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Forget M, Adiba S, De Monte S. Single-cell phenotypic plasticity modulates social behavior in Dictyostelium discoideum. iScience 2023; 26:106783. [PMID: 37235054 PMCID: PMC10206496 DOI: 10.1016/j.isci.2023.106783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 02/09/2023] [Accepted: 04/26/2023] [Indexed: 05/28/2023] Open
Abstract
In Dictyostelium chimeras, "cheaters" are strains that positively bias their contribution to the pool of spores, i.e., the reproductive cells resulting from development. On evolutionary time scales, the selective advantage; thus, gained by cheaters is predicted to undermine collective functions whenever social behaviors are genetically determined. Genotypes; however, are not the sole determinant of spore bias, but the relative role of genetic and plastic differences in evolutionary success is unclear. Here, we study chimeras composed of cells harvested in different phases of population growth. We show that such heterogeneity induces frequency-dependent, plastic variation in spore bias. In genetic chimeras, the magnitude of such variation is not negligible and can even reverse the classification of a strain's social behavior. Our results suggest that differential cell mechanical properties can underpin, through biases emerging during aggregation, a "lottery" in strains' reproductive success that may counter the evolution of cheating.
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Affiliation(s)
- Mathieu Forget
- Institut de Biologie de l’Ecole Normale Supérieure, Département de Biologie, Ecole Normale Supérieure, CNRS, INSERM, PSL Research University, Paris, France
- Department of Evolutionary Theory, Max Planck Institute for Evolutionary Biology, Plőn, Germany
| | - Sandrine Adiba
- Institut de Biologie de l’Ecole Normale Supérieure, Département de Biologie, Ecole Normale Supérieure, CNRS, INSERM, PSL Research University, Paris, France
| | - Silvia De Monte
- Institut de Biologie de l’Ecole Normale Supérieure, Département de Biologie, Ecole Normale Supérieure, CNRS, INSERM, PSL Research University, Paris, France
- Department of Evolutionary Theory, Max Planck Institute for Evolutionary Biology, Plőn, Germany
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2
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Bajgar A, Krejčová G. On the origin of the functional versatility of macrophages. Front Physiol 2023; 14:1128984. [PMID: 36909237 PMCID: PMC9998073 DOI: 10.3389/fphys.2023.1128984] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 02/07/2023] [Indexed: 02/25/2023] Open
Abstract
Macrophages represent the most functionally versatile cells in the animal body. In addition to recognizing and destroying pathogens, macrophages remove senescent and exhausted cells, promote wound healing, and govern tissue and metabolic homeostasis. In addition, many specialized populations of tissue-resident macrophages exhibit highly specialized functions essential for the function of specific organs. Sometimes, however, macrophages cease to perform their protective function and their seemingly incomprehensible response to certain stimuli leads to pathology. In this study, we address the question of the origin of the functional versatility of macrophages. To this end, we have searched for the evolutionary origin of macrophages themselves and for the emergence of their characteristic properties. We hypothesize that many of the characteristic features of proinflammatory macrophages evolved in the unicellular ancestors of animals, and that the functional repertoire of macrophage-like amoebocytes further expanded with the evolution of multicellularity and the increasing complexity of tissues and organ systems. We suggest that the entire repertoire of macrophage functions evolved by repurposing and diversification of basic functions that evolved early in the evolution of metazoans under conditions barely comparable to that in tissues of multicellular organisms. We believe that by applying this perspective, we may find an explanation for the otherwise counterintuitive behavior of macrophages in many human pathologies.
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Affiliation(s)
- Adam Bajgar
- Faculty of Science, Department of Molecular Biology and Genetics, University of South Bohemia, Ceske Budejovice, Czechia.,Biology Centre, Institute of Entomology, Academy of Sciences, Ceske Budejovice, Czechia
| | - Gabriela Krejčová
- Faculty of Science, Department of Molecular Biology and Genetics, University of South Bohemia, Ceske Budejovice, Czechia.,Biology Centre, Institute of Entomology, Academy of Sciences, Ceske Budejovice, Czechia
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3
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Morawska LP, Hernandez-Valdes JA, Kuipers OP. Diversity of bet-hedging strategies in microbial communities-Recent cases and insights. WIREs Mech Dis 2022; 14:e1544. [PMID: 35266649 PMCID: PMC9286555 DOI: 10.1002/wsbm.1544] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 10/05/2021] [Accepted: 10/07/2021] [Indexed: 12/12/2022]
Abstract
Microbial communities are continuously exposed to unpredictable changes in their environment. To thrive in such dynamic habitats, microorganisms have developed the ability to readily switch phenotypes, resulting in a number of differently adapted subpopulations expressing various traits. In evolutionary biology, a particular case of phenotypic heterogeneity that evolved in an unpredictably changing environment has been defined as bet‐hedging. Bet‐hedging is a risk‐spreading strategy where isogenic populations stochastically (randomly) diversify their phenotypes, often resulting in maladapted individuals that suffer lower reproductive success. This fitness trade‐off in a specific environment may have a selective advantage upon the sudden environmental shift. Thus, a bet‐hedging strategy allows populations to persist in very dynamic habitats, but with a particular fitness cost. In recent years, numerous examples of phenotypic heterogeneity in different microorganisms have been observed, some suggesting bet‐hedging. Here, we highlight the latest reports concerning bet‐hedging phenomena in various microorganisms to show how versatile this strategy is within the microbial realms. This article is categorized under:Infectious Diseases > Molecular and Cellular Physiology
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Affiliation(s)
- Luiza P Morawska
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, Groningen, The Netherlands
| | - Jhonatan A Hernandez-Valdes
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, Groningen, The Netherlands
| | - Oscar P Kuipers
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, Groningen, The Netherlands
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4
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Gross JD, Pears CJ. Possible Involvement of the Nutrient and Energy Sensors mTORC1 and AMPK in Cell Fate Diversification in a Non-Metazoan Organism. Front Cell Dev Biol 2021; 9:758317. [PMID: 34820379 PMCID: PMC8606421 DOI: 10.3389/fcell.2021.758317] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 10/19/2021] [Indexed: 11/13/2022] Open
Abstract
mTORC1 and AMPK are mutually antagonistic sensors of nutrient and energy status that have been implicated in many human diseases including cancer, Alzheimer’s disease, obesity and type 2 diabetes. Starved cells of the social amoeba Dictyostelium discoideum aggregate and eventually form fruiting bodies consisting of stalk cells and spores. We focus on how this bifurcation of cell fate is achieved. During growth mTORC1 is highly active and AMPK relatively inactive. Upon starvation, AMPK is activated and mTORC1 inhibited; cell division is arrested and autophagy induced. After aggregation, a minority of the cells (prestalk cells) continue to express much the same set of developmental genes as during aggregation, but the majority (prespore cells) switch to the prespore program. We describe evidence suggesting that overexpressing AMPK increases the proportion of prestalk cells, as does inhibiting mTORC1. Furthermore, stimulating the acidification of intracellular acidic compartments likewise increases the proportion of prestalk cells, while inhibiting acidification favors the spore pathway. We conclude that the choice between the prestalk and the prespore pathways of cell differentiation may depend on the relative strength of the activities of AMPK and mTORC1, and that these may be controlled by the acidity of intracellular acidic compartments/lysosomes (pHv), cells with low pHv compartments having high AMPK activity/low mTORC1 activity, and those with high pHv compartments having high mTORC1/low AMPK activity. Increased insight into the regulation and downstream consequences of this switch should increase our understanding of its potential role in human diseases, and indicate possible therapeutic interventions.
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Affiliation(s)
- Julian D Gross
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Catherine J Pears
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
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5
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Dhakshinamoorthy R, Singh SP. Evolution of Reproductive Division of Labor - Lessons Learned From the Social Amoeba Dictyostelium discoideum During Its Multicellular Development. Front Cell Dev Biol 2021; 9:599525. [PMID: 33748102 PMCID: PMC7969725 DOI: 10.3389/fcell.2021.599525] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 02/12/2021] [Indexed: 11/13/2022] Open
Abstract
The origin of multicellular life from unicellular beings is an epochal step in the evolution of eukaryotes. There are several factors influencing cell fate choices during differentiation and morphogenesis of an organism. Genetic make-up of two cells that unite and fertilize is the key factor to signal the formation of various cell-types in due course of development. Although ploidy of the cell-types determines the genetics of an individual, the role of ploidy in cell fate decisions remains unclear. Dictyostelium serves as a versatile model to study the emergence of multicellular life from unicellular life forms. In this work, we investigate the role played by ploidy status of a cell on cell fate commitments during Dictyostelium development. To answer this question, we created Dictyostelium cells of different ploidy: haploid parents and derived isogenic diploids, allowing them to undergo development. The diploid strains used in this study were generated using parasexual genetics. The ploidy status of the haploids and diploids were confirmed by microscopy, flow cytometry, and karyotyping. Prior to reconstitution, we labeled the cells by two methods. First, intragenic expression of red fluorescent protein (RFP) and second, staining the amoebae with a vital, fluorescent dye carboxyfluorescein succinimidyl ester (CFSE). RFP labeled haploid cells allowed us to track the haploids in the chimeric aggregates, slugs, and fruiting bodies. The CFSE labeling method allowed us to track both the haploids and the diploids in the chimeric developmental structures. Our findings illustrate that the haploids demonstrate sturdy cell fate commitment starting from the aggregation stage. The haploids remain crowded at the aggregation centers of the haploid-diploid chimeric aggregates. At the slug stage haploids are predominantly occupying the slug posterior, and are visible in the spore population in the fruiting bodies. Our findings show that cell fate decisions during D. discoideum development are highly influenced by the ploidy status of a cell, adding a new aspect to already known factors Here, we report that ploidy status of a cell could also play a crucial role in regulating the cell fate commitments.
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Affiliation(s)
- Ranjani Dhakshinamoorthy
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai, India
| | - Shashi P Singh
- Cell Migration and Chemotaxis Group, Cancer Research UK Beatson Institute, Glasgow, United Kingdom
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6
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Trenchard H. Cell pelotons: A model of early evolutionary cell sorting, with application to slime mold Dictyostelium discoideum. J Theor Biol 2019; 469:75-95. [PMID: 30794840 DOI: 10.1016/j.jtbi.2019.02.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2018] [Revised: 01/29/2019] [Accepted: 02/19/2019] [Indexed: 11/19/2022]
Abstract
A theoretical model is presented for early evolutionary cell sorting within cellular aggregates. The model involves an energy-saving mechanism and principles of collective self-organization analogous to those observed in bicycle pelotons (groups of cyclists). The theoretical framework is applied to slime-mold slugs (Dictyostelium discoideum) and incorporated into a computer simulation which demonstrates principally the sorting of cells between the anterior and posterior slug regions. The simulation relies on an existing simulation of bicycle peloton dynamics which is modified to incorporate a limited range of cell metabolic capacities among heterogeneous cells, along with a tunable energy-expenditure parameter, referred to as an "output-level" or "starvation-level" to reflect diminishing energetic supply. Proto-cellular dynamics are modeled for three output phases: "active", "suffering", and "dying or dead." Adjusting the starvation parameter causes cell differentiation and sorting into sub-groups within the cellular aggregate. Tuning of the starvation parameter demonstrates how weak or expired cells shuffle backward within the cellular aggregate.
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Affiliation(s)
- Hugh Trenchard
- Independent Researcher, 805 647 Michigan Street, Victoria, BC V8V 1S9, Canada.
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7
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Garcia T, Doulcier G, De Monte S. The evolution of adhesiveness as a social adaptation. eLife 2015; 4:e08595. [PMID: 26613415 PMCID: PMC4775229 DOI: 10.7554/elife.08595] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 11/26/2015] [Indexed: 12/31/2022] Open
Abstract
Cellular adhesion is a key ingredient to sustain collective functions of microbial aggregates. Here, we investigate the evolutionary origins of adhesion and the emergence of groups of genealogically unrelated cells with a game-theoretical model. The considered adhesiveness trait is costly, continuous and affects both group formation and group-derived benefits. The formalism of adaptive dynamics reveals two evolutionary stable strategies, at each extreme on the axis of adhesiveness. We show that cohesive groups can evolve by small mutational steps, provided the population is already endowed with a minimum adhesiveness level. Assortment between more adhesive types, and in particular differential propensities to leave a fraction of individuals ungrouped at the end of the aggregation process, can compensate for the cost of increased adhesiveness. We also discuss the change in the social nature of more adhesive mutations along evolutionary trajectories, and find that altruism arises before directly beneficial behavior, despite being the most challenging form of cooperation.
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Affiliation(s)
- Thomas Garcia
- Institut d'écologie et des sciences de l'environnement, Université Pierre et Marie Curie, Paris, France
| | - Guilhem Doulcier
- Institut de Biologie de l’École Normale Supérieure, École Normale Supérieure, PSL Research University, Paris, France
| | - Silvia De Monte
- Institut de Biologie de l’École Normale Supérieure, École Normale Supérieure, PSL Research University, Paris, France
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8
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Pfeuty B. Neuronal specification exploits the inherent flexibility of cell-cycle gap phases. NEUROGENESIS 2015; 2:e1095694. [PMID: 27606329 PMCID: PMC4973608 DOI: 10.1080/23262133.2015.1095694] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Revised: 06/30/2015] [Accepted: 09/14/2015] [Indexed: 12/26/2022]
Abstract
Starting from pluripotent stem cells that virtually proliferate indefinitely, the orderly emergence during organogenesis of lineage-restricted cell types exhibiting a decreased proliferative capacity concurrently with an increasing range of differentiation traits implies the occurrence of a stringent spatiotemporal coupling between cell-cycle progression and cell differentiation. A recent computational modeling study has explored in the context of neurogenesis whether and how the peculiar pattern of connections among the proneural Neurog2 factor, the Hes1 Notch effector and antagonistically-acting G1-phase regulators would be instrumental in this event. This study highlighted that the strong opposition to G1/S transit imposed by accumulating Neurog2 and CKI enables a sensitive control of G1-phase lengthening and terminal differentiation to occur concomitantly with late-G1 exit. Contrastingly, Hes1 promotes early-G1 cell-cycle arrest and its cell-autonomous oscillations combined with a lateral inhibition mechanism help maintain a labile proliferation state in dynamic balance with diverse cell-fate outputs, thereby, offering cells the choice to either keep self-renewing or differentiate into distinct cell types. These results, discussed in connection with Ascl1-dependent neural differentiation, suggest that developmental fate decisions exploit the inherent flexibility of cell-cycle gap phases to generate diversity by selecting subtly-differing patterns of connections among components of the cell-cycle machinery and differentiation pathways.
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Affiliation(s)
- Benjamin Pfeuty
- Laboratoire de Physique des Lasers Atomes et Molécules; CNRS; Université de Lille ; Villeneuve d'Ascq, France
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9
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Root of Dictyostelia based on 213 universal proteins. Mol Phylogenet Evol 2015; 92:53-62. [PMID: 26048704 DOI: 10.1016/j.ympev.2015.05.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Revised: 05/18/2015] [Accepted: 05/19/2015] [Indexed: 01/03/2023]
Abstract
Dictyostelia are common soil microbes that can aggregate when starved to form multicellular fruiting bodies, a characteristic that has also led to their long history of study and widespread use as model systems. Ribosomal RNA phylogeny of Dictyostelia identified four major divisions (Groups 1-4), none of which correspond to traditional genera. Group 1 was also tentatively identified as sister lineage to the other three Groups, although not consistently or with strong support. We tested the dictyostelid root using universal protein-coding genes identified by exhaustive comparison of six completely sequenced dictyostelid genomes, which include representatives of all four major molecular Groups. A set of 213 genes are low-copy number in all genomes, present in at least one amoebozoan outgroup taxon (Acanthamoeba castellanii or Physarum polycephalum), and phylogenetically congruent. Phylogenetic analysis of a concatenation of the deduced protein sequences produces a single topology dividing Dictyostelia into two major divisions: Groups 1+2 and Groups 3+4. All clades in the tree are fully supported by maximum likelihood and Bayesian inference, and all alternative roots are unambiguously rejected by the approximately unbiased (AU) test. The 1+2, 3+4 root is also fully supported even after deleting clusters with strong individual support for this root, or concatenating all clusters with low support for alternative roots. The 213 putatively ancestral amoebozoan proteins encode a wide variety of functions including 21 KOG categories out of a total of 25. These comprehensive analyses and consistent results indicate that it is time for full taxonomic revision of Dictyostelia, which will also enable more effective exploitation of its unique potential as an evolutionary model system.
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10
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Precarious development: the uncertain social life of cellular slime molds. Proc Natl Acad Sci U S A 2015; 112:2639-40. [PMID: 25713343 DOI: 10.1073/pnas.1500708112] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
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11
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DeBord JD, Smith DF, Anderton CR, Heeren RMA, Paša-Tolić L, Gomer RH, Fernandez-Lima FA. Secondary ion mass spectrometry imaging of Dictyostelium discoideum aggregation streams. PLoS One 2014; 9:e99319. [PMID: 24911189 PMCID: PMC4049834 DOI: 10.1371/journal.pone.0099319] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 05/13/2014] [Indexed: 11/23/2022] Open
Abstract
High resolution imaging mass spectrometry could become a valuable tool for cell and developmental biology, but both, high spatial and mass spectral resolution are needed to enable this. In this report, we employed Bi3 bombardment time-of-flight (Bi3 ToF-SIMS) and C60 bombardment Fourier transform ion cyclotron resonance secondary ion mass spectrometry (C60 FTICR-SIMS) to image Dictyostelium discoideum aggregation streams. Nearly 300 lipid species were identified from the aggregation streams. High resolution mass spectrometry imaging (FTICR-SIMS) enabled the generation of multiple molecular ion maps at the nominal mass level and provided good coverage for fatty acyls, prenol lipids, and sterol lipids. The comparison of Bi3 ToF-SIMS and C60 FTICR-SIMS suggested that while the first provides fast, high spatial resolution molecular ion images, the chemical complexity of biological samples warrants the use of high resolution analyzers for accurate ion identification.
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Affiliation(s)
- John Daniel DeBord
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida, United States of America
| | - Donald F. Smith
- FOM Institute AMOLF, Science Park 104, Amsterdam, The Netherlands
| | - Christopher R. Anderton
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington, United States of America
| | - Ron M. A. Heeren
- FOM Institute AMOLF, Science Park 104, Amsterdam, The Netherlands
| | - Ljiljana Paša-Tolić
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington, United States of America
| | - Richard H. Gomer
- Department of Biology, Texas A&M University, College Station, Texas, United States of America
| | - Francisco A. Fernandez-Lima
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida, United States of America
- * E-mail:
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12
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O'Day DH, Budniak A. Nucleocytoplasmic protein translocation during mitosis in the social amoebozoan Dictyostelium discoideum. Biol Rev Camb Philos Soc 2014; 90:126-41. [PMID: 24618050 DOI: 10.1111/brv.12100] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Revised: 02/10/2014] [Accepted: 02/13/2014] [Indexed: 01/03/2023]
Abstract
Mitosis is a fundamental and essential life process. It underlies the duplication and survival of all cells and, as a result, all eukaryotic organisms. Since uncontrolled mitosis is a dreaded component of many cancers, a full understanding of the process is critical. Evolution has led to the existence of three types of mitosis: closed, open, and semi-open. The significance of these different mitotic species, how they can lead to a full understanding of the critical events that underlie the asexual duplication of all cells, and how they may generate new insights into controlling unregulated cell division remains to be determined. The eukaryotic microbe Dictyostelium discoideum has proved to be a valuable biomedical model organism. While it appears to utilize closed mitosis, a review of the literature suggests that it possesses a form of mitosis that lies in the middle between truly open and fully closed mitosis-it utilizes a form of semi-open mitosis. Here, the nucleocytoplasmic translocation patterns of the proteins that have been studied during mitosis in the social amoebozoan D. discoideum are detailed followed by a discussion of how some of them provide support for the hypothesis of semi-open mitosis.
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Affiliation(s)
- Danton H O'Day
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road N., Mississauga, Ontario, L5L 1C6, Canada; Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, Ontario, M5S 3G5, Canada
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13
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Huber RJ. The cyclin-dependent kinase family in the social amoebozoan Dictyostelium discoideum. Cell Mol Life Sci 2014; 71:629-39. [PMID: 23974243 PMCID: PMC11113532 DOI: 10.1007/s00018-013-1449-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Revised: 07/24/2013] [Accepted: 08/05/2013] [Indexed: 10/26/2022]
Abstract
Cyclin-dependent kinases (Cdk) are a family of serine/threonine protein kinases that regulate eukaryotic cell cycle progression. Their ability to modulate the cell cycle has made them an attractive target for anti-cancer therapies. Cdk protein function has been studied in a variety of Eukaryotes ranging from yeast to humans. In the social amoebozoan Dictyostelium discoideum, several homologues of mammalian Cdks have been identified and characterized. The life cycle of this model organism is comprised of a feeding stage where single cells grow and divide mitotically as they feed on their bacterial food source and a multicellular developmental stage that is induced by starvation. Thus it is a valuable system for studying a variety of cellular and developmental processes. In this review I summarize the current knowledge of the Cdk protein family in Dictyostelium by highlighting the research efforts focused on the characterization of Cdk1, Cdk5, and Cdk8 in this model Eukaryote. Accumulated evidence indicates that each protein performs distinct functions during the Dictyostelium life cycle with Cdk1 being required for growth and Cdk5 and Cdk8 being required for processes that occur during development. Recent studies have shown that Dictyostelium Cdk5 shares attributes with mammalian Cdk5 and that the mammalian Cdk inhibitor roscovitine can be used to inhibit Cdk5 activity in Dictyostelium. Together, these results show that Dictyostelium can be used as a model system for studying Cdk protein function.
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Affiliation(s)
- Robert J Huber
- Center for Human Genetic Research, Massachusetts General Hospital, Harvard Medical School, Richard B. Simches Research Center, 185 Cambridge Street, Boston, MA, 02114, USA,
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14
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Pfeuty B, Kaneko K. Reliable binary cell-fate decisions based on oscillations. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 89:022707. [PMID: 25353509 DOI: 10.1103/physreve.89.022707] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Indexed: 06/04/2023]
Abstract
Biological systems have often to perform binary decisions under highly dynamic and noisy environments, such as during cell-fate determination. These decisions can be implemented by two main bifurcation mechanisms based on the transitions from either monostability or oscillation to bistability. We compare these two mechanisms by using stochastic models with time-varying fields and by establishing asymptotic formulas for the choice probabilities. Different scaling laws for decision sensitivity with respect to noise strength and signal timescale are obtained, supporting a role for oscillatory dynamics in performing noise-robust and temporally tunable binary decision-making. This result provides a rationale for recent experimental evidences showing that oscillatory expression of proteins often precedes binary cell-fate decisions.
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Affiliation(s)
- B Pfeuty
- Laboratoire de Physique des Lasers, Atomes, et Molécules, CNRS, UMR 8523, Université Lille 1, F-59655 Villeneuve d'Ascq, France
| | - K Kaneko
- Graduate School of Arts and Sciences, The University of Tokyo, Komaba, Meguro-ku, Tokyo 153-8902, Japan
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15
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Abstract
Much of our knowledge of molecular cellular functions is based on studies with a few number of model organisms that were established during the last 50 years. The social amoeba Dictyostelium discoideum is one such model, and has been particularly useful for the study of cell motility, chemotaxis, phagocytosis, endocytic vesicle traffic, cell adhesion, pattern formation, caspase-independent cell death, and, more recently, autophagy and social evolution. As nonmammalian model of human diseases D. discoideum is a newcomer, yet it has proven to be a powerful genetic and cellular model for investigating host-pathogen interactions and microbial infections, for mitochondrial diseases, and for pharmacogenetic studies. The D. discoideum genome harbors several homologs of human genes responsible for a variety of diseases, -including Chediak-Higashi syndrome, lissencephaly, mucolipidosis, Huntington disease, IBMPFD, and Shwachman-Diamond syndrome. A few genes have already been studied, providing new insights on the mechanism of action of the encoded proteins and in some cases on the defect underlying the disease. The opportunities offered by the organism and its place among the nonmammalian models for human diseases will be discussed.
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Affiliation(s)
- Salvatore Bozzaro
- Department of Clinical and Biological Sciences, University of Turin, Orbassano, Turin, Italy.
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16
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Evolution and diversity of dictyostelid social amoebae. Protist 2011; 163:327-43. [PMID: 22209334 DOI: 10.1016/j.protis.2011.09.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2011] [Revised: 09/08/2011] [Accepted: 09/18/2011] [Indexed: 11/23/2022]
Abstract
Dictyostelid social amoebae are a large and ancient group of soil microbes with an unusual multicellular stage in their life cycle. Taxonomically, they belong to the eukaryotic supergroup Amoebozoa, the sister group to Opisthokonta (animals + fungi). Roughly half of the ~150 known dictyostelid species were discovered during the last five years and probably many more remain to be found. The traditional classification system of Dictyostelia was completely overturned by cladistic analyses and molecular phylogenies of the past six years. As a result, it now appears that, instead of three major divisions there are eight, none of which correspond to traditional higher-level taxa. In addition to the widely studied Dictyostelium discoideum, there are now efforts to develop model organisms and complete genome sequences for each major group. Thus Dictyostelia is becoming an excellent model for both practical, medically related research and for studying basic principles in cell-cell communication and developmental evolution. In this review we summarize the latest information about their life cycle, taxonomy, evolutionary history, genome projects and practical importance.
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Strassmann JE, Queller DC. Evolution of cooperation and control of cheating in a social microbe. Proc Natl Acad Sci U S A 2011; 108 Suppl 2:10855-62. [PMID: 21690338 PMCID: PMC3131822 DOI: 10.1073/pnas.1102451108] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Much of what we know about the evolution of altruism comes from animals. Here, we show that studying a microbe has yielded unique insights, particularly in understanding how social cheaters are controlled. The social stage of Dictylostelium discoideum occurs when the amoebae run out of their bacterial prey and aggregate into a multicellular, motile slug. This slug forms a fruiting body in which about a fifth of cells die to form a stalk that supports the remaining cells as they form hardy dispersal-ready spores. Because this social stage forms from aggregation, it is analogous to a social group, or a chimeric multicellular organism, and is vulnerable to internal conflict. Advances in cell labeling, microscopy, single-gene knockouts, and genomics, as well as the results of decades of study of D. discoideum as a model for development, allow us to explore the genetic basis of social contests and control of cheaters in unprecedented detail. Cheaters are limited from exploiting other clones by high relatedness, kin discrimination, pleiotropy, noble resistance, and lottery-like role assignment. The active nature of these limits is reflected in the elevated rates of change in social genes compared with nonsocial genes. Despite control of cheaters, some conflict is still expressed in chimeras, with slower movement of slugs, slightly decreased investment in stalk compared with spore cells, and differential contributions to stalk and spores. D. discoideum is rapidly becoming a model system of choice for molecular studies of social evolution.
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Affiliation(s)
- Joan E Strassmann
- Ecology and Evolutionary Biology, Rice University, Houston, TX 77005, USA.
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