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Langner E, Puapatanakul P, Pudlowski R, Alsabbagh DY, Miner JH, Horani A, Dutcher SK, Brody SL, Wang JT, Suleiman HY, Mahjoub MR. Ultrastructure expansion microscopy (U-ExM) of mouse and human kidneys for analysis of subcellular structures. Cytoskeleton (Hoboken) 2024. [PMID: 38715433 DOI: 10.1002/cm.21870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Revised: 04/11/2024] [Accepted: 04/22/2024] [Indexed: 05/21/2024]
Abstract
Ultrastructure expansion microscopy (U-ExM) involves the physical magnification of specimens embedded in hydrogels, which allows for super-resolution imaging of subcellular structures using a conventional diffraction-limited microscope. Methods for expansion microscopy exist for several organisms, organs, and cell types, and used to analyze cellular organelles and substructures in nanoscale resolution. Here, we describe a simple step-by-step U-ExM protocol for the expansion, immunostaining, imaging, and analysis of cytoskeletal and organellar structures in kidney tissue. We detail the critical modified steps to optimize isotropic kidney tissue expansion, and preservation of the renal cell structures of interest. We demonstrate the utility of the approach using several markers of renal cell types, centrioles, cilia, the extracellular matrix, and other cytoskeletal elements. Finally, we show that the approach works well on mouse and human kidney samples that were preserved using different fixation and embedding conditions. Overall, this protocol provides a simple and cost-effective approach to analyze both preclinical and clinical renal samples in high detail, using conventional lab supplies and standard widefield or confocal microscopy.
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Affiliation(s)
- Ewa Langner
- Department of Medicine, Washington University, St. Louis, Missouri, USA
| | - Pongpratch Puapatanakul
- Department of Medicine, Washington University, St. Louis, Missouri, USA
- Division of Nephrology, Department of Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Rachel Pudlowski
- Department of Biology, Washington University, St. Louis, Missouri, USA
| | | | - Jeffrey H Miner
- Department of Medicine, Washington University, St. Louis, Missouri, USA
| | - Amjad Horani
- Department of Pediatrics, Washington University, St. Louis, Missouri, USA
| | - Susan K Dutcher
- Department of Genetics, Washington University, St. Louis, Missouri, USA
| | - Steven L Brody
- Department of Medicine, Washington University, St. Louis, Missouri, USA
| | - Jennifer T Wang
- Division of Nephrology, Department of Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Hani Y Suleiman
- Department of Medicine, Washington University, St. Louis, Missouri, USA
| | - Moe R Mahjoub
- Department of Medicine, Washington University, St. Louis, Missouri, USA
- Department of Cell Biology and Physiology, Washington University, St. Louis, Missouri, USA
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2
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Langner E, Puapatanakul P, Pudlowski R, Alsabbagh DY, Miner JH, Horani A, Dutcher SK, Brody SL, Wang JT, Suleiman HY, Mahjoub MR. Ultrastructure expansion microscopy (U-ExM) of mouse and human kidneys for analysis of subcellular structures. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.16.580708. [PMID: 38405695 PMCID: PMC10889020 DOI: 10.1101/2024.02.16.580708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Ultrastructure expansion microscopy (U-ExM) involves the physical magnification of specimens embedded in hydrogels, which allows for super-resolution imaging of subcellular structures using a conventional diffraction-limited microscope. Methods for expansion microscopy exist for several organisms, organs, and cell types, and used to analyze cellular organelles and substructures in nanoscale resolution. Here, we describe a simple step-by-step U-ExM protocol for the expansion, immunostaining, imaging, and analysis of cytoskeletal and organellar structures in kidney tissue. We detail the critical modified steps to optimize isotropic kidney tissue expansion, and preservation of the renal cell structures of interest. We demonstrate the utility of the approach using several markers of renal cell types, centrioles, cilia, the extracellular matrix, and other cytoskeletal elements. Finally, we show that the approach works well on mouse and human kidney samples that were preserved using different fixation and storage conditions. Overall, this protocol provides a simple and cost-effective approach to analyze both pre-clinical and clinical renal samples in high detail, using conventional lab supplies and standard widefield or confocal microscopy.
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3
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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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4
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Zeeshan M, Rea E, Abel S, Vukušić K, Markus R, Brady D, Eze A, Rashpa R, Balestra AC, Bottrill AR, Brochet M, Guttery DS, Tolić IM, Holder AA, Le Roch KG, Tromer EC, Tewari R. Plasmodium ARK2 and EB1 drive unconventional spindle dynamics, during chromosome segregation in sexual transmission stages. Nat Commun 2023; 14:5652. [PMID: 37704606 PMCID: PMC10499817 DOI: 10.1038/s41467-023-41395-3] [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: 02/01/2023] [Accepted: 08/30/2023] [Indexed: 09/15/2023] Open
Abstract
The Aurora family of kinases orchestrates chromosome segregation and cytokinesis during cell division, with precise spatiotemporal regulation of its catalytic activities by distinct protein scaffolds. Plasmodium spp., the causative agents of malaria, are unicellular eukaryotes with three unique and highly divergent aurora-related kinases (ARK1-3) that are essential for asexual cellular proliferation but lack most canonical scaffolds/activators. Here we investigate the role of ARK2 during sexual proliferation of the rodent malaria Plasmodium berghei, using a combination of super-resolution microscopy, mass spectrometry, and live-cell fluorescence imaging. We find that ARK2 is primarily located at spindle microtubules in the vicinity of kinetochores during both mitosis and meiosis. Interactomic and co-localisation studies reveal several putative ARK2-associated interactors including the microtubule-interacting protein EB1, together with MISFIT and Myosin-K, but no conserved eukaryotic scaffold proteins. Gene function studies indicate that ARK2 and EB1 are complementary in driving endomitotic division and thereby parasite transmission through the mosquito. This discovery underlines the flexibility of molecular networks to rewire and drive unconventional mechanisms of chromosome segregation in the malaria parasite.
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Affiliation(s)
- Mohammad Zeeshan
- School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Edward Rea
- School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Steven Abel
- Department of Molecular, Cell and Systems Biology, University of California Riverside, 900 University Ave., Riverside, CA, USA
| | - Kruno Vukušić
- Division of Molecular Biology, Ruđer Bošković Institute, 10000, Zagreb, Croatia
| | - Robert Markus
- School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Declan Brady
- School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Antonius Eze
- School of Life Sciences, University of Nottingham, Nottingham, UK
- Department of Medical Biochemistry, Faculty of Basic Medical Sciences, College of Medicine, University of Nigeria, Enugu Campus, Enugu, Nigeria
| | - Ravish Rashpa
- Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | | | - Andrew R Bottrill
- School of Life Sciences, Gibbet Hill Campus, University of Warwick, Coventry, UK
| | - Mathieu Brochet
- Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - David S Guttery
- Department of Genetics and Genome Biology, College of Life Sciences, University of Leicester, Leicester, UK
| | - Iva M Tolić
- Division of Molecular Biology, Ruđer Bošković Institute, 10000, Zagreb, Croatia
| | - Anthony A Holder
- Malaria Parasitology Laboratory, The Francis Crick Institute, London, UK
| | - Karine G Le Roch
- Department of Molecular, Cell and Systems Biology, University of California Riverside, 900 University Ave., Riverside, CA, USA
| | - Eelco C Tromer
- Cell Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, Faculty of Science and Engineering, University of Groningen, Groningen, The Netherlands
| | - Rita Tewari
- School of Life Sciences, University of Nottingham, Nottingham, UK.
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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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6
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Wu H, Wang LS, Li P, Yu J, Cheng S, Yu G, Ahmad M, Meng XL, Luo H, Xu BX. Discovery of novel N-aryl-2-trifluoromethyl-quinazoline-4-amine derivatives as the inhibitors of tubulin polymerization in leukemia cells. Eur J Med Chem 2023; 256:115470. [PMID: 37201429 DOI: 10.1016/j.ejmech.2023.115470] [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: 04/20/2023] [Revised: 05/05/2023] [Accepted: 05/05/2023] [Indexed: 05/20/2023]
Abstract
A series of new N-aryl-2-trifluoromethylquinazoline-4-amine analogs were designed and synthesized based on structure optimization of quinazoline by introducing a trifluoromethyl group into 2-position. The structures of the twenty-four newly synthesized compounds were confirmed by 1H NMR, 13C NMR and ESI-MS. The in vitro anti-cancer activity against chronic myeloid leukemia cells (K562), erythroleukemia cells (HEL), human prostate cancer cells (LNCaP), and cervical cancer cells (HeLa) of the target compounds was evaluated. Among them, compounds 15d, 15f, 15h, and 15i showed the significantly (P < 0.01) stronger growth inhibitory activity on K562 than those of the positive controls of paclitaxel and colchicine, while compounds 15a, 15d, 15e, and 15h displayed significantly stronger growth inhibitory activity on HEL than those of the positive controls. However, all the target compounds exhibited weaker growth inhibition activity against K562 and HeLa than those of the positive controls. The selectivity ratio of compounds 15h, 15d, and 15i were significantly higher than those of other active compounds, indicating that these three compounds had the lower hepatotoxicity. Several compounds displayed strong inhibition against leukemia cells. They inhibited tubulin polymerization, disrupted cellular microtubule networks by targeting the colchicine site, and promoted cell cycle arrest of leukemia cells at G2/M phase and cell apoptosis, as well as inhibiting angiogenesis. In summary, our research provided that novel synthesized N-aryl-2-trifluoromethyl-quinazoline-4-amine active derivatives as the inhibitors of tubulin polymerization in leukemia cells, which might be a valuable lead compounds for anti-leukemia agents.
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Affiliation(s)
- Hui Wu
- State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang, 550014, China; The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academy of Sciences, Guiyang, 550014, China; School of Pharmaceutical Sciences, Guizhou Medical University, Guiyang, 550025, China
| | - Long-Shan Wang
- State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang, 550014, China; The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academy of Sciences, Guiyang, 550014, China; School of Pharmaceutical Sciences, Guizhou Medical University, Guiyang, 550025, China
| | - Pei Li
- State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang, 550014, China; The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academy of Sciences, Guiyang, 550014, China
| | - Jia Yu
- State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang, 550014, China; The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academy of Sciences, Guiyang, 550014, China
| | - Sha Cheng
- State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang, 550014, China; The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academy of Sciences, Guiyang, 550014, China
| | - Gang Yu
- State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang, 550014, China; The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academy of Sciences, Guiyang, 550014, China
| | - Mashaal Ahmad
- State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang, 550014, China; The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academy of Sciences, Guiyang, 550014, China
| | - Xue-Ling Meng
- State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang, 550014, China; The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academy of Sciences, Guiyang, 550014, China
| | - Heng Luo
- State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang, 550014, China; The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academy of Sciences, Guiyang, 550014, China.
| | - Bi-Xue Xu
- State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang, 550014, China; The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academy of Sciences, Guiyang, 550014, China.
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7
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Zeeshan M, Rea E, Abel S, Vukušić K, Markus R, Brady D, Eze A, Raspa R, Balestra A, Bottrill AR, Brochet M, Guttery DS, Tolić IM, Holder AA, Roch KGL, Tromer EC, Tewari R. Plasmodium ARK2-EB1 axis drives the unconventional spindle dynamics, scaffold formation and chromosome segregation of sexual transmission stages. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.29.526106. [PMID: 36778504 PMCID: PMC9915484 DOI: 10.1101/2023.01.29.526106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Mechanisms of cell division are remarkably diverse, suggesting the underlying molecular networks among eukaryotes differ extensively. The Aurora family of kinases orchestrates the process of chromosome segregation and cytokinesis during cell division through precise spatiotemporal regulation of their catalytic activities by distinct scaffolds. Plasmodium spp., the causative agents of malaria, are unicellular eukaryotes that have three divergent aurora-related kinases (ARKs) and lack most canonical scaffolds/activators. The parasite uses unconventional modes of chromosome segregation during endomitosis and meiosis in sexual transmission stages within mosquito host. This includes a rapid threefold genome replication from 1N to 8N with successive cycles of closed mitosis, spindle formation and chromosome segregation within eight minutes (termed male gametogony). Kinome studies had previously suggested likely essential functions for all three Plasmodium ARKs during asexual mitotic cycles; however, little is known about their location, function, or their scaffolding molecules during unconventional sexual proliferative stages. Using a combination of super-resolution microscopy, mass spectrometry, and live-cell fluorescence imaging, we set out to investigate the role of the atypical Aurora paralog ARK2 to proliferative sexual stages using rodent malaria model Plasmodium berghei . We find that ARK2 primarily localises to the spindle apparatus in the vicinity of kinetochores during both mitosis and meiosis. Interactomics and co-localisation studies reveal a unique ARK2 scaffold at the spindle including the microtubule plus end-binding protein EB1, lacking conserved Aurora scaffold proteins. Gene function studies indicate complementary functions of ARK2 and EB1 in driving endomitotic divisions and thereby parasite transmission. Our discovery of a novel Aurora kinase spindle scaffold underlines the emerging flexibility of molecular networks to rewire and drive unconventional mechanisms of chromosome segregation in the malaria parasite Plasmodium .
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8
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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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9
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Laporte MH, Klena N, Hamel V, Guichard P. Visualizing the native cellular organization by coupling cryofixation with expansion microscopy (Cryo-ExM). Nat Methods 2022; 19:216-222. [PMID: 35027766 PMCID: PMC8828483 DOI: 10.1038/s41592-021-01356-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 11/17/2021] [Indexed: 12/11/2022]
Abstract
Cryofixation has proven to be the gold standard for efficient preservation of native cell ultrastructure compared to chemical fixation, but this approach is not widely used in fluorescence microscopy owing to implementation challenges. Here, we develop Cryo-ExM, a method that preserves native cellular organization by coupling cryofixation with expansion microscopy. This method bypasses artifacts associated with chemical fixation and its simplicity will contribute to its widespread use in super-resolution microscopy.
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Affiliation(s)
- Marine H Laporte
- Department of Cell Biology, University of Geneva, Geneva, Switzerland
| | - Nikolai Klena
- Department of Cell Biology, University of Geneva, Geneva, Switzerland
| | - Virginie Hamel
- Department of Cell Biology, University of Geneva, Geneva, Switzerland.
| | - Paul Guichard
- Department of Cell Biology, University of Geneva, Geneva, Switzerland.
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10
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Bolanos-Garcia VM. On the Regulation of Mitosis by the Kinetochore, a Macromolecular Complex and Organising Hub of Eukaryotic Organisms. Subcell Biochem 2022; 99:235-267. [PMID: 36151378 DOI: 10.1007/978-3-031-00793-4_7] [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] [Indexed: 06/16/2023]
Abstract
The kinetochore is the multiprotein complex of eukaryotic organisms that is assembled on mitotic or meiotic centromeres to connect centromeric DNA with microtubules. Its function involves the coordinated action of more than 100 different proteins. The kinetochore acts as an organiser hub that establishes physical connections with microtubules and centromere-associated proteins and recruits central protein components of the spindle assembly checkpoint (SAC), an evolutionarily conserved surveillance mechanism of eukaryotic organisms that detects unattached kinetochores and destabilises incorrect kinetochore-microtubule attachments. The molecular communication between the kinetochore and the SAC is highly dynamic and tightly regulated to ensure that cells can progress towards anaphase until each chromosome is properly bi-oriented on the mitotic spindle. This is achieved through an interplay of highly cooperative interactions and concerted phosphorylation/dephosphorylation events that are organised in time and space.This contribution discusses our current understanding of the function, structure and regulation of the kinetochore, in particular, how its communication with the SAC results in the amplification of specific signals to exquisitely control the eukaryotic cell cycle. This contribution also addresses recent advances in machine learning approaches, cell imaging and proteomics techniques that have enhanced our understanding of the molecular mechanisms that ensure the high fidelity and timely segregation of the genetic material every time a cell divides as well as the current challenges in the study of this fascinating molecular machine.
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Affiliation(s)
- Victor M Bolanos-Garcia
- Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, UK.
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11
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Vukušić K, Ponjavić I, Buđa R, Risteski P, Tolić IM. Microtubule-sliding modules based on kinesins EG5 and PRC1-dependent KIF4A drive human spindle elongation. Dev Cell 2021; 56:1253-1267.e10. [PMID: 33910056 PMCID: PMC8098747 DOI: 10.1016/j.devcel.2021.04.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 01/03/2021] [Accepted: 04/05/2021] [Indexed: 12/13/2022]
Abstract
Proper chromosome segregation into two future daughter cells requires the mitotic spindle to elongate in anaphase. However, although some candidate proteins are implicated in this process, the molecular mechanism that drives spindle elongation in human cells is unknown. Using combined depletion and inactivation assays together with CRISPR technology to explore redundancy between multiple targets, we discovered that the force-generating mechanism of spindle elongation consists of EG5/kinesin-5 together with the PRC1-dependent motor KIF4A/kinesin-4, with contribution from kinesin-6 and kinesin-8. Disruption of EG5 and KIF4A leads to total failure of chromosome segregation due to blocked spindle elongation, despite poleward chromosome motion. Tubulin photoactivation, stimulated emission depletion (STED), and expansion microscopy show that perturbation of both proteins impairs midzone microtubule sliding without affecting microtubule stability. Thus, two mechanistically distinct sliding modules, one based on a self-sustained and the other on a crosslinker-assisted motor, power the mechanism that drives spindle elongation in human cells.
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Affiliation(s)
- Kruno Vukušić
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia
| | - Ivana Ponjavić
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia
| | - Renata Buđa
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia
| | - Patrik Risteski
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia
| | - Iva M Tolić
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia.
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