1
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Saju A, Chen PP, Weng TH, Tsai SY, Tanaka A, Tseng YT, Chang CC, Wang CH, Shimamoto Y, Hsia KC. HURP binding to the vinca domain of β-tubulin accounts for cancer drug resistance. Nat Commun 2024; 15:8844. [PMID: 39397030 PMCID: PMC11471760 DOI: 10.1038/s41467-024-53139-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Accepted: 09/30/2024] [Indexed: 10/15/2024] Open
Abstract
Vinca alkaloids, a class of tubulin-binding agent, are widely used in treating cancer, yet the emerging resistance compromises their efficacy. Hepatoma up-regulated protein (HURP), a microtubule-associated protein displaying heightened expression across various cancer types, reduces cancer cells' sensitivity to vinca-alkaloid drugs upon overexpression. However, the molecular basis behind this drug resistance remains unknown. Here we discover a tubulin-binding domain within HURP, and establish its role in regulating microtubule growth. Cryo-EM analysis reveals interactions between HURP's tubulin-binding domain and the vinca domain on β-tubulin -- the site targeted by vinca alkaloid drugs. Importantly, HURP competes directly with vinorelbine, a vinca alkaloid-based chemotherapeutic agent, countering microtubule growth defects caused by vinorelbine both in vitro and in vivo. Our findings elucidate a mechanism driving drug resistance in HURP-overexpressing cancer cells and emphasize HURP tubulin-binding domain's role in mitotic spindle assembly. This underscores its potential as a therapeutic target to improve cancer treatment.
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Affiliation(s)
- Athira Saju
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
- Molecular and Cell Biology, Taiwan International Graduate Program and National Defense Medical Center, Taipei, Taiwan
| | - Po-Pang Chen
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
- Institute of Biochemistry and Molecular biology, College of Life Sciences, National Yang-Ming Chiao-Tung University, Hsinchu, Taiwan
| | - Tzu-Han Weng
- Department of Life Science, National Taiwan University, Taipei, 10617, Taiwan
| | - Su-Yi Tsai
- Department of Life Science, National Taiwan University, Taipei, 10617, Taiwan
| | - Akihiro Tanaka
- Department of Chromosome Science, National Institute of Genetics, Shizuoka, Japan
| | - Yu-Ting Tseng
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Chih-Chia Chang
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Chun-Hsiung Wang
- Institute of Biological Chemistry, Academia Sinica, Taipei, 11529, Taiwan
| | - Yuta Shimamoto
- Department of Chromosome Science, National Institute of Genetics, Shizuoka, Japan
| | - Kuo-Chiang Hsia
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan.
- Molecular and Cell Biology, Taiwan International Graduate Program and National Defense Medical Center, Taipei, Taiwan.
- Institute of Biochemistry and Molecular biology, College of Life Sciences, National Yang-Ming Chiao-Tung University, Hsinchu, Taiwan.
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2
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Kiyomitsu A, Nishimura T, Hwang SJ, Ansai S, Kanemaki MT, Tanaka M, Kiyomitsu T. Ran-GTP assembles a specialized spindle structure for accurate chromosome segregation in medaka early embryos. Nat Commun 2024; 15:981. [PMID: 38302485 PMCID: PMC10834446 DOI: 10.1038/s41467-024-45251-w] [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: 07/09/2023] [Accepted: 01/19/2024] [Indexed: 02/03/2024] Open
Abstract
Despite drastic cellular changes during cleavage, a mitotic spindle assembles in each blastomere to accurately segregate duplicated chromosomes. Mechanisms of mitotic spindle assembly have been extensively studied using small somatic cells. However, mechanisms of spindle assembly in large vertebrate embryos remain little understood. Here, we establish functional assay systems in medaka (Oryzias latipes) embryos by combining CRISPR knock-in with auxin-inducible degron technology. Live imaging reveals several unexpected features of microtubule organization and centrosome positioning that achieve rapid, accurate cleavage. Importantly, Ran-GTP assembles a dense microtubule network at the metaphase spindle center that is essential for chromosome segregation in early embryos. This unique spindle structure is remodeled into a typical short, somatic-like spindle after blastula stages, when Ran-GTP becomes dispensable for chromosome segregation. We propose that despite the presence of centrosomes, the chromosome-derived Ran-GTP pathway has essential roles in functional spindle assembly in large, rapidly dividing vertebrate early embryos, similar to acentrosomal spindle assembly in oocytes.
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Affiliation(s)
- Ai Kiyomitsu
- Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Kunigami-gun, Okinawa, 904-0495, Japan
| | - Toshiya Nishimura
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya, 464-8602, Japan
- Hokkaido University Fisheries Sciences, 3-1-1, Minato-cho, Hakodate, Hokkaido, 041-8611, Japan
| | - Shiang Jyi Hwang
- Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Kunigami-gun, Okinawa, 904-0495, Japan
| | - Satoshi Ansai
- Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi, 980-8577, Japan
- Laboratory of Genome Editing Breeding, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, 606-8507, Japan
| | - Masato T Kanemaki
- Department of Chromosome Science, National Institute of Genetics, Research Organization of Information and Systems (ROIS), and Graduate Institute for Advanced Studies, SOKENDAI, Yata 1111, Mishima, Shizuoka, 411-8540, Japan
- Department of Biological Science, The University of Tokyo, Tokyo, 113-0033, Japan
| | - Minoru Tanaka
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya, 464-8602, Japan
| | - Tomomi Kiyomitsu
- Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Kunigami-gun, Okinawa, 904-0495, Japan.
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3
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Valdez V, Ma M, Gouveia B, Zhang R, Petry S. HURP facilitates spindle assembly by stabilizing microtubules and working synergistically with TPX2. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.18.571906. [PMID: 38187686 PMCID: PMC10769297 DOI: 10.1101/2023.12.18.571906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
In large vertebrate spindles, the majority of microtubules are formed via branching microtubule nucleation, whereby microtubules nucleate along the side of pre-existing microtubules. Hepatoma up-regulated protein (HURP) is a microtubule-associated protein that has been implicated in spindle assembly, but its mode of action is yet to be defined. In this study, we show that HURP is necessary for RanGTP-induced branching microtubule nucleation in Xenopus egg extract. Specifically, HURP stabilizes the microtubule lattice to promote microtubule formation from γ-TuRC. This function is shifted to promote branching microtubule nucleation in the presence of TPX2, another branching-promoting factor, as HURP's localization to microtubules is enhanced by TPX2 condensation. Lastly, we provide a structure of HURP on the microtubule lattice, revealing how HURP binding stabilizes the microtubule lattice. We propose a model in which HURP stabilizes microtubules during their formation, and TPX2 preferentially enriches HURP to microtubules to promote branching microtubule nucleation and thus spindle assembly.
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Affiliation(s)
- Venecia Valdez
- Princeton University, Department of Molecular Biology, Princeton, New Jersey, United States
| | - Meisheng Ma
- Department of Biochemistry and Molecular Biophysics, Washington University in St. Louis, School of Medicine (St. Louis, Missouri, United States)
- Present address: Department of Histology and Embryology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology (Wuhan, Hubei, China)
| | - Bernardo Gouveia
- Princeton University, Department of Chemical and Biological Engineering, Princeton, New Jersey, United States
| | - Rui Zhang
- Department of Biochemistry and Molecular Biophysics, Washington University in St. Louis, School of Medicine (St. Louis, Missouri, United States)
| | - Sabine Petry
- Princeton University, Department of Molecular Biology, Princeton, New Jersey, United States
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4
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Valdez VA, Neahring L, Petry S, Dumont S. Mechanisms underlying spindle assembly and robustness. Nat Rev Mol Cell Biol 2023; 24:523-542. [PMID: 36977834 PMCID: PMC10642710 DOI: 10.1038/s41580-023-00584-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/30/2023] [Indexed: 03/30/2023]
Abstract
The microtubule-based spindle orchestrates chromosome segregation during cell division. Following more than a century of study, many components and pathways contributing to spindle assembly have been described, but how the spindle robustly assembles remains incompletely understood. This process involves the self-organization of a large number of molecular parts - up to hundreds of thousands in vertebrate cells - whose local interactions give rise to a cellular-scale structure with emergent architecture, mechanics and function. In this Review, we discuss key concepts in our understanding of spindle assembly, focusing on recent advances and the new approaches that enabled them. We describe the pathways that generate the microtubule framework of the spindle by driving microtubule nucleation in a spatially controlled fashion and present recent insights regarding the organization of individual microtubules into structural modules. Finally, we discuss the emergent properties of the spindle that enable robust chromosome segregation.
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Affiliation(s)
| | - Lila Neahring
- Department of Bioengineering & Therapeutic Sciences, UCSF, San Francisco, CA, USA
- Developmental & Stem Cell Biology Graduate Program, UCSF, San Francisco, CA, USA
| | - Sabine Petry
- Molecular Biology, Princeton University, Princeton, NJ, USA.
| | - Sophie Dumont
- Department of Bioengineering & Therapeutic Sciences, UCSF, San Francisco, CA, USA.
- Developmental & Stem Cell Biology Graduate Program, UCSF, San Francisco, CA, USA.
- Department of Biochemistry & Biophysics, UCSF, San Francisco, CA, USA.
- Chan Zuckerberg Biohub, San Francisco, CA, USA.
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5
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Didaskalou S, Efstathiou C, Galtsidis S, Kesisova I, Halavatyi A, Elmali T, Tsolou A, Girod A, Koffa M. HURP localization in metaphase is the result of a multi-step process requiring its phosphorylation at Ser627 residue. Front Cell Dev Biol 2023; 11:981425. [PMID: 37484914 PMCID: PMC10361663 DOI: 10.3389/fcell.2023.981425] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 06/20/2023] [Indexed: 07/25/2023] Open
Abstract
Faithful chromosome segregation during cell division requires accurate mitotic spindle formation. As mitosis occurs rapidly within the cell cycle, the proteins involved in mitotic spindle assembly undergo rapid changes, including their interactions with other proteins. The proper localization of the HURP protein on the kinetochore fibers, in close proximity to chromosomes, is crucial for ensuring accurate congression and segregation of chromosomes. In this study, we employ photoactivation and FRAP experiments to investigate the impact of alterations in microtubule flux and phosphorylation of HURP at the Ser627 residue on its dynamics. Furthermore, through immunoprecipitations assays, we demonstrate the interactions of HURP with various proteins, such as TPX2, Aurora A, Eg5, Dynein, Kif5B, and Importin β, in mammalian cells during mitosis. We also find that phosphorylation of HURP at Ser627 regulates its interaction with these partners during mitosis. Our findings suggest that HURP participates in at least two distinct complexes during metaphase to ensure its proper localization in close proximity to chromosomes, thereby promoting the bundling and stabilization of kinetochore fibers.
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Affiliation(s)
- Stylianos Didaskalou
- Department of Molecular Biology and Genetics, Democritus University of Thrace, Alexandroupolis, Greece
| | - Christos Efstathiou
- Department of Molecular Biology and Genetics, Democritus University of Thrace, Alexandroupolis, Greece
- Department of Life Sciences and Medicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Sotirios Galtsidis
- Department of Life Sciences and Medicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Ilοna Kesisova
- Department of Molecular Biology and Genetics, Democritus University of Thrace, Alexandroupolis, Greece
- Department of Life Sciences and Medicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Aliaksandr Halavatyi
- Advanced Light Microscopy Facility, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Tountzai Elmali
- Department of Molecular Biology and Genetics, Democritus University of Thrace, Alexandroupolis, Greece
| | - Avgi Tsolou
- Department of Molecular Biology and Genetics, Democritus University of Thrace, Alexandroupolis, Greece
| | - Andreas Girod
- Department of Life Sciences and Medicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Maria Koffa
- Department of Molecular Biology and Genetics, Democritus University of Thrace, Alexandroupolis, Greece
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6
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Kraus J, Travis SM, King MR, Petry S. Augmin is a Ran-regulated spindle assembly factor. J Biol Chem 2023; 299:104736. [PMID: 37086784 DOI: 10.1016/j.jbc.2023.104736] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 04/03/2023] [Accepted: 04/05/2023] [Indexed: 04/24/2023] Open
Abstract
Mitotic spindles are composed of microtubules (MTs) that must nucleate at the right place and time. Ran regulates this process by directly controlling the release of spindle assembly factors (SAFs) from nucleocytoplasmic shuttle proteins importin-αβ and subsequently forms a biochemical gradient of SAFs localized around chromosomes. The majority of spindle MTs are generated by branching MT nucleation, which has been shown to require an eight-subunit protein complex known as augmin. InXenopus laevis, Ran can control branching through a canonical SAF, TPX2, which is non-essential in Drosophila melanogaster embryos and HeLa cells. Thus, how Ran regulates branching MT nucleation when TPX2 is not required remains unknown. Here, we use in vitro pulldowns and TIRF microscopy to show that augmin is a Ran-regulated SAF. We demonstrate that augmin directly interacts with both importin-α and importin-β through two nuclear localization sequences on the Haus8 subunit, which overlap with the MT binding site. Moreover, we show Ran controls localization of augmin to MTs in both Xenopus egg extract and in vitro. Our results demonstrate that RanGTP directly regulates augmin, which establishes a new way by which Ran controls branching MT nucleation and spindle assembly both in the absence and presence of TPX2.
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Affiliation(s)
- Jodi Kraus
- Department of Molecular Biology; Princeton University; Princeton, NJ, 08544; USA
| | - Sophie M Travis
- Department of Molecular Biology; Princeton University; Princeton, NJ, 08544; USA
| | - Matthew R King
- Department of Molecular Biology; Princeton University; Princeton, NJ, 08544; USA
| | - Sabine Petry
- Department of Molecular Biology; Princeton University; Princeton, NJ, 08544; USA.
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7
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van Toorn M, Gooch A, Boerner S, Kiyomitsu T. NuMA deficiency causes micronuclei via checkpoint-insensitive k-fiber minus-end detachment from mitotic spindle poles. Curr Biol 2023; 33:572-580.e2. [PMID: 36626904 DOI: 10.1016/j.cub.2022.12.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 12/01/2022] [Accepted: 12/08/2022] [Indexed: 01/11/2023]
Abstract
Micronuclei resulting from improper chromosome segregation foster chromosome rearrangements.1,2 To prevent micronuclei formation in mitosis, the dynamic plus ends of bundled kinetochore microtubules (k-fibers) must establish bipolar attachment with all sister kinetochores on chromosomes,3 whereas k-fiber minus ends must be clustered at the two opposing spindle poles, which are normally connected with centrosomes.4 The establishment of chromosome biorientation via k-fiber plus ends is carefully monitored by the spindle assembly checkpoint (SAC).5 However, how k-fiber minus-end clustering near centrosomes is maintained and monitored remains poorly understood. Here, we show that degradation of NuMA by auxin-inducible degron technologies results in micronuclei formation through k-fiber minus-end detachment from spindle poles during metaphase in HCT116 colon cancer cells. Importantly, k-fiber minus-end detachment from one pole creates misaligned chromosomes that maintain chromosome biorientation and satisfy the SAC, resulting in abnormal chromosome segregation. NuMA depletion also causes minus-end clustering defects in non-transformed Rpe1 cells, but it additionally induces centrosome detachment from partially focused poles, resulting in highly disorganized anaphase. Moreover, we find that NuMA depletion causes centrosome clustering defects in tetraploid-like cells, leading to an increased frequency of multipolar divisions. Together, our data indicate that NuMA is required for faithful chromosome segregation in human mitotic cells, generally by maintaining k-fiber minus-end clustering but also by promoting spindle pole-centrosome or centrosome-centrosome connection in specific cell types or contexts. Similar to erroneous merotelic kinetochore attachments,6 detachment of k-fiber minus ends from spindle poles evades spindle checkpoint surveillance and may therefore be a source of genomic instability in dividing cells.
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Affiliation(s)
- Marvin van Toorn
- Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Kunigami-gun, Okinawa 904-0495, Japan
| | - Amy Gooch
- Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Kunigami-gun, Okinawa 904-0495, Japan
| | - Susan Boerner
- Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Kunigami-gun, Okinawa 904-0495, Japan
| | - Tomomi Kiyomitsu
- Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Kunigami-gun, Okinawa 904-0495, Japan.
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8
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El-Tanani M, Nsairat H, Mishra V, Mishra Y, Aljabali AAA, Serrano-Aroca Á, Tambuwala MM. Ran GTPase and Its Importance in Cellular Signaling and Malignant Phenotype. Int J Mol Sci 2023; 24:ijms24043065. [PMID: 36834476 PMCID: PMC9968026 DOI: 10.3390/ijms24043065] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 01/10/2023] [Accepted: 01/11/2023] [Indexed: 02/08/2023] Open
Abstract
Ran is a member of the Ras superfamily of proteins, which primarily regulates nucleocytoplasmic trafficking and mediates mitosis by regulating spindle formation and nuclear envelope (NE) reassembly. Therefore, Ran is an integral cell fate determinant. It has been demonstrated that aberrant Ran expression in cancer is a result of upstream dysregulation of the expression of various factors, such as osteopontin (OPN), and aberrant activation of various signaling pathways, including the extracellular-regulated kinase/mitogen-activated protein kinase (ERK/MEK) and phosphatidylinositol 3-kinase/Protein kinase B (PI3K/Akt) pathways. In vitro, Ran overexpression has severe effects on the cell phenotype, altering proliferation, adhesion, colony density, and invasion. Therefore, Ran overexpression has been identified in numerous types of cancer and has been shown to correlate with tumor grade and the degree of metastasis present in various cancers. The increased malignancy and invasiveness have been attributed to multiple mechanisms. Increased dependence on Ran for spindle formation and mitosis is a consequence of the upregulation of these pathways and the ensuing overexpression of Ran, which increases cellular dependence on Ran for survival. This increases the sensitivity of cells to changes in Ran concentration, with ablation being associated with aneuploidy, cell cycle arrest, and ultimately, cell death. It has also been demonstrated that Ran dysregulation influences nucleocytoplasmic transport, leading to transcription factor misallocation. Consequently, patients with tumors that overexpress Ran have been shown to have a higher malignancy rate and a shorter survival time compared to their counterparts.
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Affiliation(s)
- Mohamed El-Tanani
- Pharmacological and Diagnostic Research Centre, Faculty of Pharmacy, Al-Ahliyya Amman University, Amman 19328, Jordan
- Correspondence:
| | - Hamdi Nsairat
- Pharmacological and Diagnostic Research Centre, Faculty of Pharmacy, Al-Ahliyya Amman University, Amman 19328, Jordan
| | - Vijay Mishra
- School of Pharmaceutical Sciences, Lovely Professional University, Phagwara 144411, India
| | - Yachana Mishra
- Department of Zoology, School of Bioengineering and Biosciences, Lovely Professional University, Phagwara 144411, India
| | - Alaa A. A. Aljabali
- Department of Pharmaceutics & Pharmaceutical Technology, Yarmouk University, Irbid 21163, Jordan
| | - Ángel Serrano-Aroca
- Biomaterials and Bioengineering Laboratory, Centro de Investigación Traslacional San Alberto Magno, Universidad Católica de Valencia San Vicente Mártir, c/Guillem de Castro 94, 46001 Valencia, Spain
| | - Murtaza M. Tambuwala
- Lincoln Medical School, University of Lincoln, Brayford Pool, Lincoln LN6 7TS, UK
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9
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Castrogiovanni C, Inchingolo AV, Harrison JU, Dudka D, Sen O, Burroughs NJ, McAinsh AD, Meraldi P. Evidence for a HURP/EB free mixed-nucleotide zone in kinetochore-microtubules. Nat Commun 2022; 13:4704. [PMID: 35948594 PMCID: PMC9365851 DOI: 10.1038/s41467-022-32421-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 07/28/2022] [Indexed: 12/02/2022] Open
Abstract
Current models infer that the microtubule-based mitotic spindle is built from GDP-tubulin with small GTP caps at microtubule plus-ends, including those that attach to kinetochores, forming the kinetochore-fibres. Here we reveal that kinetochore-fibres additionally contain a dynamic mixed-nucleotide zone that reaches several microns in length. This zone becomes visible in cells expressing fluorescently labelled end-binding proteins, a known marker for GTP-tubulin, and endogenously-labelled HURP - a protein which we show to preferentially bind the GDP microtubule lattice in vitro and in vivo. We find that in mitotic cells HURP accumulates on the kinetochore-proximal region of depolymerising kinetochore-fibres, whilst avoiding recruitment to nascent polymerising K-fibres, giving rise to a growing "HURP-gap". The absence of end-binding proteins in the HURP-gaps leads us to postulate that they reflect a mixed-nucleotide zone. We generate a minimal quantitative model based on the preferential binding of HURP to GDP-tubulin to show that such a mixed-nucleotide zone is sufficient to recapitulate the observed in vivo dynamics of HURP-gaps.
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Affiliation(s)
- Cédric Castrogiovanni
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, 1211, Geneva 4, Switzerland
- Translational Research Centre in Onco-hematology, Faculty of Medicine, University of Geneva, 1211, Geneva 4, Switzerland
| | - Alessio V Inchingolo
- Centre for Mechanochemical Cell Biology, University of Warwick, Coventry, UK
- Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, UK
| | - Jonathan U Harrison
- Centre for Mechanochemical Cell Biology, University of Warwick, Coventry, UK
- Mathematics Institute, University of Warwick, Coventry, UK
| | - Damian Dudka
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, 1211, Geneva 4, Switzerland
- Translational Research Centre in Onco-hematology, Faculty of Medicine, University of Geneva, 1211, Geneva 4, Switzerland
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Onur Sen
- Centre for Mechanochemical Cell Biology, University of Warwick, Coventry, UK
- Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, UK
| | - Nigel J Burroughs
- Centre for Mechanochemical Cell Biology, University of Warwick, Coventry, UK
- Mathematics Institute, University of Warwick, Coventry, UK
| | - Andrew D McAinsh
- Centre for Mechanochemical Cell Biology, University of Warwick, Coventry, UK.
- Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, UK.
| | - Patrick Meraldi
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, 1211, Geneva 4, Switzerland.
- Translational Research Centre in Onco-hematology, Faculty of Medicine, University of Geneva, 1211, Geneva 4, Switzerland.
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10
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Tsuchiya K, Goshima G. Microtubule-associated proteins promote microtubule generation in the absence of γ-tubulin in human colon cancer cells. J Cell Biol 2021; 220:e202104114. [PMID: 34779859 PMCID: PMC8598081 DOI: 10.1083/jcb.202104114] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 08/13/2021] [Accepted: 09/20/2021] [Indexed: 11/29/2022] Open
Abstract
The γ-tubulin complex acts as the predominant microtubule (MT) nucleator that initiates MT formation and is therefore an essential factor for cell proliferation. Nonetheless, cellular MTs are formed after experimental depletion of the γ-tubulin complex, suggesting that cells possess other factors that drive MT nucleation. Here, by combining gene knockout, auxin-inducible degron, RNA interference, MT depolymerization/regrowth assay, and live microscopy, we identified four microtubule-associated proteins (MAPs), ch-TOG, CLASP1, CAMSAPs, and TPX2, which are involved in γ-tubulin-independent MT generation in human colon cancer cells. In the mitotic MT regrowth assay, nucleated MTs organized noncentriolar MT organizing centers (ncMTOCs) in the absence of γ-tubulin. Depletion of CLASP1 or TPX2 substantially delayed ncMTOC formation, suggesting that these proteins might promote MT nucleation in the absence of γ-tubulin. In contrast, depletion of ch-TOG or CAMSAPs did not affect the timing of ncMTOC appearance. CLASP1 also accelerates γ-tubulin-independent MT regrowth during interphase. Thus, MT generation can be promoted by MAPs without the γ-tubulin template.
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Affiliation(s)
- Kenta Tsuchiya
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Japan
| | - Gohta Goshima
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Japan
- Sugashima Marine Biological Laboratory, Graduate School of Science, Nagoya University, Nagoya, Japan
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11
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Barisic M, Rajendraprasad G, Steblyanko Y. The metaphase spindle at steady state - Mechanism and functions of microtubule poleward flux. Semin Cell Dev Biol 2021; 117:99-117. [PMID: 34053864 DOI: 10.1016/j.semcdb.2021.05.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 05/13/2021] [Accepted: 05/13/2021] [Indexed: 11/24/2022]
Abstract
The mitotic spindle is a bipolar cellular structure, built from tubulin polymers, called microtubules, and interacting proteins. This macromolecular machine orchestrates chromosome segregation, thereby ensuring accurate distribution of genetic material into the two daughter cells during cell division. Powered by GTP hydrolysis upon tubulin polymerization, the microtubule ends exhibit a metastable behavior known as the dynamic instability, during which they stochastically switch between the growth and shrinkage phases. In the context of the mitotic spindle, dynamic instability is furthermore regulated by microtubule-associated proteins and motor proteins, which enables the spindle to undergo profound changes during mitosis. This highly dynamic behavior is essential for chromosome capture and congression in prometaphase, as well as for chromosome alignment to the spindle equator in metaphase and their segregation in anaphase. In this review we focus on the mechanisms underlying microtubule dynamics and sliding and their importance for the maintenance of shape, structure and dynamics of the metaphase spindle. We discuss how these spindle properties are related to the phenomenon of microtubule poleward flux, highlighting its highly cooperative molecular basis and role in keeping the metaphase spindle at a steady state.
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Affiliation(s)
- Marin Barisic
- Cell Division and Cytoskeleton, Danish Cancer Society Research Center (DCRC), Strandboulevarden 49, 2100 Copenhagen, Denmark; Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark.
| | - Girish Rajendraprasad
- Cell Division and Cytoskeleton, Danish Cancer Society Research Center (DCRC), Strandboulevarden 49, 2100 Copenhagen, Denmark
| | - Yulia Steblyanko
- Cell Division and Cytoskeleton, Danish Cancer Society Research Center (DCRC), Strandboulevarden 49, 2100 Copenhagen, Denmark
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Kiyomitsu T, Boerner S. The Nuclear Mitotic Apparatus (NuMA) Protein: A Key Player for Nuclear Formation, Spindle Assembly, and Spindle Positioning. Front Cell Dev Biol 2021; 9:653801. [PMID: 33869212 PMCID: PMC8047419 DOI: 10.3389/fcell.2021.653801] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 03/10/2021] [Indexed: 01/10/2023] Open
Abstract
The nuclear mitotic apparatus (NuMA) protein is well conserved in vertebrates, and dynamically changes its subcellular localization from the interphase nucleus to the mitotic/meiotic spindle poles and the mitotic cell cortex. At these locations, NuMA acts as a key structural hub in nuclear formation, spindle assembly, and mitotic spindle positioning, respectively. To achieve its variable functions, NuMA interacts with multiple factors, including DNA, microtubules, the plasma membrane, importins, and cytoplasmic dynein. The binding of NuMA to dynein via its N-terminal domain drives spindle pole focusing and spindle positioning, while multiple interactions through its C-terminal region define its subcellular localizations and functions. In addition, NuMA can self-assemble into high-ordered structures which likely contribute to spindle positioning and nuclear formation. In this review, we summarize recent advances in NuMA’s domains, functions and regulations, with a focus on human NuMA, to understand how and why vertebrate NuMA participates in these functions in comparison with invertebrate NuMA-related proteins.
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Affiliation(s)
- Tomomi Kiyomitsu
- Cell Division Dynamics Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Japan
| | - Susan Boerner
- Cell Division Dynamics Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Japan
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