1
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Neahring L, Cho NH, He Y, Liu G, Fernandes J, Rux CJ, Nakos K, Subramanian R, Upadhyayula S, Yildiz A, Dumont S. Torques within and outside the human spindle balance twist at anaphase. J Cell Biol 2024; 223:e202312046. [PMID: 38869473 PMCID: PMC11176257 DOI: 10.1083/jcb.202312046] [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: 12/11/2023] [Revised: 05/14/2024] [Accepted: 05/30/2024] [Indexed: 06/14/2024] Open
Abstract
At each cell division, nanometer-scale motors and microtubules give rise to the micron-scale spindle. Many mitotic motors step helically around microtubules in vitro, and most are predicted to twist the spindle in a left-handed direction. However, the human spindle exhibits only slight global twist, raising the question of how these molecular torques are balanced. Here, we find that anaphase spindles in the epithelial cell line MCF10A have a high baseline twist, and we identify factors that both increase and decrease this twist. The midzone motors KIF4A and MKLP1 are together required for left-handed twist at anaphase, and we show that KIF4A generates left-handed torque in vitro. The actin cytoskeleton also contributes to left-handed twist, but dynein and its cortical recruitment factor LGN counteract it. Together, our work demonstrates that force generators regulate twist in opposite directions from both within and outside the spindle, preventing strong spindle twist during chromosome segregation.
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Affiliation(s)
- Lila Neahring
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA
- Developmental and Stem Cell Biology Graduate Program, University of California San Francisco, San Francisco, CA, USA
| | - Nathan H. Cho
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA
- Tetrad Graduate Program, University of California San Francisco, San Francisco, CA, USA
| | - Yifei He
- Department of Chemistry, University of California Berkeley, Berkeley, CA, USA
| | - Gaoxiang Liu
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, USA
| | - Jonathan Fernandes
- Department of Chemistry, University of California Berkeley, Berkeley, CA, USA
| | - Caleb J. Rux
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA
- UC Berkeley/UC San Francisco Graduate Group in Bioengineering, Berkeley, CA, USA
| | - Konstantinos Nakos
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Radhika Subramanian
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Srigokul Upadhyayula
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Chan Zuckerberg Biohub, San Francisco, CA, USA
| | - Ahmet Yildiz
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, USA
- Physics Department, University of California Berkeley, Berkeley, CA, USA
| | - Sophie Dumont
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA
- Developmental and Stem Cell Biology Graduate Program, University of California San Francisco, San Francisco, CA, USA
- Tetrad Graduate Program, University of California San Francisco, San Francisco, CA, USA
- UC Berkeley/UC San Francisco Graduate Group in Bioengineering, Berkeley, CA, USA
- Chan Zuckerberg Biohub, San Francisco, CA, USA
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA, USA
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2
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Meißner L, Niese L, Diez S. Helical motion and torque generation by microtubule motors. Curr Opin Cell Biol 2024; 88:102367. [PMID: 38735207 DOI: 10.1016/j.ceb.2024.102367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 04/15/2024] [Accepted: 04/16/2024] [Indexed: 05/14/2024]
Abstract
Microtubule motors play key roles in cellular functions, such as transport, mitosis and cell motility. Fueled by ATP hydrolysis, they convert chemical energy into mechanical work, which enables their movement on microtubules. While their motion along the long axis of microtubules has been studied extensively, some motors display an off-axis component, which results in helical motion around microtubules and the generation of torque in addition to linear forces. Understanding these nuanced movements expands our comprehension of motor protein dynamics and their impact on cellular processes.
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Affiliation(s)
- Laura Meißner
- B CUBE - Center for Molecular Bioengineering, TUD Dresden University of Technology, 01307 Dresden, Germany
| | - Lukas Niese
- B CUBE - Center for Molecular Bioengineering, TUD Dresden University of Technology, 01307 Dresden, Germany
| | - Stefan Diez
- B CUBE - Center for Molecular Bioengineering, TUD Dresden University of Technology, 01307 Dresden, Germany; Max Planck Institute for Molecular Cell Biology and Genetics, 01307 Dresden, Germany; Cluster of Excellence Physics of Life, TUD Dresden University of Technology, 01062 Dresden, Germany.
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3
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Shah H, Olivetta M, Bhickta C, Ronchi P, Trupinić M, Tromer EC, Tolić IM, Schwab Y, Dudin O, Dey G. Life-cycle-coupled evolution of mitosis in close relatives of animals. Nature 2024; 630:116-122. [PMID: 38778110 PMCID: PMC11153136 DOI: 10.1038/s41586-024-07430-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 04/16/2024] [Indexed: 05/25/2024]
Abstract
Eukaryotes have evolved towards one of two extremes along a spectrum of strategies for remodelling the nuclear envelope during cell division: disassembling the nuclear envelope in an open mitosis or constructing an intranuclear spindle in a closed mitosis1,2. Both classes of mitotic remodelling involve key differences in the core division machinery but the evolutionary reasons for adopting a specific mechanism are unclear. Here we use an integrated comparative genomics and ultrastructural imaging approach to investigate mitotic strategies in Ichthyosporea, close relatives of animals and fungi. We show that species in this clade have diverged towards either a fungal-like closed mitosis or an animal-like open mitosis, probably to support distinct multinucleated or uninucleated states. Our results indicate that multinucleated life cycles favour the evolution of closed mitosis.
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Affiliation(s)
- Hiral Shah
- Cell Biology and Biophysics, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany.
| | - Marine Olivetta
- Swiss Institute for Experimental Cancer Research, School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland
| | - Chandni Bhickta
- Cell Biology and Biophysics, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Paolo Ronchi
- Electron Microscopy Core Facility, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Monika Trupinić
- Division of Molecular Biology, Ruđer Bošković Institute (RBI), Zagreb, Croatia
| | - Eelco C Tromer
- Cell Biochemistry, Groningen Biomolecular Sciences & Biotechnology Institute, University of Groningen, Groningen, The Netherlands
| | - Iva M Tolić
- Division of Molecular Biology, Ruđer Bošković Institute (RBI), Zagreb, Croatia
| | - Yannick Schwab
- Cell Biology and Biophysics, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
- Electron Microscopy Core Facility, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Omaya Dudin
- Swiss Institute for Experimental Cancer Research, School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland.
| | - Gautam Dey
- Cell Biology and Biophysics, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany.
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4
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Meißner L, Niese L, Schüring I, Mitra A, Diez S. Human kinesin-5 KIF11 drives the helical motion of anti-parallel and parallel microtubules around each other. EMBO J 2024; 43:1244-1256. [PMID: 38424239 PMCID: PMC10987665 DOI: 10.1038/s44318-024-00048-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 01/24/2024] [Accepted: 01/29/2024] [Indexed: 03/02/2024] Open
Abstract
During mitosis, motor proteins and microtubule-associated protein organize the spindle apparatus by cross-linking and sliding microtubules. Kinesin-5 plays a vital role in spindle formation and maintenance, potentially inducing twist in the spindle fibers. The off-axis power stroke of kinesin-5 could generate this twist, but its implications in microtubule organization remain unclear. Here, we investigate 3D microtubule-microtubule sliding mediated by the human kinesin-5, KIF11, and found that the motor caused right-handed helical motion of anti-parallel microtubules around each other. The sidestepping ratio increased with reduced ATP concentration, indicating that forward and sideways stepping of the motor are not strictly coupled. Further, the microtubule-microtubule distance (motor extension) during sliding decreased with increasing sliding velocity. Intriguingly, parallel microtubules cross-linked by KIF11 orbited without forward motion, with nearly full motor extension. Altering the length of the neck linker increased the forward velocity and pitch of microtubules in anti-parallel overlaps. Taken together, we suggest that helical motion and orbiting of microtubules, driven by KIF11, contributes to flexible and context-dependent filament organization, as well as torque regulation within the mitotic spindle.
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Affiliation(s)
- Laura Meißner
- B CUBE - Center for Molecular Bioengineering, TUD Dresden University of Technology, 01307, Dresden, Germany
- BASS Center, Molecular Biophysics and Biochemistry Department, Yale University, 06511, New Haven, USA
| | - Lukas Niese
- B CUBE - Center for Molecular Bioengineering, TUD Dresden University of Technology, 01307, Dresden, Germany
| | - Irene Schüring
- B CUBE - Center for Molecular Bioengineering, TUD Dresden University of Technology, 01307, Dresden, Germany
| | - Aniruddha Mitra
- B CUBE - Center for Molecular Bioengineering, TUD Dresden University of Technology, 01307, Dresden, Germany
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, 3584CH, Utrecht, Netherlands
| | - Stefan Diez
- B CUBE - Center for Molecular Bioengineering, TUD Dresden University of Technology, 01307, Dresden, Germany.
- Max Planck Institute for Molecular Cell Biology and Genetics, 01307, Dresden, Germany.
- Cluster of Excellence Physics of Life, TUD Dresden University of Technology, 01062, Dresden, Germany.
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5
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Zekušić M, Bujić Mihica M, Skoko M, Vukušić K, Risteski P, Martinčić J, Tolić IM, Bendelja K, Ramić S, Dolenec T, Vrgoč Zimić I, Puljić D, Petric Vicković I, Iveković R, Batarilo I, Prosenc Zmrzljak U, Hoffmeister A, Vučemilo T. New characterization and safety evaluation of human limbal stem cells used in clinical application: fidelity of mitotic process and mitotic spindle morphologies. Stem Cell Res Ther 2023; 14:368. [PMID: 38093301 PMCID: PMC10720168 DOI: 10.1186/s13287-023-03586-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 11/23/2023] [Indexed: 12/17/2023] Open
Abstract
BACKGROUND Limbal stem cells (LSCs) are crucial for the regeneration of the corneal epithelium in patients with limbal stem cell deficiency (LSCD). Thus, LSCs during cultivation in vitro should be in highly homogeneous amounts, while potency and expression of stemness without tumorigenesis would be desirable. Therefore, further characterization and safety evaluation of engineered limbal grafts is required to provide safe and high-quality therapeutic applications. METHODS After in vitro expansion, LSCs undergo laboratory characterization in a single-cell suspension, cell culture, and in limbal grafts before transplantation. Using a clinically applicable protocol, the data collected on LSCs at passage 1 were summarized, including: identity (cell size, morphology); potency (yield, viability, population doubling time, colony-forming efficiency); expression of putative stem cell markers through flow cytometry, immunofluorescence, and immunohistochemistry. Then, mitotic chromosome stability and normal mitotic outcomes were explored by using live-cell imaging. Finally, impurities, bacterial endotoxins and sterility were determined. RESULTS Expression of the stemness marker p63 in single-cell suspension and in cell culture showed high values by different methods. Limbal grafts showed p63-positive cells (78.7 ± 9.4%), Ki67 proliferation (41.7 ± 15.9%), while CK3 was negative. Impurity with 3T3 feeder cells and endotoxins was minimized. We presented mitotic spindles with a length of 11.40 ± 0.54 m and a spindle width of 8.05 ± 0.55 m as new characterization in LSC culture. Additionally, live-cell imaging of LSCs (n = 873) was performed, and only a small fraction < 2.5% of aberrant interphase cells was observed; 2.12 ± 2.10% of mitotic spindles exhibited a multipolar phenotype during metaphase, and 3.84 ± 3.77% of anaphase cells had a DNA signal present within the spindle midzone, indicating a chromosome bridge or lagging chromosome phenotype. CONCLUSION This manuscript provides, for the first time, detailed characterization of the parameters of fidelity of the mitotic process and mitotic spindle morphologies of LSCs used in a direct clinical application. Our data show that p63-positive CK3-negative LSCs grown in vitro for clinical purposes undergo mitotic processes with extremely high fidelity, suggesting high karyotype stability. This finding confirms LSCs as a high-quality and safe therapy for eye regeneration in humans.
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Affiliation(s)
- Marija Zekušić
- Department of Transfusion and Regenerative Medicine, Sestre milosrdnice University Hospital Center, Zagreb, Croatia
| | - Marina Bujić Mihica
- Department of Transfusion and Regenerative Medicine, Sestre milosrdnice University Hospital Center, Zagreb, Croatia.
| | - Marija Skoko
- Department of Transfusion and Regenerative Medicine, Sestre milosrdnice University Hospital Center, Zagreb, Croatia
| | - Kruno Vukušić
- Division of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia
| | - Patrik Risteski
- Division of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia
| | - Jelena Martinčić
- Division of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia
| | - Iva M Tolić
- Division of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia
| | - Krešo Bendelja
- Center for Research and Knowledge Transfer in Biotechnology, Laboratory of Immunology, University of Zagreb, Zagreb, Croatia
| | - Snježana Ramić
- Department of Oncological Pathology and Clinical Cytology 'Ljudevit Jurak', University Hospital Center Sestre Milosrdnice, Zagreb, Croatia
| | - Tamara Dolenec
- Department of Transfusion and Regenerative Medicine, Sestre milosrdnice University Hospital Center, Zagreb, Croatia
| | - Ivana Vrgoč Zimić
- Department of Transfusion and Regenerative Medicine, Sestre milosrdnice University Hospital Center, Zagreb, Croatia
| | - Dominik Puljić
- Department of Transfusion and Regenerative Medicine, Sestre milosrdnice University Hospital Center, Zagreb, Croatia
| | - Ivanka Petric Vicković
- Clinical Department of Ophthalmology, Sestre milosrdnice University Hospital Center, Zagreb, Croatia
| | - Renata Iveković
- Clinical Department of Ophthalmology, Sestre milosrdnice University Hospital Center, Zagreb, Croatia
| | - Ivanka Batarilo
- Department of Microbiology, Croatian Institute of Transfusion Medicine, Zagreb, Croatia
| | - Uršula Prosenc Zmrzljak
- Molecular Biology Department, BIA Separations CRO, Labena d.O.O, Ljubljana, Slovenia
- Labena d.o.o, Zagreb, Croatia
| | | | - Tiha Vučemilo
- Department of Transfusion and Regenerative Medicine, Sestre milosrdnice University Hospital Center, Zagreb, Croatia
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6
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Neahring L, He Y, Cho NH, Liu G, Fernandes J, Rux CJ, Nakos K, Subramanian R, Upadhyayula S, Yildiz A, Dumont S. Torques within and outside the human spindle balance twist at anaphase. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.10.570990. [PMID: 38405786 PMCID: PMC10888964 DOI: 10.1101/2023.12.10.570990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
At each cell division, nanometer-scale motors and microtubules give rise to the micron-scale spindle. Many mitotic motors step helically around microtubules in vitro, and most are predicted to twist the spindle in a left-handed direction. However, the human spindle exhibits only slight global twist, raising the question of how these molecular torques are balanced. Here, using lattice light sheet microscopy, we find that anaphase spindles in the epithelial cell line MCF10A have a high baseline twist, and we identify factors that both increase and decrease this twist. The midzone motors KIF4A and MKLP1 are redundantly required for left-handed twist at anaphase, and we show that KIF4A generates left-handed torque in vitro. The actin cytoskeleton also contributes to left-handed twist, but dynein and its cortical recruitment factor LGN counteract it. Together, our work demonstrates that force generators regulate twist in opposite directions from both within and outside the spindle, preventing strong spindle twist during chromosome segregation.
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Affiliation(s)
- Lila Neahring
- Department of Bioengineering & Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA
- Developmental & Stem Cell Biology Graduate Program, University of California San Francisco, San Francisco, CA, USA
| | - Yifei He
- Department of Chemistry, University of California Berkeley, Berkeley, CA, USA
| | - Nathan H. Cho
- Department of Bioengineering & Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA
- Tetrad Graduate Program, University of California San Francisco, San Francisco, CA, USA
| | - Gaoxiang Liu
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, USA
| | - Jonathan Fernandes
- Department of Chemistry, University of California Berkeley, Berkeley, CA, USA
| | - Caleb J. Rux
- Department of Bioengineering & Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA
- UC Berkeley/UC San Francisco Graduate Group in Bioengineering, Berkeley, CA, USA
| | - Konstantinos Nakos
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Radhika Subramanian
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Srigokul Upadhyayula
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Chan Zuckerberg Biohub, San Francisco, CA, USA
| | - Ahmet Yildiz
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, USA
- Physics Department, University of California Berkeley, Berkeley, CA, USA
| | - Sophie Dumont
- Department of Bioengineering & Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA
- Developmental & Stem Cell Biology Graduate Program, University of California San Francisco, San Francisco, CA, USA
- Tetrad Graduate Program, University of California San Francisco, San Francisco, CA, USA
- UC Berkeley/UC San Francisco Graduate Group in Bioengineering, Berkeley, CA, USA
- Chan Zuckerberg Biohub, San Francisco, CA, USA
- Department of Biochemistry & Biophysics, University of California San Francisco, San Francisco, CA, USA
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7
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do Rosário CF, Zhang Y, Stadnicki J, Ross JL, Wadsworth P. Lateral and longitudinal compaction of PRC1 overlap zones drives stabilization of interzonal microtubules. Mol Biol Cell 2023; 34:ar100. [PMID: 37467037 PMCID: PMC10551706 DOI: 10.1091/mbc.e23-02-0049] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 06/20/2023] [Accepted: 07/04/2023] [Indexed: 07/20/2023] Open
Abstract
During anaphase, antiparallel-overlapping midzone microtubules elongate and form bundles, contributing to chromosome segregation and the location of contractile ring formation. Midzone microtubules are dynamic in early but not late anaphase; however, the kinetics and mechanisms of stabilization are incompletely understood. Using photoactivation of cells expressing PA-EGFP-α-tubulin we find that immediately after anaphase onset, a single highly dynamic population of midzone microtubules is present; as anaphase progresses, both dynamic and stable populations of midzone microtubules coexist. By mid-cytokinesis, only static, non-dynamic microtubules are detected. The velocity of microtubule sliding also decreases as anaphase progresses, becoming undetectable by late anaphase. Following depletion of PRC1, midzone microtubules remain highly dynamic in anaphase and fail to form static arrays in telophase despite furrowing. Cells depleted of Kif4a contain elongated PRC1 overlap zones and fail to form static arrays in telophase. Cells blocked in cytokinesis form short PRC1 overlap zones that do not coalesce laterally; these cells also fail to form static arrays in telophase. Together, our results demonstrate that dynamic turnover and sliding of midzone microtubules is gradually reduced during anaphase and that the final transition to a static array in telophase requires both lateral and longitudinal compaction of PRC1 containing overlap zones.
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Affiliation(s)
- Carline Fermino do Rosário
- Department of Biology, University of Massachusetts Amherst, Amherst MA 01003
- Program in Molecular and Cellular Biology, University of Massachusetts Amherst, Amherst MA 01003
| | - Ying Zhang
- Department of Biology, University of Massachusetts Amherst, Amherst MA 01003
| | - Jennifer Stadnicki
- Department of Biology, University of Massachusetts Amherst, Amherst MA 01003
- Program in Molecular and Cellular Biology, University of Massachusetts Amherst, Amherst MA 01003
| | | | - Patricia Wadsworth
- Department of Biology, University of Massachusetts Amherst, Amherst MA 01003
- Program in Molecular and Cellular Biology, University of Massachusetts Amherst, Amherst MA 01003
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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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9
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Torvi JR, Wong J, Drubin DG, Barnes G. Interdependence of a microtubule polymerase and a motor protein in establishment of kinetochore end-on attachments. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.08.544255. [PMID: 37333421 PMCID: PMC10274876 DOI: 10.1101/2023.06.08.544255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Faithful segregation of chromosomes into daughter cells during mitosis requires formation of attachments between kinetochores and mitotic spindle microtubules. Chromosome alignment on the mitotic spindle, also referred to as congression, is facilitated by translocation of side-bound chromosomes along the microtubule surface, which allows the establishment of end-on attachment of kinetochores to microtubule plus ends. Spatial and temporal constraints hinder observation of these events in live cells. Therefore, we used our previously developed reconstitution assay to observe dynamics of kinetochores, the yeast kinesin-8, Kip3, and the microtubule polymerase, Stu2, in lysates prepared from metaphase-arrested budding yeast, Saccharomyces cerevisiae . Using total internal reflection fluorescence (TIRF) microscopy to observe kinetochore translocation on the lateral microtubule surface toward the microtubule plus end, motility was shown to be dependent on both Kip3, as we reported previously, and Stu2. These proteins were shown to have distinct dynamics on the microtubule. Kip3 is highly processive and moves faster than the kinetochore. Stu2 tracks both growing and shrinking microtubule ends but also colocalizes with moving lattice-bound kinetochores. In cells, we observed that both Kip3 and Stu2 are important for establishing chromosome biorientation, Moreover, when both proteins are absent, biorientation is completely defective. All cells lacking both Kip3 and Stu2 had declustered kinetochores and about half also had at least one unattached kinetochore. Our evidence argues that despite differences in their dynamics, Kip3 and Stu2 share roles in chromosome congression to facilitate proper kinetochore-microtubule attachment.
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10
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Matković J, Ghosh S, Ćosić M, Eibes S, Barišić M, Pavin N, Tolić IM. Kinetochore- and chromosome-driven transition of microtubules into bundles promotes spindle assembly. Nat Commun 2022; 13:7307. [PMID: 36435852 PMCID: PMC9701229 DOI: 10.1038/s41467-022-34957-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 11/11/2022] [Indexed: 11/28/2022] Open
Abstract
Mitotic spindle assembly is crucial for chromosome segregation and relies on bundles of microtubules that extend from the poles and overlap in the middle. However, how these structures form remains poorly understood. Here we show that overlap bundles arise through a network-to-bundles transition driven by kinetochores and chromosomes. STED super-resolution microscopy reveals that PRC1-crosslinked microtubules initially form loose arrays, which become rearranged into bundles. Kinetochores promote microtubule bundling by lateral binding via CENP-E/kinesin-7 in an Aurora B-regulated manner. Steric interactions between the bundle-associated chromosomes at the spindle midplane drive bundle separation and spindle widening. In agreement with experiments, theoretical modeling suggests that bundles arise through competing attractive and repulsive mechanisms. Finally, perturbation of overlap bundles leads to inefficient correction of erroneous kinetochore-microtubule attachments. Thus, kinetochores and chromosomes drive coarsening of a uniform microtubule array into overlap bundles, which promote not only spindle formation but also chromosome segregation fidelity.
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Affiliation(s)
- Jurica Matković
- grid.4905.80000 0004 0635 7705Division of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia
| | - Subhadip Ghosh
- grid.4808.40000 0001 0657 4636Department of Physics, Faculty of Science, University of Zagreb, Zagreb, Croatia
| | - Mateja Ćosić
- grid.4905.80000 0004 0635 7705Division of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia
| | - Susana Eibes
- grid.417390.80000 0001 2175 6024Cell Division and Cytoskeleton, Danish Cancer Society Research Center, Copenhagen, Denmark
| | - Marin Barišić
- grid.417390.80000 0001 2175 6024Cell Division and Cytoskeleton, Danish Cancer Society Research Center, Copenhagen, Denmark ,grid.5254.60000 0001 0674 042XDepartment of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Nenad Pavin
- grid.4808.40000 0001 0657 4636Department of Physics, Faculty of Science, University of Zagreb, Zagreb, Croatia
| | - Iva M. Tolić
- grid.4905.80000 0004 0635 7705Division of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia
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Suresh P, Galstyan V, Phillips R, Dumont S. Modeling and mechanical perturbations reveal how spatially regulated anchorage gives rise to spatially distinct mechanics across the mammalian spindle. eLife 2022; 11:e79558. [PMID: 36346735 PMCID: PMC9642996 DOI: 10.7554/elife.79558] [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: 04/26/2022] [Accepted: 10/12/2022] [Indexed: 11/09/2022] Open
Abstract
During cell division, the spindle generates force to move chromosomes. In mammals, microtubule bundles called kinetochore-fibers (k-fibers) attach to and segregate chromosomes. To do so, k-fibers must be robustly anchored to the dynamic spindle. We previously developed microneedle manipulation to mechanically challenge k-fiber anchorage, and observed spatially distinct response features revealing the presence of heterogeneous anchorage (Suresh et al., 2020). How anchorage is precisely spatially regulated, and what forces are necessary and sufficient to recapitulate the k-fiber's response to force remain unclear. Here, we develop a coarse-grained k-fiber model and combine with manipulation experiments to infer underlying anchorage using shape analysis. By systematically testing different anchorage schemes, we find that forces solely at k-fiber ends are sufficient to recapitulate unmanipulated k-fiber shapes, but not manipulated ones for which lateral anchorage over a 3 μm length scale near chromosomes is also essential. Such anchorage robustly preserves k-fiber orientation near chromosomes while allowing pivoting around poles. Anchorage over a shorter length scale cannot robustly restrict pivoting near chromosomes, while anchorage throughout the spindle obstructs pivoting at poles. Together, this work reveals how spatially regulated anchorage gives rise to spatially distinct mechanics in the mammalian spindle, which we propose are key for function.
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Affiliation(s)
- Pooja Suresh
- Biophysics Graduate Program, University of California, San FranciscoSan FranciscoUnited States
- Department of Bioengineering and Therapeutic Sciences, University of California, San FranciscoSan FranciscoUnited States
| | - Vahe Galstyan
- Biochemistry and Molecular Biophysics Option, California Institute of TechnologyPasadenaUnited States
- A. Alikhanyan National Laboratory (Yerevan Physics Institute)YerevanArmenia
| | - Rob Phillips
- Division of Biology and Biological Engineering, California Institute of TechnologyPasadenaUnited States
- Department of Physics, California Institute of TechnologyPasadenaUnited States
- Chan Zuckerberg Biohub, San FranciscoSan FranciscoUnited States
| | - Sophie Dumont
- Biophysics Graduate Program, University of California, San FranciscoSan FranciscoUnited States
- Department of Bioengineering and Therapeutic Sciences, University of California, San FranciscoSan FranciscoUnited States
- Chan Zuckerberg Biohub, San FranciscoSan FranciscoUnited States
- Department of Biochemistry and Biophysics, University of California, San FranciscoSan FranciscoUnited States
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