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Cantwell H, Dey G. Nuclear size and shape control. Semin Cell Dev Biol 2021; 130:90-97. [PMID: 34776332 DOI: 10.1016/j.semcdb.2021.10.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 10/26/2021] [Accepted: 10/29/2021] [Indexed: 11/27/2022]
Abstract
The nucleus displays a wide range of sizes and shapes in different species and cell types, yet its size scaling and many of the key structural constituents that determine its shape are highly conserved. In this review, we discuss the cellular properties and processes that contribute to nuclear size and shape control, drawing examples from across eukaryotes and highlighting conserved themes and pathways. We then outline physiological roles that have been uncovered for specific nuclear morphologies and disease pathologies associated with aberrant nuclear morphology. We argue that a comparative approach, assessing and integrating observations from different systems, will be a powerful way to help us address the open questions surrounding functional roles of nuclear size and shape in cell physiology.
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Affiliation(s)
- Helena Cantwell
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA 94720, USA.
| | - Gautam Dey
- Cell Biology and Biophysics, European Molecular Biology Laboratory, Meyerhofstr.1, 69117 Heidelberg, Germany.
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Modelling Nuclear Morphology and Shape Transformation: A Review. MEMBRANES 2021; 11:membranes11070540. [PMID: 34357190 PMCID: PMC8304582 DOI: 10.3390/membranes11070540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 07/14/2021] [Accepted: 07/14/2021] [Indexed: 11/20/2022]
Abstract
As one of the most important cellular compartments, the nucleus contains genetic materials and separates them from the cytoplasm with the nuclear envelope (NE), a thin membrane that is susceptible to deformations caused by intracellular forces. Interestingly, accumulating evidence has also indicated that the morphology change of NE is tightly related to nuclear mechanotransduction and the pathogenesis of diseases such as cancer and Hutchinson–Gilford Progeria Syndrome. Theoretically, with the help of well-designed experiments, significant progress has been made in understanding the physical mechanisms behind nuclear shape transformation in different cellular processes as well as its biological implications. Here, we review different continuum-level (i.e., energy minimization, boundary integral and finite element-based) approaches that have been developed to predict the morphology and shape change of the cell nucleus. Essential gradients, relative advantages and limitations of each model will be discussed in detail, with the hope of sparking a greater research interest in this important topic in the future.
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Shao X, Sørensen MH, Xia X, Fang C, Hui TH, Chang RCC, Chu Z, Lin Y. Beading of injured axons driven by tension- and adhesion-regulated membrane shape instability. J R Soc Interface 2020; 17:20200331. [PMCID: PMC7423423 DOI: 10.1098/rsif.2020.0331] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 07/13/2020] [Indexed: 08/14/2023] Open
Abstract
The formation of multiple beads along an injured axon will lead to blockage of axonal transport and eventually neuron death, and this has been widely recognized as a hallmark of nervous system degeneration. Nevertheless, the underlying mechanisms remain poorly understood. Here, we report a combined experimental and theoretical study to reveal key factors governing axon beading. Specifically, by transecting well-developed axons with a sharp atomic force microscope probe, significant beading of the axons was triggered. We showed that adhesion was not required for beading to occur, although when present strong axon–substrate attachments seemed to set the locations for bead formation. In addition, the beading wavelength, representing the average distance between beads, was found to correlate with the size and cytoskeleton integrity of axon, with a thinner axon or a disrupted actin cytoskeleton both leading to a shorter beading wavelength. A model was also developed to explain these observations which suggest that axon beading originates from the shape instability of the membrane and is driven by the release of work done by axonal tension as well as the reduction of membrane surface energy. The beading wavelength predicted from this theory was in good agreement with our experiments under various conditions. By elucidating the essential physics behind axon beading, the current study could enhance our understanding of how axonal injury and neurodegeneration progress as well as provide insights for the development of possible treatment strategies.
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Affiliation(s)
- Xueying Shao
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, People's Republic of China
- HKU-Shenzhen Institute of Research and Innovation, Shenzhen, Guangdong, People's Republic of China
| | - Maja Højvang Sørensen
- Laboratory of Neurodegenerative Diseases, School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, People's Republic of China
| | - Xingyu Xia
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, People's Republic of China
- HKU-Shenzhen Institute of Research and Innovation, Shenzhen, Guangdong, People's Republic of China
| | - Chao Fang
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, People's Republic of China
- HKU-Shenzhen Institute of Research and Innovation, Shenzhen, Guangdong, People's Republic of China
| | - Tsz Hin Hui
- Department of Electrical and Electronic Engineering, Joint Appointment with School of Biomedical Sciences, The University of Hong Kong, Hong Kong, People's Republic of China
| | - Raymond Chuen Chung Chang
- Laboratory of Neurodegenerative Diseases, School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, People's Republic of China
| | - Zhiqin Chu
- Department of Electrical and Electronic Engineering, Joint Appointment with School of Biomedical Sciences, The University of Hong Kong, Hong Kong, People's Republic of China
| | - Yuan Lin
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, People's Republic of China
- HKU-Shenzhen Institute of Research and Innovation, Shenzhen, Guangdong, People's Republic of China
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Wu Z, Yuan H, Zhang X, Yi X. Sidewall contact regulating the nanorod packing inside vesicles with relative volumes. SOFT MATTER 2019; 15:2552-2559. [PMID: 30839980 DOI: 10.1039/c8sm01656a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Intracellular packing of one-dimensional and rodlike materials plays an important role in many biological processes such as cell mimicking, microtubule protrusion, cell division, frustrated phagocytosis, and pathogenicity. To understand the mechanical interplay between cells/intracellular membranous organelles and encapsulated rodlike materials, we perform theoretical analyses to investigate how the morphologies and mechanical behaviors of lipid vesicles of given relative volumes are regulated by encapsulated rigid nanorods of finite diameters and selected geometries, including a cylindrical nanorod, a nanorod with one widened end, and a cone-shaped nanorod. The contact between the vesicle protrusion and the sidewall of the rod, neglected in most theoretical studies, is shown to play an important role in regulating vesicle tubulation, membrane tension, and axial contact force on the nanorod. As the nanorod length increases, the confining vesicle evolves from a prolate into different shapes, such as a lemon, a conga drum, a cherry, and a bowling pin, depending on the radical size of the nanorod and the relative vesicle volume. The corresponding morphological phase diagrams are determined. Moreover, phase diagrams of the buckling of the encapsulated nanorods are determined based on the classical Euler buckling theory. It is shown that there exists an optimal filament number at which the encapsulated weakly cross-linked filament bundle maintains the largest length in a mechanically stable state. Similarities and differences between the nanorod packing in vesicles at a given pressure difference and a relative volume are discussed. Our results provide valuable insight into the biophysics underlying cell interactions with one-dimensional and rodlike materials.
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Affiliation(s)
- Zeming Wu
- Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing 100871, China.
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Gong B, Wei X, Qian J, Lin Y. Modeling and Simulations of the Dynamic Behaviors of Actin-Based Cytoskeletal Networks. ACS Biomater Sci Eng 2019; 5:3720-3734. [DOI: 10.1021/acsbiomaterials.8b01228] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Bo Gong
- Department of Engineering Mechanics, Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province, Zhejiang University, Hangzhou, Zhejiang 310027, China
| | - Xi Wei
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China
| | - Jin Qian
- Department of Engineering Mechanics, Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province, Zhejiang University, Hangzhou, Zhejiang 310027, China
| | - Yuan Lin
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China
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Jetta D, Gottlieb PA, Verma D, Sachs F, Hua SZ. Shear stress induced nuclear shrinkage through activation of Piezo1 channels in epithelial cells. J Cell Sci 2019; 132:jcs.226076. [DOI: 10.1242/jcs.226076] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 04/29/2019] [Indexed: 12/30/2022] Open
Abstract
The cell nucleus responds to mechanical cues with changes in size, morphology, and motility. Previous work showed that external forces couple to nuclei through the cytoskeleton network, but we show here that changes in nuclear shape can be driven solely by calcium levels. Fluid shear stress applied to MDCK cells caused the nuclei to shrink through a Ca2+ dependent signaling pathway. Inhibiting mechanosensitive Piezo1 channels with GsMTx4 prevented nuclear shrinkage. Piezo1 knockdown also significantly reduced the nuclear shrinkage. Activation of Piezo1 with the agonist Yoda1 caused similar nucleus shrinkage without shear stress. These results demonstrate that Piezo1 channel is a key element for transmitting shear force input to nuclei. To ascertain the relative contributions of Ca2+ to cytoskeleton perturbation, we examined the F-actin reorganization under shear stress and static conditions, and showed that reorganization of the cytoskeleton is not necessary for nuclear shrinkage. These results emphasize the role of the mechanosensitive channels as primary transducers in force transmission to the nucleus.
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Affiliation(s)
- Deekshitha Jetta
- Department of Mechanical and Aerospace Engineering, University at Buffalo, Buffalo, New York 14260, USA
| | - Philip A. Gottlieb
- Department of Physiology and Biophysics, University at Buffalo, Buffalo, New York 14260, USA
| | - Deepika Verma
- Department of Mechanical and Aerospace Engineering, University at Buffalo, Buffalo, New York 14260, USA
| | - Frederick Sachs
- Department of Physiology and Biophysics, University at Buffalo, Buffalo, New York 14260, USA
| | - Susan Z. Hua
- Department of Mechanical and Aerospace Engineering, University at Buffalo, Buffalo, New York 14260, USA
- Department of Physiology and Biophysics, University at Buffalo, Buffalo, New York 14260, USA
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Zach R, Převorovský M. The phenomenon of lipid metabolism "cut" mutants. Yeast 2018; 35:631-637. [PMID: 30278108 DOI: 10.1002/yea.3358] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 09/06/2018] [Accepted: 09/24/2018] [Indexed: 02/05/2023] Open
Abstract
Every cell cycle iteration culminates with the resolution of a mitotic nucleus into a pair of daughter nuclei, which are distributed between the two daughter cells. In the fission yeast Schizosaccharomyces pombe, the faithful division of a mitotic nucleus depends on unperturbed lipogenesis. Upon genetically or chemically induced perturbation of lipid anabolism, S. pombe cells fail to separate the two daughter nuclei and subsequently initiate lethal cytokinesis resulting in the so-called "cut" terminal phenotype. Evidence supporting a critical role of lipid biogenesis in successful mitosis in S. pombe has been accumulating for almost two decades, but the exact mechanism explaining the reported observations had been elusive. Recently, several studies established a functional link between biosynthesis of structural phospholipids, nuclear membrane growth, and the fidelity of "closed" mitosis in S. pombe. These novel insights suggest a mechanistic explanation for the mitotic defects characteristic for some S. pombe mutants deficient in lipid anabolism and extend our knowledge of metabolic modulation within the context of the cell cycle. In this review, we cover the essential role of lipogenesis in "closed" mitosis, focusing mainly on S. pombe as a model system.
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Affiliation(s)
- Róbert Zach
- Department of Cell Biology, Faculty of Science, Charles University, Prague, Czech Republic.,Genome Damage and Stability Centre, University of Sussex, Brighton, UK
| | - Martin Převorovský
- Department of Cell Biology, Faculty of Science, Charles University, Prague, Czech Republic
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Yi X, Zou G, Gao H. Mechanics of cellular packing of nanorods with finite and non-uniform diameters. NANOSCALE 2018; 10:14090-14099. [PMID: 29999084 DOI: 10.1039/c8nr04110e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
To understand the mechanics of cellular/intracellular packing of one-dimensional nanomaterials, we performed theoretical analysis and molecular dynamics simulations to investigate how the morphology and mechanical behaviors of a lipid vesicle are regulated by encapsulated rigid nanorods of finite and non-uniform diameters, including a cylindrical rod, a rod with widened ends, a cone-shaped rod, and a screwdriver-shaped rod. As the rod length increases, the vesicle evolves from a sphere into different shapes, such as a lemon, a conga drum, a cherry, a bowling pin, or a tubular shape for long and thick rods. The contact between the vesicle protrusion and the rod plays an important role in regulating the vesicle tubulation, membrane tension, and axial contact force on the rod. Our analysis provides a theoretical basis to understand a wide range of experiments on morphological transitions that occur in cellular packing of actin or microtubule bundles, mitotic cell division, and intracellular packing of carbon nanotubes.
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Affiliation(s)
- Xin Yi
- Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing 100871, China and Beijing Innovation Center for Engineering Science and Advanced Technology, Peking University, Beijing 100871, China.
| | - Guijin Zou
- School of Engineering, Brown University, Providence, Rhode Island 02912, USA.
| | - Huajian Gao
- School of Engineering, Brown University, Providence, Rhode Island 02912, USA.
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