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Anjur-Dietrich MI, Gomez Hererra V, Farhadifar R, Wu H, Merta H, Bahmanyar S, Shelley MJ, Needleman DJ. Mechanics of spindle orientation in human mitotic cells is determined by pulling forces on astral microtubules and clustering of cortical dynein. Dev Cell 2024:S1534-5807(24)00340-X. [PMID: 38866013 DOI: 10.1016/j.devcel.2024.05.022] [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: 08/28/2023] [Revised: 04/03/2024] [Accepted: 05/17/2024] [Indexed: 06/14/2024]
Abstract
The forces that orient the spindle in human cells remain poorly understood due to a lack of direct mechanical measurements in mammalian systems. We use magnetic tweezers to measure the force on human mitotic spindles. Combining the spindle's measured resistance to rotation, the speed at which it rotates after laser ablating astral microtubules, and estimates of the number of ablated microtubules reveals that each microtubule contacting the cell cortex is subject to ∼5 pN of pulling force, suggesting that each is pulled on by an individual dynein motor. We find that the concentration of dynein at the cell cortex and extent of dynein clustering are key determinants of the spindle's resistance to rotation, with little contribution from cytoplasmic viscosity, which we explain using a biophysically based mathematical model. This work reveals how pulling forces on astral microtubules determine the mechanics of spindle orientation and demonstrates the central role of cortical dynein clustering.
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Affiliation(s)
- Maya I Anjur-Dietrich
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA.
| | - Vicente Gomez Hererra
- Courant Institute of Mathematical Sciences, New York University, New York, NY 10012, USA
| | - Reza Farhadifar
- Center for Computational Biology, Flatiron Institute, New York, NY 10010, USA
| | - Haiyin Wu
- Department of Physics, Harvard University, Cambridge, MA 02138, USA; Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | - Holly Merta
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06520, USA
| | - Shirin Bahmanyar
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06520, USA
| | - Michael J Shelley
- Courant Institute of Mathematical Sciences, New York University, New York, NY 10012, USA; Center for Computational Biology, Flatiron Institute, New York, NY 10010, USA
| | - Daniel J Needleman
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA; Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA; Center for Computational Biology, Flatiron Institute, New York, NY 10010, USA
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Anjur-Dietrich MI, Hererra VG, Farhadifar R, Wu H, Merta H, Bahmanyar S, Shelley MJ, Needleman DJ. Clustering of cortical dynein regulates the mechanics of spindle orientation in human mitotic cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.11.557210. [PMID: 37745442 PMCID: PMC10515834 DOI: 10.1101/2023.09.11.557210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
The forces which orient the spindle in human cells remain poorly understood due to a lack of direct mechanical measurements in mammalian systems. We use magnetic tweezers to measure the force on human mitotic spindles. Combining the spindle's measured resistance to rotation, the speed it rotates after laser ablating astral microtubules, and estimates of the number of ablated microtubules reveals that each microtubule contacting the cell cortex is subject to ~1 pN of pulling force, suggesting that each is pulled on by an individual dynein motor. We find that the concentration of dynein at the cell cortex and extent of dynein clustering are key determinants of the spindle's resistance to rotation, with little contribution from cytoplasmic viscosity, which we explain using a biophysically based mathematical model. This work reveals how pulling forces on astral microtubules determine the mechanics of spindle orientation and demonstrates the central role of cortical dynein clustering.
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Affiliation(s)
- Maya I. Anjur-Dietrich
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
| | - Vicente Gomez Hererra
- Courant Institute of Mathematical Sciences, New York University, New York, NY 10012, USA
| | - Reza Farhadifar
- Center for Computational Biology, Flatiron Institute, New York, NY 10010, USA
| | - Haiyin Wu
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | - Holly Merta
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06520, USA
| | - Shirin Bahmanyar
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06520, USA
| | - Michael J. Shelley
- Courant Institute of Mathematical Sciences, New York University, New York, NY 10012, USA
- Center for Computational Biology, Flatiron Institute, New York, NY 10010, USA
| | - Daniel J. Needleman
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
- Center for Computational Biology, Flatiron Institute, New York, NY 10010, USA
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Hernández-Sánchez F, Peraza-Reyes L. Spatiotemporal Dynamic Regulation of Organelles During Meiotic Development, Insights From Fungi. Front Cell Dev Biol 2022; 10:886710. [PMID: 35547805 PMCID: PMC9081346 DOI: 10.3389/fcell.2022.886710] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 04/08/2022] [Indexed: 12/02/2022] Open
Abstract
Eukaryotic cell development involves precise regulation of organelle activity and dynamics, which adapt the cell architecture and metabolism to the changing developmental requirements. Research in various fungal model organisms has disclosed that meiotic development involves precise spatiotemporal regulation of the formation and dynamics of distinct intracellular membrane compartments, including peroxisomes, mitochondria and distinct domains of the endoplasmic reticulum, comprising its peripheral domains and the nuclear envelope. This developmental regulation implicates changes in the constitution and dynamics of these organelles, which modulate their structure, abundance and distribution. Furthermore, selective degradation systems allow timely organelle removal at defined meiotic stages, and regulated interactions between membrane compartments support meiotic-regulated organelle dynamics. This dynamic organelle remodeling is implicated in conducting organelle segregation during meiotic differentiation, and defines quality control regulatory systems safeguarding the inheritance of functional membrane compartments, promoting meiotic cell rejuvenation. Moreover, organelle remodeling is important for proper activity of the cytoskeletal system conducting meiotic nucleus segregation, as well as for meiotic differentiation. The orchestrated regulation of organelle dynamics has a determinant contribution in the formation of the renewed genetically-diverse offspring of meiosis.
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Ecklund KH, Bailey ME, Kossen KA, Dietvorst CK, Asbury CL, Markus SM. The microtubule-associated protein She1 coordinates directional spindle positioning by spatially restricting dynein activity. J Cell Sci 2021; 134:273583. [PMID: 34854468 DOI: 10.1242/jcs.258510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 10/27/2021] [Indexed: 11/20/2022] Open
Abstract
Dynein motors move the mitotic spindle to the cell division plane in many cell types, including in budding yeast, in which dynein is assisted by numerous factors including the microtubule-associated protein (MAP) She1. Evidence suggests that She1 plays a role in polarizing dynein-mediated spindle movements toward the daughter cell; however, how She1 performs this function is unknown. We find that She1 assists dynein in maintaining the spindle in close proximity to the bud neck, such that, at anaphase onset, the chromosomes are segregated to mother and daughter cells. She1 does so by attenuating the initiation of dynein-mediated spindle movements within the mother cell, thus ensuring such movements are polarized toward the daughter cell. Our data indicate that this activity relies on She1 binding to the microtubule-bound conformation of the dynein microtubule-binding domain, and to astral microtubules within mother cells. Our findings reveal how an asymmetrically localized MAP directionally tunes dynein activity by attenuating motor activity in a spatially confined manner.
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Affiliation(s)
- Kari H Ecklund
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523, USA
| | - Megan E Bailey
- Department of Physiology and Biophysics, University of Washington, Seattle, Washington 98195, USA
| | - Kelly A Kossen
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523, USA
| | - Carsten K Dietvorst
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523, USA
| | - Charles L Asbury
- Department of Physiology and Biophysics, University of Washington, Seattle, Washington 98195, USA
| | - Steven M Markus
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523, USA
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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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Tsuchiya K, Hayashi H, Nishina M, Okumura M, Sato Y, Kanemaki MT, Goshima G, Kiyomitsu T. Ran-GTP Is Non-essential to Activate NuMA for Mitotic Spindle-Pole Focusing but Dynamically Polarizes HURP Near Chromosomes. Curr Biol 2021; 31:115-127.e3. [DOI: 10.1016/j.cub.2020.09.091] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 08/25/2020] [Accepted: 09/30/2020] [Indexed: 12/27/2022]
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Omer S, Brock K, Beckford J, Lee WL. Overexpression of Mdm36 reveals Num1 foci that mediate dynein-dependent microtubule sliding in budding yeast. J Cell Sci 2020; 133:jcs246363. [PMID: 32938686 PMCID: PMC7578358 DOI: 10.1242/jcs.246363] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 09/01/2020] [Indexed: 01/21/2023] Open
Abstract
The current model for spindle positioning requires attachment of the microtubule (MT) motor cytoplasmic dynein to the cell cortex, where it generates pulling force on astral MTs to effect spindle displacement. How dynein is anchored by cortical attachment machinery to generate large spindle-pulling forces remains unclear. Here, we show that cortical clustering of Num1, the yeast dynein attachment molecule, is limited by its assembly factor Mdm36. Overexpression of Mdm36 results in an overall enhancement of Num1 clustering but reveals a population of dim Num1 clusters that mediate dynein anchoring at the cell cortex. Direct imaging shows that bud-localized, dim Num1 clusters containing around only six Num1 molecules mediate dynein-dependent spindle pulling via a lateral MT sliding mechanism. Mutations affecting Num1 clustering interfere with mitochondrial tethering but do not interfere with the dynein-based spindle-pulling function of Num1. We propose that formation of small ensembles of attachment molecules is sufficient for dynein anchorage and cortical generation of large spindle-pulling forces.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Safia Omer
- Department of Biological Sciences, Dartmouth College, 78 College Street, Hanover, NH 03755, USA
| | - Katia Brock
- Department of Biological Sciences, Dartmouth College, 78 College Street, Hanover, NH 03755, USA
| | - John Beckford
- Department of Biological Sciences, Dartmouth College, 78 College Street, Hanover, NH 03755, USA
| | - Wei-Lih Lee
- Department of Biological Sciences, Dartmouth College, 78 College Street, Hanover, NH 03755, USA
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Torii T, Ogawa Y, Liu CH, Ho TSY, Hamdan H, Wang CC, Oses-Prieto JA, Burlingame AL, Rasband MN. NuMA1 promotes axon initial segment assembly through inhibition of endocytosis. J Cell Biol 2020; 219:jcb.201907048. [PMID: 31727776 PMCID: PMC7041696 DOI: 10.1083/jcb.201907048] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 10/17/2019] [Accepted: 11/01/2019] [Indexed: 11/22/2022] Open
Abstract
Axon initial segments (AISs) initiate action potentials and regulate the trafficking of vesicles between somatodendritic and axonal compartments. Torii et al. show that NuMA1 is transiently located at the AIS and promotes rapid AIS assembly by inhibiting the endocytosis of neurofascin-186. Axon initial segments (AISs) initiate action potentials and regulate the trafficking of vesicles between somatodendritic and axonal compartments. However, the mechanisms controlling AIS assembly remain poorly defined. We performed differential proteomics and found nuclear mitotic apparatus protein 1 (NuMA1) is downregulated in AIS-deficient neonatal mouse brains and neurons. NuMA1 is transiently located at the AIS during development where it interacts with the scaffolding protein 4.1B and the dynein regulator lissencephaly 1 (Lis1). Silencing NuMA1 or protein 4.1B by shRNA disrupts AIS assembly, but not maintenance. Silencing Lis1 or overexpressing NuMA1 during AIS assembly increased the density of AIS proteins, including ankyrinG and neurofascin-186 (NF186). NuMA1 inhibits the endocytosis of AIS NF186 by impeding Lis1’s interaction with doublecortin, a potent facilitator of NF186 endocytosis. Our results indicate the transient expression and AIS localization of NuMA1 stabilizes the developing AIS by inhibiting endocytosis and removal of AIS proteins.
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Affiliation(s)
- Tomohiro Torii
- Department of Neuroscience, Baylor College of Medicine, Houston, TX
| | - Yuki Ogawa
- Department of Neuroscience, Baylor College of Medicine, Houston, TX
| | - Cheng-Hsin Liu
- Department of Neuroscience, Baylor College of Medicine, Houston, TX
| | - Tammy Szu-Yu Ho
- Department of Neuroscience, Baylor College of Medicine, Houston, TX
| | - Hamdan Hamdan
- Department of Neuroscience, Baylor College of Medicine, Houston, TX
| | - Chih-Chuan Wang
- Department of Neuroscience, Baylor College of Medicine, Houston, TX
| | - Juan A Oses-Prieto
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA
| | - Alma L Burlingame
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA
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Kiyomitsu T. The cortical force-generating machinery: how cortical spindle-pulling forces are generated. Curr Opin Cell Biol 2019; 60:1-8. [PMID: 30954860 DOI: 10.1016/j.ceb.2019.03.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 02/24/2019] [Accepted: 03/03/2019] [Indexed: 12/12/2022]
Abstract
The cortical force-generating machinery pulls on dynamic plus-ends of astral microtubules to control spindle position and orientation, which underlie division type specification and cellular patterning in many eukaryotic cells. A prior work identified cytoplasmic dynein, a minus-end directed microtubule motor, as a key conserved unit of the cortical force-generating machinery. Here, I summarize recent structural, biophysical, and cell-biological studies that advance our understanding of how dynein is activated and organized at the mitotic cell cortex to generate functional spindle-pulling forces. In addition, I introduce recent findings of dynein-independent or parallel mechanisms for achieving oriented cell division.
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Affiliation(s)
- Tomomi Kiyomitsu
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan.
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Abstract
For over a century, the centrosome has been an organelle more easily tracked than understood, and the study of its peregrinations within the cell remains a chief underpinning of its functional investigation. Increasing attention and new approaches have been brought to bear on mechanisms that control centrosome localization in the context of cleavage plane determination, ciliogenesis, directional migration, and immunological synapse formation, among other cellular and developmental processes. The Golgi complex, often linked with the centrosome, presents a contrasting case of a pleiomorphic organelle for which functional studies advanced somewhat more rapidly than positional tracking. However, Golgi orientation and distribution has emerged as an area of considerable interest with respect to polarized cellular function. This chapter will review our current understanding of the mechanism and significance of the positioning of these organelles.
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