] [Accepted: 10/08/2008] [Indexed: 12/23/2022]
Abstract
Cells are of only two kinds: bacteria, with DNA segregated by surface membrane motors, dating back approximately 3.5Gy; and eukaryotes, which evolved from bacteria, possibly as recently as 800-850My ago. The last common ancestor of eukaryotes was a sexual phagotrophic protozoan with mitochondria, one or two centrioles and cilia. Conversion of bacteria (=prokaryotes) into a eukaryote involved approximately 60 major innovations. Numerous contradictory ideas about eukaryogenesis fail to explain fundamental features of eukaryotic cell biology or conflict with phylogeny. Data are best explained by the intracellular coevolutionary theory, with three basic tenets: (1) the eukaryotic cytoskeleton and endomembrane system originated through cooperatively enabling the evolution of phagotrophy; (2) phagocytosis internalised DNA-membrane attachments, unavoidably disrupting bacterial division; recovery entailed the evolution of the nucleus and mitotic cycle; (3) the symbiogenetic origin of mitochondria immediately followed the perfection of phagotrophy and intracellular digestion, contributing greater energy efficiency and group II introns as precursors of spliceosomal introns. Eukaryotes plus their archaebacterial sisters form the clade neomura, which evolved from a radically modified derivative of an actinobacterial posibacterium that had replaced the ancestral eubacterial murein peptidoglycan by N-linked glycoproteins, radically modified its DNA-handling enzymes, and evolved cotranslational protein secretion, but not the isoprenoid-ether lipids of archaebacteria. I focus on this phylogenetic background and on explaining how in response to novel phagotrophic selective pressures and ensuing genome internalisation this prekaryote evolved efficient digestion of prey proteins by retrotranslocation and 26S proteasomes, then internal digestion by phagocytosis, lysosomes, and peroxisomes, and eukaryotic vesicle trafficking and intracellular compartmentation.
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Affiliation(s)
- T Cavalier-Smith
- Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK.
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Trojan P, Rausch S, Gieβl A, Klemm C, Krause E, Pulvermüller A, Wolfrum U. Light-dependent CK2-mediated phosphorylation of centrins regulates complex formation with visual G-protein. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2008; 1783:1248-60. [DOI: 10.1016/j.bbamcr.2008.01.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2007] [Revised: 12/21/2007] [Accepted: 01/03/2008] [Indexed: 11/16/2022]
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Trojan P, Krauss N, Choe HW, Giessl A, Pulvermüller A, Wolfrum U. Centrins in retinal photoreceptor cells: regulators in the connecting cilium. Prog Retin Eye Res 2008; 27:237-59. [PMID: 18329314 DOI: 10.1016/j.preteyeres.2008.01.003] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Changes in the intracellular Ca2+ concentration regulate the visual signal transduction cascade directly or more often indirectly through Ca2+-binding proteins. Here we focus on centrins, which are members of a highly conserved subgroup of the EF-hand superfamily of Ca2+-binding proteins in photoreceptor cells of the vertebrate retina. Centrins are commonly associated with centrosome-related structures. In mammalian retinal photoreceptor cells, four centrin isoforms are expressed as prominent components in the connecting cilium linking the light-sensitive outer segment compartment with the metabolically active inner segment compartment. Our data indicate that Ca2+-activated centrin isoforms assemble into protein complexes with the visual heterotrimeric G-protein transducin. This interaction of centrins with transducin is mediated by binding to the betagamma-dimer of the heterotrimeric G-protein. More recent findings show that these interactions of centrins with transducin are reciprocally regulated via site-specific phosphorylations mediated by the protein kinase CK2. The assembly of centrin/G-protein complexes is a novel aspect of translocation regulation of signalling proteins in sensory cells, and represents a potential link between molecular trafficking and signal transduction in general.
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Affiliation(s)
- Philipp Trojan
- Institut für Zoologie, Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany
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Abstract
The cilium is a characteristic organelle of eukaryotes constructed from over 600 proteins. Bacterial flagella are entirely different. 9 + 2 motile cilia evolved before the divergence of the last eukaryotic common ancestor (LECA). This chapter explores, compares, and contrasts two potential pathways of evolution: (1) via invasion of a centriolar-like virus and (2) via autogenous formation from a pre-existing microtubule-organizing center (MTOC). In either case, the intraflagellar transport (IFT) machinery that is nearly universally required for the assembly and maintenance of cilia derived from the evolving intracellular vesicular transport system. The sensory function of cilia evolved first and the ciliary axoneme evolved gradually with ciliary motility, an important selection mechanism, as one of the driving forces.
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Affiliation(s)
- Peter Satir
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, New York, USA
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