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McInally SG, Reading AJB, Rosario A, Jelenkovic PR, Goode BL, Kondev J. Length control emerges from cytoskeletal network geometry. Proc Natl Acad Sci U S A 2024; 121:e2401816121. [PMID: 39106306 PMCID: PMC11331072 DOI: 10.1073/pnas.2401816121] [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: 01/26/2024] [Accepted: 06/21/2024] [Indexed: 08/09/2024] Open
Abstract
Many cytoskeletal networks consist of individual filaments that are organized into elaborate higher-order structures. While it is appreciated that the size and architecture of these networks are critical for their biological functions, much of the work investigating control over their assembly has focused on mechanisms that regulate the turnover of individual filaments through size-dependent feedback. Here, we propose a very different, feedback-independent mechanism to explain how yeast cells control the length of their actin cables. Our findings, supported by quantitative cell imaging and mathematical modeling, indicate that actin cable length control is an emergent property that arises from the cross-linked and bundled organization of the filaments within the cable. Using this model, we further dissect the mechanisms that allow cables to grow longer in larger cells and propose that cell length-dependent tuning of formin activity allows cells to scale cable length with cell length. This mechanism is a significant departure from prior models of cytoskeletal filament length control and presents a different paradigm to consider how cells control the size, shape, and dynamics of higher-order cytoskeletal structures.
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Affiliation(s)
- Shane G. McInally
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA01609
| | | | - Aldric Rosario
- Department of Physics, Brandeis University, Waltham, MA02454
| | | | - Bruce L. Goode
- Department of Biology, Brandeis University, Waltham, MA02454
| | - Jane Kondev
- Department of Physics, Brandeis University, Waltham, MA02454
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2
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Wu W, Lam AR, Suarez K, Smith GN, Duquette SM, Yu J, Mankus D, Bisher M, Lytton-Jean A, Manalis SR, Miettinen TP. Constant surface area-to-volume ratio during cell growth as a design principle in mammalian cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.02.601447. [PMID: 39005340 PMCID: PMC11244959 DOI: 10.1101/2024.07.02.601447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/16/2024]
Abstract
All cells are subject to geometric constraints, such as surface area-to-volume (SA/V) ratio, that impact cell functions and force biological adaptations. Like the SA/V ratio of a sphere, it is generally assumed that the SA/V ratio of cells decreases as cell size increases. Here, we investigate this in near-spherical mammalian cells using single-cell measurements of cell mass and surface proteins, as well as imaging of plasma membrane morphology. We find that the SA/V ratio remains surprisingly constant as cells grow larger. This observation is largely independent of the cell cycle and the amount of cell growth. Consequently, cell growth results in increased plasma membrane folding, which simplifies cellular design by ensuring sufficient membrane area for cell division, nutrient uptake and deformation at all cell sizes.
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Affiliation(s)
- Weida Wu
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Alice R. Lam
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Kayla Suarez
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Grace N. Smith
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Sarah M. Duquette
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Jiaquan Yu
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - David Mankus
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Margaret Bisher
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Abigail Lytton-Jean
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Scott R. Manalis
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Teemu P. Miettinen
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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3
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Kim M, Gorelick AN, Vàzquez-García I, Williams MJ, Salehi S, Shi H, Weiner AC, Ceglia N, Funnell T, Park T, Boscenco S, O'Flanagan CH, Jiang H, Grewal D, Tang C, Rusk N, Gammage PA, McPherson A, Aparicio S, Shah SP, Reznik E. Single-cell mtDNA dynamics in tumors is driven by coregulation of nuclear and mitochondrial genomes. Nat Genet 2024; 56:889-899. [PMID: 38741018 PMCID: PMC11096122 DOI: 10.1038/s41588-024-01724-8] [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: 06/21/2022] [Accepted: 03/20/2024] [Indexed: 05/16/2024]
Abstract
The extent of cell-to-cell variation in tumor mitochondrial DNA (mtDNA) copy number and genotype, and the phenotypic and evolutionary consequences of such variation, are poorly characterized. Here we use amplification-free single-cell whole-genome sequencing (Direct Library Prep (DLP+)) to simultaneously assay mtDNA copy number and nuclear DNA (nuDNA) in 72,275 single cells derived from immortalized cell lines, patient-derived xenografts and primary human tumors. Cells typically contained thousands of mtDNA copies, but variation in mtDNA copy number was extensive and strongly associated with cell size. Pervasive whole-genome doubling events in nuDNA associated with stoichiometrically balanced adaptations in mtDNA copy number, implying that mtDNA-to-nuDNA ratio, rather than mtDNA copy number itself, mediated downstream phenotypes. Finally, multimodal analysis of DLP+ and single-cell RNA sequencing identified both somatic loss-of-function and germline noncoding variants in mtDNA linked to heteroplasmy-dependent changes in mtDNA copy number and mitochondrial transcription, revealing phenotypic adaptations to disrupted nuclear/mitochondrial balance.
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Affiliation(s)
- Minsoo Kim
- Tri-Institutional PhD Program in Computational Biology & Medicine, Weill Cornell Medicine, New York City, NY, USA
- Computational Oncology, Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York City, NY, USA
| | - Alexander N Gorelick
- Computational Oncology, Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York City, NY, USA
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York City, NY, USA
| | - Ignacio Vàzquez-García
- Computational Oncology, Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York City, NY, USA
| | - Marc J Williams
- Computational Oncology, Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York City, NY, USA
| | - Sohrab Salehi
- Computational Oncology, Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York City, NY, USA
| | - Hongyu Shi
- Computational Oncology, Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York City, NY, USA
| | - Adam C Weiner
- Computational Oncology, Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York City, NY, USA
| | - Nick Ceglia
- Computational Oncology, Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York City, NY, USA
| | - Tyler Funnell
- Computational Oncology, Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York City, NY, USA
| | - Tricia Park
- Computational Oncology, Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York City, NY, USA
| | - Sonia Boscenco
- Computational Oncology, Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York City, NY, USA
| | - Ciara H O'Flanagan
- Department of Molecular Oncology, British Columbia Cancer Research Centre, Vancouver, British Columbia, Canada
| | - Hui Jiang
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York City, NY, USA
| | - Diljot Grewal
- Computational Oncology, Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York City, NY, USA
| | - Cerise Tang
- Computational Oncology, Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York City, NY, USA
| | - Nicole Rusk
- Computational Oncology, Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York City, NY, USA
| | - Payam A Gammage
- Institute of Cancer Sciences, University of Glasgow, Glasgow, UK
- CRUK Beatson Institute, Glasgow, UK
| | - Andrew McPherson
- Computational Oncology, Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York City, NY, USA
| | - Sam Aparicio
- Department of Molecular Oncology, British Columbia Cancer Research Centre, Vancouver, British Columbia, Canada
| | - Sohrab P Shah
- Computational Oncology, Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York City, NY, USA.
| | - Ed Reznik
- Computational Oncology, Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York City, NY, USA.
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McInally SG, Reading AJ, Rosario A, Jelenkovic PR, Goode BL, Kondev J. Length control emerges from cytoskeletal network geometry. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.28.569063. [PMID: 38076874 PMCID: PMC10705815 DOI: 10.1101/2023.11.28.569063] [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: 12/22/2023]
Abstract
Many cytoskeletal networks consist of individual filaments that are organized into elaborate higher order structures. While it is appreciated that the size and architecture of these networks are critical for their biological functions, much of the work investigating control over their assembly has focused on mechanisms that regulate the turnover of individual filaments through size-dependent feedback. Here, we propose a very different, feedback-independent mechanism to explain how yeast cells control the length of their actin cables. Our findings, supported by quantitative cell imaging and mathematical modeling, indicate that actin cable length control is an emergent property that arises from the cross-linked and bundled organization of the filaments within the cable. Using this model, we further dissect the mechanisms that allow cables to grow longer in larger cells, and propose that cell length-dependent tuning of formin activity allows cells to scale cable length with cell length. This mechanism is a significant departure from prior models of cytoskeletal filament length control and presents a new paradigm to consider how cells control the size, shape, and dynamics of higher order cytoskeletal structures.
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Affiliation(s)
- Shane G. McInally
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA, 01609, USA
| | | | - Aldric Rosario
- Department of Physics, Brandeis University, Waltham, MA, 02454, USA
| | | | - Bruce L. Goode
- Department of Biology, Brandeis University, Waltham, MA, 02454, USA
| | - Jane Kondev
- Department of Physics, Brandeis University, Waltham, MA, 02454, USA
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5
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KYOGOKU H, KITAJIMA TS. The large cytoplasmic volume of oocyte. J Reprod Dev 2023; 69:1-9. [PMID: 36436912 PMCID: PMC9939283 DOI: 10.1262/jrd.2022-101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
The study of the size of cells and organelles has a long history, dating back to the 1600s when cells were defined. In particular, various methods have elucidated the size of the nucleus and the mitotic spindle in several species. However, little research has been conducted on oocyte size and organelles in mammals, and many questions remain to be answered. The appropriate size is essential to cell function properly. Oocytes have a very large cytoplasm, which is more than 100 times larger than that of general somatic cells in mammals. In this review, we discuss how oocytes acquire an enormous cytoplasmic size and the adverse effects of a large cytoplasmic size on cellular functions.
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Affiliation(s)
- Hirohisa KYOGOKU
- Graduate School of Agricultural Science, Kobe University, Kobe 657-8501, Japan,Laboratory for Chromosome Segregation, RIKEN Center for Biosystems Dynamics Research, Kobe 650-0047, Japan
| | - Tomoya S KITAJIMA
- Laboratory for Chromosome Segregation, RIKEN Center for Biosystems Dynamics Research, Kobe 650-0047, Japan
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6
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Steinacker TL, Wong SS, Novak ZA, Saurya S, Gartenmann L, van Houtum EJ, Sayers JR, Lagerholm BC, Raff JW. Centriole growth is limited by the Cdk/Cyclin-dependent phosphorylation of Ana2/STIL. J Cell Biol 2022; 221:e202205058. [PMID: 35861803 PMCID: PMC9442473 DOI: 10.1083/jcb.202205058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 06/29/2022] [Accepted: 07/06/2022] [Indexed: 11/25/2022] Open
Abstract
Centrioles duplicate once per cell cycle, but it is unclear how daughter centrioles assemble at the right time and place and grow to the right size. Here, we show that in Drosophila embryos the cytoplasmic concentrations of the key centriole assembly proteins Asl, Plk4, Ana2, Sas-6, and Sas-4 are low, but remain constant throughout the assembly process-indicating that none of them are limiting for centriole assembly. The cytoplasmic diffusion rate of Ana2/STIL, however, increased significantly toward the end of S-phase as Cdk/Cyclin activity in the embryo increased. A mutant form of Ana2 that cannot be phosphorylated by Cdk/Cyclins did not exhibit this diffusion change and allowed daughter centrioles to grow for an extended period. Thus, the Cdk/Cyclin-dependent phosphorylation of Ana2 seems to reduce the efficiency of daughter centriole assembly toward the end of S-phase. This helps to ensure that daughter centrioles stop growing at the correct time, and presumably also helps to explain why centrioles cannot duplicate during mitosis.
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Affiliation(s)
| | - Siu-Shing Wong
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Zsofia A. Novak
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Saroj Saurya
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Lisa Gartenmann
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | | | - Judith R. Sayers
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | | | - Jordan W. Raff
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
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7
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Glazier DS. How Metabolic Rate Relates to Cell Size. BIOLOGY 2022; 11:1106. [PMID: 35892962 PMCID: PMC9332559 DOI: 10.3390/biology11081106] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 07/20/2022] [Accepted: 07/21/2022] [Indexed: 12/19/2022]
Abstract
Metabolic rate and its covariation with body mass vary substantially within and among species in little understood ways. Here, I critically review explanations (and supporting data) concerning how cell size and number and their establishment by cell expansion and multiplication may affect metabolic rate and its scaling with body mass. Cell size and growth may affect size-specific metabolic rate, as well as the vertical elevation (metabolic level) and slope (exponent) of metabolic scaling relationships. Mechanistic causes of negative correlations between cell size and metabolic rate may involve reduced resource supply and/or demand in larger cells, related to decreased surface area per volume, larger intracellular resource-transport distances, lower metabolic costs of ionic regulation, slower cell multiplication and somatic growth, and larger intracellular deposits of metabolically inert materials in some tissues. A cell-size perspective helps to explain some (but not all) variation in metabolic rate and its body-mass scaling and thus should be included in any multi-mechanistic theory attempting to explain the full diversity of metabolic scaling. A cell-size approach may also help conceptually integrate studies of the biological regulation of cellular growth and metabolism with those concerning major transitions in ontogenetic development and associated shifts in metabolic scaling.
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8
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Datta A, Ghosh S, Kondev J. How to assemble a scale-invariant gradient. eLife 2022; 11:71365. [PMID: 35311649 PMCID: PMC8986316 DOI: 10.7554/elife.71365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 03/20/2022] [Indexed: 11/17/2022] Open
Abstract
Intracellular protein gradients serve a variety of functions, such as the establishment of cell polarity or to provide positional information for gene expression in developing embryos. Given that cell size in a population can vary considerably, for the protein gradients to work properly they often have to be scaled to the size of the cell. Here, we examine a model of protein gradient formation within a cell that relies on cytoplasmic diffusion and cortical transport of proteins toward a cell pole. We show that the shape of the protein gradient is determined solely by the cell geometry. Furthermore, we show that the length scale over which the protein concentration in the gradient varies is determined by the linear dimensions of the cell, independent of the diffusion constant or the transport speed. This gradient provides scale-invariant positional information within a cell, which can be used for assembly of intracellular structures whose size is scaled to the linear dimensions of the cell, such as the cytokinetic ring and actin cables in budding yeast cells.
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Affiliation(s)
- Arnab Datta
- Department of Physics, Brandeis University, Waltham, United States
| | - Sagnik Ghosh
- Department of Physics, Brandeis University, Waltham, United States
| | - Jane Kondev
- Department of Physics, Brandeis University, Waltham, United States
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9
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Whole and Purified Aqueous Extracts of Nigella sativa L. Seeds Attenuate Apoptosis and the Overproduction of Reactive Oxygen Species Triggered by p53 Over-Expression in the Yeast Saccharomyces cerevisiae. Cells 2022; 11:cells11050869. [PMID: 35269491 PMCID: PMC8909299 DOI: 10.3390/cells11050869] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 02/24/2022] [Accepted: 02/28/2022] [Indexed: 02/04/2023] Open
Abstract
Plants are an important source of pharmacologically active compounds. In the present work, we characterize the impact of black cumin (Nigella sativa L.) aqueous extracts on a yeast model of p53-dependent apoptosis. To this end, the Saccharomyces cerevisiae recombinant strain over-expressing p53 was used. The over-expression of p53 triggers the expression of apoptotic markers: the externalization of phosphatidylserine, mitochondrial defect associated with cytochrome-c release and the induction of DNA strand breaks. These different effects were attenuated by Nigella sativa L. aqueous extracts, whereas these extracts have no effect on the level of p53 expression. Thus, we focus on the anti-apoptotic molecules present in the aqueous extract of Nigella sativa L. These extracts were purified and characterized by complementary chromatographic methods. Specific fluorescent probes were used to determine the effect of the extracts on yeast apoptosis. Yeast cells over-expressing p53 decrease in relative size and have lower mitochondrial content. The decrease in cell size was proportional to the decrease in mitochondrial content and of mitochondrial membrane potential (ΔΨm). These effects were prevented by the purified aqueous fraction obtained by fractionation with different columns, named C4 fraction. Yeast cell death was also characterized by reactive oxygen species (ROS) overproduction. In the presence of the C4 fraction, ROS overproduction was strongly reduced. We also noted that the C4 fraction promotes the cell growth of control yeast cells, which do not express p53, supporting the fact that this purified extract acts on cellular mediators activating cell proliferation independently of p53. Altogether, our data obtained on yeast cells over-expressing p53 demonstrate that anti-apoptotic molecules targeting p53-induced apoptosis associated with mitochondrial dysfunction and ROS overproduction are present in the aqueous extracts of Nigella seeds and in the purified aqueous C4 fraction.
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10
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Khatri D, Brugière T, Athale CA, Delattre M. Evolutionary divergence of anaphase spindle mechanics in nematode embryos constrained by antagonistic pulling and viscous forces. Mol Biol Cell 2022; 33:ar61. [PMID: 35235368 PMCID: PMC9265157 DOI: 10.1091/mbc.e21-10-0532] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Cellular functions like cell division are remarkably conserved across phyla. However the evolutionary principles of cellular organization that drive it are less well explored. Thus, an essential question remains: to what extent cellular parameters evolve without altering the basic function they sustain? Here we have observed 6 different nematode species for which the mitotic spindle is positioned asymmetrically during the first embryonic division. Whereas the C. elegans spindle undergoes oscillations during its displacement, the spindle elongates without oscillations in other species. We asked which evolutionary changes in biophysical parameters could explain differences in spindle motion while maintaining a constant output. Using laser microsurgery of the spindle we revealed that all species are subjected to cortical pulling forces, of varying magnitudes. Using a viscoelastic model to fit the recoil trajectories and with an independent measurement of cytoplasmic viscosity, we extracted the values of cytoplasmic drag, cortical pulling forces and spindle elasticity for all species. We found large variations in cytoplasmic viscosity whereas cortical pulling forces and elasticity were often more constrained. In agreement with previous simulations, we found that increased viscosity correlates with decreased oscillation speeds across species. However, the absence of oscillations despite low viscosity in some species, can only be explained by smaller pulling forces. Consequently, we find that spindle mobility across the species analyzed here is characterized by a tradeoff between cytoplasmic viscosity and pulling forces normalized by the size of the embryo. Our work provides a framework for understanding mechanical constraints on evolutionary diversification of spindle mobility.
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Affiliation(s)
- Dhruv Khatri
- Div. of Biology, IISER Pune, Dr. Homi Bhabha Road, Pashan, Pune 411008, India
| | - Thibault Brugière
- Laboratory of Biology and Modeling of the Cell, Ecole Normale Supérieure de Lyon, CNRS, Inserm, UCBL, 69007 Lyon, France
| | - Chaitanya A Athale
- Div. of Biology, IISER Pune, Dr. Homi Bhabha Road, Pashan, Pune 411008, India
| | - Marie Delattre
- Laboratory of Biology and Modeling of the Cell, Ecole Normale Supérieure de Lyon, CNRS, Inserm, UCBL, 69007 Lyon, France
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11
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Suen JY, Navlakha S. A feedback control principle common to several biological and engineered systems. J R Soc Interface 2022; 19:20210711. [PMID: 35232277 PMCID: PMC8889180 DOI: 10.1098/rsif.2021.0711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 02/02/2022] [Indexed: 11/12/2022] Open
Abstract
Feedback control is used by many distributed systems to optimize behaviour. Traditional feedback control algorithms spend significant resources to constantly sense and stabilize a continuous control variable of interest, such as vehicle speed for implementing cruise control, or body temperature for maintaining homeostasis. By contrast, discrete-event feedback (e.g. a server acknowledging when data are successfully transmitted, or a brief antennal interaction when an ant returns to the nest after successful foraging) can reduce costs associated with monitoring a continuous variable; however, optimizing behaviour in this setting requires alternative strategies. Here, we studied parallels between discrete-event feedback control strategies in biological and engineered systems. We found that two common engineering rules-additive-increase, upon positive feedback, and multiplicative-decrease, upon negative feedback, and multiplicative-increase multiplicative-decrease-are used by diverse biological systems, including for regulating foraging by harvester ant colonies, for maintaining cell-size homeostasis, and for synaptic learning and adaptation in neural circuits. These rules support several goals of these systems, including optimizing efficiency (i.e. using all available resources); splitting resources fairly among cooperating agents, or conversely, acquiring resources quickly among competing agents; and minimizing the latency of responses, especially when conditions change. We hypothesize that theoretical frameworks from distributed computing may offer new ways to analyse adaptation behaviour of biology systems, and in return, biological strategies may inspire new algorithms for discrete-event feedback control in engineering.
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Affiliation(s)
- Jonathan Y. Suen
- Cold Spring Harbor Laboratory, Simons Center for Quantitative Biology, Cold Spring Harbor, NY, USA
| | - Saket Navlakha
- Cold Spring Harbor Laboratory, Simons Center for Quantitative Biology, Cold Spring Harbor, NY, USA
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12
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Rashid U, Yousaf A, Yaqoob M, Saba E, Moaeen-Ud-Din M, Waseem S, Becker SK, Sponder G, Aschenbach JR, Sandhu MA. Characterization and differentiation potential of mesenchymal stem cells isolated from multiple canine adipose tissue sources. BMC Vet Res 2021; 17:388. [PMID: 34922529 PMCID: PMC8684202 DOI: 10.1186/s12917-021-03100-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 11/29/2021] [Indexed: 12/16/2022] Open
Abstract
Background Mesenchymal stem cells (MSCs) are undifferentiated cells that can give rise to a mesoderm lineage. Adipose-derived MSCs are an easy and accessible source for MSCs isolation, although each source of MSC has its own advantages and disadvantages. Our study identifies a promising source for the isolation and differentiation of canines MSCs. For this purpose, adipose tissue from inguinal subcutaneous (SC), perirenal (PR), omental (OM), and infrapatellar fat pad (IPFP) was isolated and processed for MSCs isolation. In the third passage, MSCs proliferation/metabolism, surface markers expression, in vitro differentiation potential and quantitative reverse transcription PCR (CD73, CD90, CD105, PPARγ, FabP4, FAS, SP7, Osteopontin, and Osteocalcin) were evaluated. Results Our results showed that MSCs derived from IPFP have a higher proliferation rate, while OM-derived MSCs have higher cell metabolism. In addition, MSCs from all adipose tissue sources showed positive expression of CD73 (NT5E), CD90 (THY1), CD105 (ENDOGLIN), and very low expression of CD45. The isolated canine MSCs were successfully differentiated into adipogenic and osteogenic lineages. The oil-red-O quantification and adipogenic gene expression (FAS, FabP4, and PPARγ) were higher in OM-derived cells, followed by IPFP-MSCs. Similarly, in osteogenic differentiation, alkaline phosphatase activity and osteogenic gene (SP7 and Osteocalcin) expression were higher in OM-derived MSCs, while osteopontin expression was higher in PR-derived MSCs. Conclusion In summary, among all four adipose tissue sources, OM-derived MSCs have better differentiation potential toward adipo- and osteogenic lineages, followed by IPFP-MSCs. Interestingly, among all adipose tissue sources, MSCs derived from IPFP have the maximum proliferation potential. The characterization and differentiation potential of canine MSCs isolated from four different adipose tissue sources are useful to assess their potential for application in regenerative medicine.
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Affiliation(s)
- Usman Rashid
- Department of Clinical Studies, Faculty of Veterinary and Animal Sciences, PMAS-Arid Agriculture University, Rawalpindi, 46300, Pakistan
| | - Arfan Yousaf
- Department of Clinical Studies, Faculty of Veterinary and Animal Sciences, PMAS-Arid Agriculture University, Rawalpindi, 46300, Pakistan
| | - Muhammad Yaqoob
- Department of Clinical Studies, Faculty of Veterinary and Animal Sciences, PMAS-Arid Agriculture University, Rawalpindi, 46300, Pakistan
| | - Evelyn Saba
- Department of Veterinary Biomedical Sciences, Faculty of Veterinary and Animal Sciences, PMAS-Arid Agriculture University, Rawalpindi, 46300, Pakistan
| | - Muhammad Moaeen-Ud-Din
- Department of Animal Breeding and Genetics, Faculty of Veterinary and Animal Sciences, PMAS-Arid Agriculture University, Rawalpindi, 46300, Pakistan
| | | | - Sandra K Becker
- Institute of Veterinary-Physiology, Freie Universität Berlin, Berlin, Germany
| | - Gerhard Sponder
- Institute of Veterinary-Physiology, Freie Universität Berlin, Berlin, Germany
| | - Jörg R Aschenbach
- Institute of Veterinary-Physiology, Freie Universität Berlin, Berlin, Germany
| | - Mansur Abdullah Sandhu
- Department of Veterinary Biomedical Sciences, Faculty of Veterinary and Animal Sciences, PMAS-Arid Agriculture University, Rawalpindi, 46300, Pakistan.
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13
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Racicot KJ, Popic C, Cunha F, Wright D, Henriksen R, Iwaniuk AN. The cerebellar anatomy of red junglefowl and white leghorn chickens: insights into the effects of domestication on the cerebellum. ROYAL SOCIETY OPEN SCIENCE 2021; 8:211002. [PMID: 34659779 PMCID: PMC8511745 DOI: 10.1098/rsos.211002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 09/17/2021] [Indexed: 05/07/2023]
Abstract
Domestication is the process by which wild organisms become adapted for human use. Many phenotypic changes are associated with animal domestication, including decreases in brain and brain region sizes. In contrast with this general pattern, the chicken has a larger cerebellum compared with the wild red junglefowl, but what neuroanatomical changes are responsible for this difference have yet to be investigated. Here, we quantified cell layer volumes, neuron numbers and neuron sizes in the cerebella of chickens and junglefowl. Chickens have larger, more folded cerebella with more and larger granule cells than junglefowl, but neuron numbers and cerebellar folding were proportional to cerebellum size. However, chickens do have relatively larger granule cell layer volumes and relatively larger granule cells than junglefowl. Thus, the chicken cerebellum can be considered a scaled-up version of the junglefowl cerebellum, but with enlarged granule cells. The combination of scaling neuron number and disproportionate enlargement of cell bodies partially supports a recent theory that domestication does not affect neuronal density within brain regions. Whether the neuroanatomical changes we observed are typical of domestication or not requires similar quantitative analyses in other domesticated species and across multiple brain regions.
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Affiliation(s)
- Kelsey J. Racicot
- Department of Neuroscience, University of Lethbridge, Lethbridge, Alberta, Canada T1K3M4
| | - Christina Popic
- Department of Neuroscience, University of Lethbridge, Lethbridge, Alberta, Canada T1K3M4
| | - Felipe Cunha
- Department of Neuroscience, University of Lethbridge, Lethbridge, Alberta, Canada T1K3M4
| | - Dominic Wright
- AVIAN Behavioural Genomics and Physiology Group, IFM Biology, Linköping University, Linköping 58183, Sweden
| | - Rie Henriksen
- AVIAN Behavioural Genomics and Physiology Group, IFM Biology, Linköping University, Linköping 58183, Sweden
| | - Andrew N. Iwaniuk
- Department of Neuroscience, University of Lethbridge, Lethbridge, Alberta, Canada T1K3M4
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14
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Cunha F, Gutiérrez-Ibáñez C, Racicot K, Wylie DR, Iwaniuk AN. A quantitative analysis of cerebellar anatomy in birds. Brain Struct Funct 2021; 226:2561-2583. [PMID: 34357439 DOI: 10.1007/s00429-021-02352-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 07/26/2021] [Indexed: 12/19/2022]
Abstract
The cerebellum is largely conserved in its circuitry, but varies greatly in size and shape across species. The extent to which differences in cerebellar morphology is driven by changes in neuron numbers, neuron sizes or both, remains largely unknown. To determine how species variation in cerebellum size and shape is reflective of neuron sizes and numbers requires the development of a suitable comparative data set and one that can effectively separate different neuronal populations. Here, we generated the largest comparative dataset to date on neuron numbers, sizes, and volumes of cortical layers and surface area of the cerebellum across 54 bird species. Across different cerebellar sizes, the cortical layers maintained relatively constant proportions to one another and variation in cerebellum size was largely due to neuron numbers rather than neuron sizes. However, the rate at which neuron numbers increased with cerebellum size varied across Purkinje cells, granule cells, and cerebellar nuclei neurons. We also examined the relationship among neuron numbers, cerebellar surface area and cerebellar folding. Our estimate of cerebellar folding, the midsagittal foliation index, was a poor predictor of surface area and number of Purkinje cells, but surface area was the best predictor of Purkinje cell numbers. Overall, this represents the first comprehensive, quantitative analysis of cerebellar anatomy in a comparative context of any vertebrate. The extent to which these relationships occur in other vertebrates requires a similar approach and would determine whether the same scaling principles apply throughout the evolution of the cerebellum.
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Affiliation(s)
- Felipe Cunha
- Department of Neuroscience, University of Lethbridge, 4401 University Dr. W, Science & Academic Building, SA8150, Lethbridge, AB, T1K 6T5, Canada.
| | | | - Kelsey Racicot
- Department of Neuroscience, University of Lethbridge, 4401 University Dr. W, Science & Academic Building, SA8150, Lethbridge, AB, T1K 6T5, Canada
| | - Douglas R Wylie
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Andrew N Iwaniuk
- Department of Neuroscience, University of Lethbridge, 4401 University Dr. W, Science & Academic Building, SA8150, Lethbridge, AB, T1K 6T5, Canada
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15
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McInally SG, Kondev J, Goode BL. Scaling of subcellular actin structures with cell length through decelerated growth. eLife 2021; 10:68424. [PMID: 34114567 PMCID: PMC8233038 DOI: 10.7554/elife.68424] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 06/10/2021] [Indexed: 12/11/2022] Open
Abstract
How cells tune the size of their subcellular parts to scale with cell size is a fundamental question in cell biology. Until now, most studies on the size control of organelles and other subcellular structures have focused on scaling relationships with cell volume, which can be explained by limiting pool mechanisms. Here, we uncover a distinct scaling relationship with cell length rather than volume, revealed by mathematical modeling and quantitative imaging of yeast actin cables. The extension rate of cables decelerates as they approach the rear of the cell, until cable length matches cell length. Further, the deceleration rate scales with cell length. These observations are quantitatively explained by a ‘balance-point’ model, which stands in contrast to limiting pool mechanisms, and describes a distinct mode of self-assembly that senses the linear dimensions of the cell.
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Affiliation(s)
- Shane G McInally
- Department of Biology, Brandeis University, Waltham, United States.,Department of Physics, Brandeis University, Waltham, United States
| | - Jane Kondev
- Department of Physics, Brandeis University, Waltham, United States
| | - Bruce L Goode
- Department of Biology, Brandeis University, Waltham, United States
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16
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Rieckhoff EM, Berndt F, Elsner M, Golfier S, Decker F, Ishihara K, Brugués J. Spindle Scaling Is Governed by Cell Boundary Regulation of Microtubule Nucleation. Curr Biol 2020; 30:4973-4983.e10. [DOI: 10.1016/j.cub.2020.10.093] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 10/11/2020] [Accepted: 10/29/2020] [Indexed: 02/08/2023]
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17
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Abstract
As cells grow, the size and number of their internal organelles increase in order to keep up with increased metabolic requirements. Abnormal size of organelles is a hallmark of cancer and an important aspect of diagnosis in cytopathology. Most organelles vary in either size or number, or both, as a function of cell size, but the mechanisms that create this variation remain unclear. In some cases, organelle size appears to scale with cell size through processes of relative growth, but in others the size may be set by either active measurement systems or genetic programs that instruct organelle biosynthetic activities to create organelles of a size appropriate to a given cell type.
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Affiliation(s)
- Wallace F Marshall
- Department of Biochemistry and Biophysics, University of California, San Francisco, California 94143, USA;
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18
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Activity-dependent compensation of cell size is vulnerable to targeted deletion of ion channels. Sci Rep 2020; 10:15989. [PMID: 32994529 PMCID: PMC7524806 DOI: 10.1038/s41598-020-72977-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 08/25/2020] [Indexed: 01/13/2023] Open
Abstract
In many species, excitable cells preserve their physiological properties despite significant variation in physical size across time and in a population. For example, neurons in crustacean central pattern generators generate similar firing patterns despite several-fold increases in size between juveniles and adults. This presents a biophysical problem because the electrical properties of cells are highly sensitive to membrane area and channel density. It is not known whether specific mechanisms exist to sense membrane area and adjust channel expression to keep a consistent channel density, or whether regulation mechanisms that sense activity alone are capable of compensating cell size. We show that destabilising effects of growth can be specifically compensated by feedback mechanism that senses average calcium influx and jointly regulate multiple conductances. However, we further show that this class of growth-compensating regulation schemes is necessarily sensitive to perturbations that alter the expression of subsets of ion channel types. Targeted perturbations of specific ion channels can trigger a pathological response of the regulation mechanism and a failure of homeostasis. Our findings suggest that physiological regulation mechanisms that confer robustness to growth may be specifically vulnerable to deletions or mutations that affect subsets of ion channels.
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19
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Geisterfer ZM, Zhu DY, Mitchison TJ, Oakey J, Gatlin JC. Microtubule Growth Rates Are Sensitive to Global and Local Changes in Microtubule Plus-End Density. Curr Biol 2020; 30:3016-3023.e3. [PMID: 32531285 DOI: 10.1016/j.cub.2020.05.056] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2020] [Revised: 04/14/2020] [Accepted: 05/18/2020] [Indexed: 01/02/2023]
Abstract
The microtubule cytoskeleton plays critically important roles in numerous cellular functions in eukaryotes, and it does so across a functionally diverse and morphologically disparate range of cell types [1]. In these roles, microtubule assemblies must adopt distinct morphologies and physical dimensions to perform specific functions [2-5]. As such, these macromolecular assemblies-as well as the dynamics of the individual microtubule polymers from which they are made-must scale and change in accordance with cell size, geometry, and function. Microtubules in cells typically assemble to a steady state in mass, leaving enough of their tubulin subunits soluble to allow rapid growth and turnover. This suggests some negative feedback that limits the extent of assembly, for example, decrease in growth rate, or increase in catastrophe rate, as the soluble subunit pool decreases. Although these ideas have informed the field for decades, they have not been observed experimentally. Here, we describe the application of an experimental approach that combines cell-free extracts with photo-patterned hydrogel micro-enclosures as a means to investigate microtubule dynamics in cytoplasmic volumes of defined size and shape. Our measurements reveal a negative correlation between microtubule plus-end density and microtubule growth rates and suggest that these rates are sensitive to the presence of nearby growing ends.
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Affiliation(s)
- Zachary M Geisterfer
- Department of Molecular Biology, University of Wyoming, 1000 E. University Avenue, Laramie, WY 82070, USA.
| | - Daniel Y Zhu
- Department of Molecular Biology, University of Wyoming, 1000 E. University Avenue, Laramie, WY 82070, USA
| | - Timothy J Mitchison
- Department of Systems Biology, Harvard Medical School, 25 Shattuck Street, Boston, MA 02115, USA; Marine Biological Laboratory, Cell Division and Organization Group, 7 MBL Street, Woods Hole, MA 02543, USA
| | - John Oakey
- Marine Biological Laboratory, Cell Division and Organization Group, 7 MBL Street, Woods Hole, MA 02543, USA; Department of Chemical Engineering, University of Wyoming, 1000 E. University Avenue, Laramie, WY 82070, USA
| | - Jesse C Gatlin
- Department of Molecular Biology, University of Wyoming, 1000 E. University Avenue, Laramie, WY 82070, USA; Marine Biological Laboratory, Cell Division and Organization Group, 7 MBL Street, Woods Hole, MA 02543, USA.
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20
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Hirst WG, Biswas A, Mahalingan KK, Reber S. Differences in Intrinsic Tubulin Dynamic Properties Contribute to Spindle Length Control in Xenopus Species. Curr Biol 2020; 30:2184-2190.e5. [PMID: 32386526 DOI: 10.1016/j.cub.2020.03.067] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 02/13/2020] [Accepted: 03/26/2020] [Indexed: 01/21/2023]
Abstract
The function of cellular organelles relates not only to their molecular composition but also to their size. However, how the size of dynamic mesoscale structures is established and maintained remains poorly understood [1-3]. Mitotic spindle length, for example, varies several-fold among cell types and among different organisms [4]. Although most studies on spindle size control focus on changes in proteins that regulate microtubule dynamics [5-8], the contribution of the spindle's main building block, the αβ-tubulin heterodimer, has yet to be studied. Apart from microtubule-associated proteins and motors, two factors have been shown to contribute to the heterogeneity of microtubule dynamics: tubulin isoform composition [9, 10] and post-translational modifications [11]. In the past, studying the contribution of tubulin and microtubules to spindle assembly has been limited by the fact that physiologically relevant tubulins were not available. Here, we show that tubulins purified from two closely related frogs, Xenopus laevis and Xenopus tropicalis, have surprisingly different microtubule dynamics in vitro. X. laevis microtubules combine very fast growth and infrequent catastrophes. In contrast, X. tropicalis microtubules grow slower and catastrophe more frequently. We show that spindle length and microtubule mass can be controlled by titrating the ratios of the tubulins from the two frog species. Furthermore, we combine our in vitro reconstitution assay and egg extract experiments with computational modeling to show that differences in intrinsic properties of different tubulins contribute to the control of microtubule mass and therefore set steady-state spindle length.
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Affiliation(s)
- William G Hirst
- IRI Life Sciences, Humboldt-Universität zu Berlin, 10115 Berlin, Germany; Research School of Biology, The Australian National University, Canberra, ACT 2600, Australia; Marine Biological Laboratory, Woods Hole, MA 02543, USA
| | - Abin Biswas
- IRI Life Sciences, Humboldt-Universität zu Berlin, 10115 Berlin, Germany; Marine Biological Laboratory, Woods Hole, MA 02543, USA
| | | | - Simone Reber
- IRI Life Sciences, Humboldt-Universität zu Berlin, 10115 Berlin, Germany; Marine Biological Laboratory, Woods Hole, MA 02543, USA; University of Applied Sciences Berlin, 13353 Berlin, Germany.
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21
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Zatulovskiy E, Skotheim JM. On the Molecular Mechanisms Regulating Animal Cell Size Homeostasis. Trends Genet 2020; 36:360-372. [PMID: 32294416 PMCID: PMC7162994 DOI: 10.1016/j.tig.2020.01.011] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 01/28/2020] [Accepted: 01/28/2020] [Indexed: 12/19/2022]
Abstract
Cell size is fundamental to cell physiology because it sets the scale of intracellular geometry, organelles, and biosynthetic processes. In animal cells, size homeostasis is controlled through two phenomenologically distinct mechanisms. First, size-dependent cell cycle progression ensures that smaller cells delay cell cycle progression to accumulate more biomass than larger cells prior to cell division. Second, size-dependent cell growth ensures that larger and smaller cells grow slower per unit mass than more optimally sized cells. This decade has seen dramatic progress in single-cell technologies establishing the diverse phenomena of cell size control in animal cells. Here, we review this recent progress and suggest pathways forward to determine the underlying molecular mechanisms.
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Affiliation(s)
| | - Jan M Skotheim
- Department of Biology, Stanford University, Stanford, CA 94305, USA.
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22
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Gray WT, Govers SK, Xiang Y, Parry BR, Campos M, Kim S, Jacobs-Wagner C. Nucleoid Size Scaling and Intracellular Organization of Translation across Bacteria. Cell 2020; 177:1632-1648.e20. [PMID: 31150626 DOI: 10.1016/j.cell.2019.05.017] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 04/01/2019] [Accepted: 05/08/2019] [Indexed: 01/10/2023]
Abstract
The scaling of organelles with cell size is thought to be exclusive to eukaryotes. Here, we demonstrate that similar scaling relationships hold for the bacterial nucleoid. Despite the absence of a nuclear membrane, nucleoid size strongly correlates with cell size, independent of changes in DNA amount and across various nutrient conditions. This correlation is observed in diverse bacteria, revealing a near-constant ratio between nucleoid and cell size for a given species. As in eukaryotes, the nucleocytoplasmic ratio in bacteria varies greatly among species. This spectrum of nucleocytoplasmic ratios is independent of genome size, and instead it appears linked to the average population cell size. Bacteria with different nucleocytoplasmic ratios have a cytoplasm with different biophysical properties, impacting ribosome mobility and localization. Together, our findings identify new organizational principles and biophysical features of bacterial cells, implicating the nucleocytoplasmic ratio and cell size as determinants of the intracellular organization of translation.
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Affiliation(s)
- William T Gray
- Microbial Sciences Institute, Yale University, West Haven, CT, USA; Department of Pharmacology, Yale University, New Haven, CT, USA
| | - Sander K Govers
- Microbial Sciences Institute, Yale University, West Haven, CT, USA; Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | - Yingjie Xiang
- Microbial Sciences Institute, Yale University, West Haven, CT, USA; Department of Mechanical Engineering and Materials Science, Yale University, New Haven, CT, USA
| | - Bradley R Parry
- Microbial Sciences Institute, Yale University, West Haven, CT, USA; Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | - Manuel Campos
- Microbial Sciences Institute, Yale University, West Haven, CT, USA; Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | - Sangjin Kim
- Microbial Sciences Institute, Yale University, West Haven, CT, USA; Department of Mechanical Engineering and Materials Science, Yale University, New Haven, CT, USA
| | - Christine Jacobs-Wagner
- Microbial Sciences Institute, Yale University, West Haven, CT, USA; Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA; Howard Hughes Medical Institute, Yale University, New Haven, CT, USA; Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, CT, USA.
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23
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Krüger LK, Sanchez JL, Paoletti A, Tran PT. Kinesin-6 regulates cell-size-dependent spindle elongation velocity to keep mitosis duration constant in fission yeast. eLife 2019; 8:42182. [PMID: 30806623 PMCID: PMC6391065 DOI: 10.7554/elife.42182] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 02/13/2019] [Indexed: 01/01/2023] Open
Abstract
The length of the mitotic spindle scales with cell size in a wide range of organisms during embryonic development. Interestingly, in C. elegans embryos, this goes along with temporal regulation: larger cells speed up spindle assembly and elongation. We demonstrate that, similarly in fission yeast, spindle length and spindle dynamics adjust to cell size, which allows to keep mitosis duration constant. Since prolongation of mitosis was shown to affect cell viability, this may resemble a mechanism to regulate mitosis duration. We further reveal how the velocity of spindle elongation is regulated: coupled to cell size, the amount of kinesin-6 Klp9 molecules increases, resulting in an acceleration of spindle elongation in anaphase B. In addition, the number of Klp9 binding sites to microtubules increases overproportionally to Klp9 molecules, suggesting that molecular crowding inversely correlates to cell size and might have an impact on spindle elongation velocity control.
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Affiliation(s)
| | | | - Anne Paoletti
- Institut Curie, PSL Research University, CNRS, UMR 144, Paris, France
| | - Phong Thanh Tran
- Institut Curie, PSL Research University, CNRS, UMR 144, Paris, France.,Department of Cell and Developmental Biology, University of Pennsylvania, Philadelphia, United States
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24
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Lacroix B, Letort G, Pitayu L, Sallé J, Stefanutti M, Maton G, Ladouceur AM, Canman JC, Maddox PS, Maddox AS, Minc N, Nédélec F, Dumont J. Microtubule Dynamics Scale with Cell Size to Set Spindle Length and Assembly Timing. Dev Cell 2018; 45:496-511.e6. [PMID: 29787710 DOI: 10.1016/j.devcel.2018.04.022] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 03/22/2018] [Accepted: 04/24/2018] [Indexed: 12/22/2022]
Abstract
Successive cell divisions during embryonic cleavage create increasingly smaller cells, so intracellular structures must adapt accordingly. Mitotic spindle size correlates with cell size, but the mechanisms for this scaling remain unclear. Using live cell imaging, we analyzed spindle scaling during embryo cleavage in the nematode Caenorhabditis elegans and sea urchin Paracentrotus lividus. We reveal a common scaling mechanism, where the growth rate of spindle microtubules scales with cell volume, which explains spindle shortening. Spindle assembly timing is, however, constant throughout successive divisions. Analyses in silico suggest that controlling the microtubule growth rate is sufficient to scale spindle length and maintain a constant assembly timing. We tested our in silico predictions to demonstrate that modulating cell volume or microtubule growth rate in vivo induces a proportional spindle size change. Our results suggest that scalability of the microtubule growth rate when cell size varies adapts spindle length to cell volume.
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Affiliation(s)
- Benjamin Lacroix
- Institut Jacques Monod, CNRS, UMR 7592, University Paris Diderot, Sorbonne Paris Cité, 75205 Paris, France.
| | - Gaëlle Letort
- Institut Curie, Mines Paris Tech, Inserm, U900, PSL Research University, 75005 Paris, France
| | - Laras Pitayu
- Institut Jacques Monod, CNRS, UMR 7592, University Paris Diderot, Sorbonne Paris Cité, 75205 Paris, France
| | - Jérémy Sallé
- Institut Jacques Monod, CNRS, UMR 7592, University Paris Diderot, Sorbonne Paris Cité, 75205 Paris, France
| | - Marine Stefanutti
- Institut Jacques Monod, CNRS, UMR 7592, University Paris Diderot, Sorbonne Paris Cité, 75205 Paris, France
| | - Gilliane Maton
- Institut Jacques Monod, CNRS, UMR 7592, University Paris Diderot, Sorbonne Paris Cité, 75205 Paris, France
| | | | - Julie C Canman
- Columbia University Medical Center, Department of Pathology and Cell Biology, New York, NY 10032, USA
| | - Paul S Maddox
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Amy S Maddox
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Nicolas Minc
- Institut Jacques Monod, CNRS, UMR 7592, University Paris Diderot, Sorbonne Paris Cité, 75205 Paris, France
| | - François Nédélec
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany.
| | - Julien Dumont
- Institut Jacques Monod, CNRS, UMR 7592, University Paris Diderot, Sorbonne Paris Cité, 75205 Paris, France.
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25
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Oliferenko S. Understanding eukaryotic chromosome segregation from a comparative biology perspective. J Cell Sci 2018; 131:131/14/jcs203653. [PMID: 30030298 DOI: 10.1242/jcs.203653] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
A long-appreciated variation in fundamental cell biological processes between different species is becoming increasingly tractable due to recent breakthroughs in whole-genome analyses and genome editing techniques. However, the bulk of our mechanistic understanding in cell biology continues to come from just a few well-established models. In this Review, I use the highly diverse strategies of chromosome segregation in eukaryotes as an instrument for a more general discussion on phenotypic variation, possible rules underlying its emergence and its utility in understanding conserved functional relationships underlying this process. Such a comparative approach, supported by modern molecular biology tools, might provide a wider, holistic view of biology that is difficult to achieve when concentrating on a single experimental system.
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Affiliation(s)
- Snezhana Oliferenko
- The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK .,Randall Centre for Cell and Molecular Biophysics, New Hunt's House, Guy's Campus, King's College London, London, SE1 1UL, UK
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26
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Heald R, Gibeaux R. Subcellular scaling: does size matter for cell division? Curr Opin Cell Biol 2018; 52:88-95. [PMID: 29501026 PMCID: PMC5988940 DOI: 10.1016/j.ceb.2018.02.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 02/05/2018] [Accepted: 02/13/2018] [Indexed: 12/14/2022]
Abstract
Among different species or cell types, or during early embryonic cell divisions that occur in the absence of cell growth, the size of subcellular structures, including the nucleus, chromosomes, and mitotic spindle, scale with cell size. Maintaining correct subcellular scales is thought to be important for many cellular processes and, in particular, for mitosis. In this review, we provide an update on nuclear and chromosome scaling mechanisms and their significance in metazoans, with a focus on Caenorhabditis elegans, Xenopus and mammalian systems, for which a common role for the Ran (Ras-related nuclear protein)-dependent nuclear transport system has emerged.
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Affiliation(s)
- Rebecca Heald
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA.
| | - Romain Gibeaux
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA.
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27
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Milunovic-Jevtic A, Jevtic P, Levy DL, Gatlin JC. In vivo mitotic spindle scaling can be modulated by changing the levels of a single protein: the microtubule polymerase XMAP215. Mol Biol Cell 2018; 29:1311-1317. [PMID: 29851557 PMCID: PMC5994900 DOI: 10.1091/mbc.e18-01-0011] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
In many organisms, early embryonic development is characterized by a series of reductive cell divisions that result in rapid increases in cell number and concomitant decreases in cell size. Intracellular organelles, such as the nucleus and mitotic spindle, also become progressively smaller during this developmental window, but the molecular and mechanistic underpinnings of these scaling relationships are not fully understood. For the mitotic spindle, changes in cytoplasmic volume are sufficient to account for size scaling during early development in certain organisms. This observation is consistent with models that evoke a limiting component, whereby the smaller absolute number of spindle components in smaller cells limits spindle size. Here we investigate the role of a candidate factor for developmental spindle scaling, the microtubule polymerase XMAP215. Microinjection of additional XMAP215 protein into Xenopus laevis embryos was sufficient to induce the assembly of larger spindles during developmental stages 6.5, 7, and 8, whereas addition of a polymerase-incompetent XMAP215 mutant resulted in a downward shift in the in vivo spindle scaling curve. In sum, these results indicate that even small cells are able to produce larger spindles if microtubule growth rates are increased and suggest that structural components are not limiting.
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Affiliation(s)
- Ana Milunovic-Jevtic
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071.,Molecular and Cellular Life Sciences Program, University of Wyoming, Laramie, WY 82071
| | - Predrag Jevtic
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071.,Molecular and Cellular Life Sciences Program, University of Wyoming, Laramie, WY 82071
| | - Daniel L Levy
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071.,Molecular and Cellular Life Sciences Program, University of Wyoming, Laramie, WY 82071
| | - J C Gatlin
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071.,Molecular and Cellular Life Sciences Program, University of Wyoming, Laramie, WY 82071
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28
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Miettinen TP, Caldez MJ, Kaldis P, Björklund M. Cell size control - a mechanism for maintaining fitness and function. Bioessays 2017; 39. [PMID: 28752618 DOI: 10.1002/bies.201700058] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The maintenance of cell size homeostasis has been studied for years in different cellular systems. With the focus on 'what regulates cell size', the question 'why cell size needs to be maintained' has been largely overlooked. Recent evidence indicates that animal cells exhibit nonlinear cell size dependent growth rates and mitochondrial metabolism, which are maximal in intermediate sized cells within each cell population. Increases in intracellular distances and changes in the relative cell surface area impose biophysical limitations on cells, which can explain why growth and metabolic rates are maximal in a specific cell size range. Consistently, aberrant increases in cell size, for example through polyploidy, are typically disadvantageous to cellular metabolism, fitness and functionality. Accordingly, cellular hypertrophy can potentially predispose to or worsen metabolic diseases. We propose that cell size control may have emerged as a guardian of cellular fitness and metabolic activity.
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Affiliation(s)
- Teemu P Miettinen
- MRC Laboratory for Molecular Cell Biology, University College London, London, UK.,Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Matias J Caldez
- Institute of Molecular and Cell Biology (IMCB), A*STAR (Agency for Science, Technology and Research), Singapore, Singapore.,Department of Biochemistry, National University of Singapore (NUS), Singapore, Singapore
| | - Philipp Kaldis
- Institute of Molecular and Cell Biology (IMCB), A*STAR (Agency for Science, Technology and Research), Singapore, Singapore.,Department of Biochemistry, National University of Singapore (NUS), Singapore, Singapore
| | - Mikael Björklund
- Division of Cell and Developmental Biology, School of Life Sciences, University of Dundee, Dundee, Scotland, UK
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29
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Spencer AK, Schaumberg AJ, Zallen JA. Scaling of cytoskeletal organization with cell size in Drosophila. Mol Biol Cell 2017; 28:1519-1529. [PMID: 28404752 PMCID: PMC5449150 DOI: 10.1091/mbc.e16-10-0691] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 03/31/2017] [Accepted: 04/05/2017] [Indexed: 11/11/2022] Open
Abstract
Actin-rich denticle precursors are regularly distributed in the Drosophila embryo. Cytoskeletal scaling occurs through changes in denticle number and spacing. Denticle spacing scales with cell length over a 10-fold range. Accurate denticle positioning requires the microtubule cytoskeleton. Spatially organized macromolecular complexes are essential for cell and tissue function, but the mechanisms that organize micron-scale structures within cells are not well understood. Microtubule-based structures such as mitotic spindles scale with cell size, but less is known about the scaling of actin structures within cells. Actin-rich denticle precursors cover the ventral surface of the Drosophila embryo and larva and provide templates for cuticular structures involved in larval locomotion. Using quantitative imaging and statistical modeling, we demonstrate that denticle number and spacing scale with cell length over a wide range of cell sizes in embryos and larvae. Denticle number and spacing are reduced under space-limited conditions, and both features robustly scale over a 10-fold increase in cell length during larval growth. We show that the relationship between cell length and denticle spacing can be recapitulated by specific mathematical equations in embryos and larvae and that accurate denticle spacing requires an intact microtubule network and the microtubule minus end–binding protein, Patronin. These results identify a novel mechanism of microtubule-dependent actin scaling that maintains precise patterns of actin organization during tissue growth.
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Affiliation(s)
- Alison K Spencer
- Gerstner Sloan Kettering Graduate School of Biomedical Sciences.,Howard Hughes Medical Institute and Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065
| | - Andrew J Schaumberg
- Weill Cornell Graduate School of Medical Sciences and the Tri-Institutional PhD Program in Computational Biology and Medicine, Memorial Sloan Kettering Cancer Center, New York, NY 10065
| | - Jennifer A Zallen
- Howard Hughes Medical Institute and Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065
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30
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Miettinen TP, Björklund M. Cellular Allometry of Mitochondrial Functionality Establishes the Optimal Cell Size. Dev Cell 2016; 39:370-382. [PMID: 27720611 PMCID: PMC5104693 DOI: 10.1016/j.devcel.2016.09.004] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 06/27/2016] [Accepted: 09/02/2016] [Indexed: 01/31/2023]
Abstract
Eukaryotic cells attempt to maintain an optimal size, resulting in size homeostasis. While cellular content scales isometrically with cell size, allometric laws indicate that metabolism per mass unit should decline with increasing size. Here we use elutriation and single-cell flow cytometry to analyze mitochondrial scaling with cell size. While mitochondrial content increases linearly, mitochondrial membrane potential and oxidative phosphorylation are highest at intermediate cell sizes. Thus, mitochondrial content and functional scaling are uncoupled. The nonlinearity of mitochondrial functionality is cell size, not cell cycle, dependent, and it results in an optimal cell size whereby cellular fitness and proliferative capacity are maximized. While optimal cell size is controlled by growth factor signaling, its establishment and maintenance requires mitochondrial dynamics, which can be controlled by the mevalonate pathway. Thus, optimization of cellular fitness and functionality through mitochondria can explain the requirement for size control, as well as provide means for its maintenance. Mitochondrial functionality is highest in intermediate-sized cells in a population Mitochondrial membrane potential changes with cell size, not cell cycle Evidence for an optimal cell size, whereby functionality and fitness are maximized Mitochondrial dynamics and mevalonate pathway required for the optimal cell size
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Affiliation(s)
- Teemu P Miettinen
- Division of Cell and Developmental Biology, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK; MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, UK; Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Mikael Björklund
- Division of Cell and Developmental Biology, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK.
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31
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Abstract
Cells of a given type maintain a characteristic cell size to function efficiently in their ecological or organismal context. They achieve this through the regulation of growth rates or by actively sensing size and coupling this signal to cell division. We focus this review on potential size-sensing mechanisms, including geometric, external cue, and titration mechanisms. Mechanisms that titrate proteins against DNA are of particular interest because they are consistent with the robust correlation of DNA content and cell size. We review the literature, which suggests that titration mechanisms may underlie cell-size sensing in Xenopus embryos, budding yeast, and Escherichia coli, whereas alternative mechanisms may function in fission yeast.
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Affiliation(s)
- Amanda A Amodeo
- Department of Biology, Stanford University, Stanford, California 94305
| | - Jan M Skotheim
- Department of Biology, Stanford University, Stanford, California 94305
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32
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Levy DL, Heald R. Biological Scaling Problems and Solutions in Amphibians. Cold Spring Harb Perspect Biol 2015; 8:a019166. [PMID: 26261280 DOI: 10.1101/cshperspect.a019166] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Size is a primary feature of biological systems that varies at many levels, from the organism to its constituent cells and subcellular structures. Amphibians populate some of the extremes in biological size and have provided insight into scaling mechanisms, upper and lower size limits, and their physiological significance. Body size variation is a widespread evolutionary tactic among amphibians, with miniaturization frequently correlating with direct development that occurs without a tadpole stage. The large genomes of salamanders lead to large cell sizes that necessitate developmental modification and morphological simplification. Amphibian extremes at the cellular level have provided insight into mechanisms that accommodate cell-size differences. Finally, how organelles scale to cell size between species and during development has been investigated at the molecular level, because subcellular scaling can be recapitulated using Xenopus in vitro systems.
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Affiliation(s)
- Daniel L Levy
- Department of Molecular Biology, University of Wyoming, Laramie, Wyoming 82071
| | - Rebecca Heald
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720
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Abstract
To achieve optimal functionality, plant organs like leaves and petals have to grow to a certain size. Beginning with a limited number of undifferentiated cells, the final size of an organ is attained by a complex interplay of cell proliferation and subsequent cell expansion. Regulatory mechanisms that integrate intrinsic growth signals and environmental cues are required to enable optimal leaf and flower development. This review focuses on plant-specific principles of growth reaching from the cellular to the organ level. The currently known genetic pathways underlying these principles are summarized and network connections are highlighted. Putative non-cell autonomously acting mechanisms that might coordinate plant-cell growth are discussed.
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Affiliation(s)
- Hjördis Czesnick
- Institute for Biochemistry and Biology, University of Potsdam, Potsdam 14476, Germany
| | - Michael Lenhard
- Institute for Biochemistry and Biology, University of Potsdam, Potsdam 14476, Germany
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