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Walker LM, Sherpa RN, Ivaturi S, Brock DA, Larsen TJ, Walker JR, Strassmann JE, Queller DC. Parallel evolution of the G protein-coupled receptor GrlG and the loss of fruiting body formation in the social amoeba Dictyostelium discoideum evolved under low relatedness. G3 (BETHESDA, MD.) 2023; 14:jkad235. [PMID: 37832511 PMCID: PMC10755179 DOI: 10.1093/g3journal/jkad235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 07/25/2023] [Accepted: 09/27/2023] [Indexed: 10/15/2023]
Abstract
Aggregative multicellularity relies on cooperation among formerly independent cells to form a multicellular body. Previous work with Dictyostelium discoideum showed that experimental evolution under low relatedness profoundly decreased cooperation, as indicated by the loss of fruiting body formation in many clones and an increase of cheaters that contribute proportionally more to spores than to the dead stalk. Using whole-genome sequencing and variant analysis of these lines, we identified 38 single nucleotide polymorphisms in 29 genes. Each gene had 1 variant except for grlG (encoding a G protein-coupled receptor), which had 10 unique SNPs and 5 structural variants. Variants in the 5' half of grlG-the region encoding the signal peptide and the extracellular binding domain-were significantly associated with the loss of fruiting body formation; the association was not significant in the 3' half of the gene. These results suggest that the loss of grlG was adaptive under low relatedness and that at least the 5' half of the gene is important for cooperation and multicellular development. This is surprising given some previous evidence that grlG encodes a folate receptor involved in predation, which occurs only during the single-celled stage. However, non-fruiting mutants showed little increase in a parallel evolution experiment where the multicellular stage was prevented from happening. This shows that non-fruiting mutants are not generally selected by any predation advantage but rather by something-likely cheating-during the multicellular stage.
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Affiliation(s)
- Laura M Walker
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Rintsen N Sherpa
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Sindhuri Ivaturi
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Debra A Brock
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Tyler J Larsen
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Jason R Walker
- McDonnell Genome Institute, Washington University School of Medicine, St. Louis, MO 63130, USA
| | - Joan E Strassmann
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - David C Queller
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, USA
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2
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Kirolos SA, Gomer RH. A chemorepellent inhibits local Ras activation to inhibit pseudopod formation to bias cell movement away from the chemorepellent. Mol Biol Cell 2021; 33:ar9. [PMID: 34788129 PMCID: PMC8886819 DOI: 10.1091/mbc.e20-10-0656] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The ability of cells to sense chemical gradients is essential during development, morphogenesis, and immune responses. Although much is known about chemoattraction, chemorepulsion remains poorly understood. Proliferating Dictyostelium cells secrete a chemorepellent protein called AprA. AprA prevents pseudopod formation at the region of the cell closest to the source of AprA, causing the random movement of cells to be biased away from the AprA. Activation of Ras proteins in a localized sector of a cell cortex helps to induce pseudopod formation, and Ras proteins are needed for AprA chemorepulsion. Here we show that AprA locally inhibits Ras cortical activation through the G protein–coupled receptor GrlH, the G protein subunits Gβ and Gα8, Ras protein RasG, protein kinase B, the p21-activated kinase PakD, and the extracellular signal–regulated kinase Erk1. Diffusion calculations and experiments indicate that in a colony of cells, high extracellular concentrations of AprA in the center can globally inhibit Ras activation, while a gradient of AprA that naturally forms at the edge of the colony allows cells to activate Ras at sectors of the cell other than the sector of the cell closest to the center of the colony, effectively inducing both repulsion from the colony and cell differentiation. Together, these results suggest that a pathway that inhibits local Ras activation can mediate chemorepulsion.
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Affiliation(s)
- Sara A Kirolos
- Department of Biology, Texas A&M University, 301 Old Main Drive, College Station, Texas, 77843-3474 USA
| | - Richard H Gomer
- Department of Biology, Texas A&M University, 301 Old Main Drive, College Station, Texas, 77843-3474 USA
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3
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Filić V, Mijanović L, Putar D, Talajić A, Ćetković H, Weber I. Regulation of the Actin Cytoskeleton via Rho GTPase Signalling in Dictyostelium and Mammalian Cells: A Parallel Slalom. Cells 2021; 10:1592. [PMID: 34202767 PMCID: PMC8305917 DOI: 10.3390/cells10071592] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 06/16/2021] [Accepted: 06/16/2021] [Indexed: 01/15/2023] Open
Abstract
Both Dictyostelium amoebae and mammalian cells are endowed with an elaborate actin cytoskeleton that enables them to perform a multitude of tasks essential for survival. Although these organisms diverged more than a billion years ago, their cells share the capability of chemotactic migration, large-scale endocytosis, binary division effected by actomyosin contraction, and various types of adhesions to other cells and to the extracellular environment. The composition and dynamics of the transient actin-based structures that are engaged in these processes are also astonishingly similar in these evolutionary distant organisms. The question arises whether this remarkable resemblance in the cellular motility hardware is accompanied by a similar correspondence in matching software, the signalling networks that govern the assembly of the actin cytoskeleton. Small GTPases from the Rho family play pivotal roles in the control of the actin cytoskeleton dynamics. Indicatively, Dictyostelium matches mammals in the number of these proteins. We give an overview of the Rho signalling pathways that regulate the actin dynamics in Dictyostelium and compare them with similar signalling networks in mammals. We also provide a phylogeny of Rho GTPases in Amoebozoa, which shows a variability of the Rho inventories across different clades found also in Metazoa.
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Affiliation(s)
- Vedrana Filić
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička 54, HR-10000 Zagreb, Croatia; (L.M.); (D.P.); (A.T.); (H.Ć.)
| | | | | | | | | | - Igor Weber
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička 54, HR-10000 Zagreb, Croatia; (L.M.); (D.P.); (A.T.); (H.Ć.)
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4
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Ohtsuka D, Ota N, Amaya S, Matsuoka S, Tanaka Y, Ueda M. A sub-population of Dictyostelium discoideum cells shows extremely high sensitivity to cAMP for directional migration. Biochem Biophys Res Commun 2021; 554:131-137. [PMID: 33784508 DOI: 10.1016/j.bbrc.2021.03.095] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 03/17/2021] [Indexed: 01/26/2023]
Abstract
The chemotaxis of Dictysotelium discoideum cells in response to a chemical gradient of cyclic adenosine 3',5'-monophosphate (cAMP) was studied using a newly designed microfluidic device. The device consists of 800 cell-sized channels in parallel, each 4 μm wide, 5 μm high, and 100 μm long, allowing us to prepare the same chemical gradient in all channels and observe the motility of 500-1000 individual cells simultaneously. The percentage of cells that exhibited directed migration was determined for various cAMP concentrations ranging from 0.1 pM to 10 μM. The results show that chemotaxis was highest at 100 nM cAMP, consistent with previous observations. At concentrations as low as 10 pM, about 16% of cells still exhibited chemotaxis, suggesting that the receptor occupancy of only 6 cAMP molecules/cell can induce chemotaxis in very sensitive cells. At 100 pM cAMP, chemotaxis was suppressed due to the self-production and secretion of intracellular cAMP induced by extracellular cAMP. Overall, systematic observations of a large number of individual cells under the same chemical gradients revealed the heterogeneity of chemotaxis responses in a genetically homogeneous cell population, especially the existence of a sub-population with extremely high sensitivity for chemotaxis.
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Affiliation(s)
- Daisuke Ohtsuka
- Laboratory of Single Molecule Biology, Graduate School of Science and Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Nobutoshi Ota
- Laboratory for Integrated Biodevice, Center for Biosystems Dynamics Research (BDR), RIKEN, 1-3 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Satoshi Amaya
- Laboratory for Integrated Biodevice, Center for Biosystems Dynamics Research (BDR), RIKEN, 1-3 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Satomi Matsuoka
- Laboratory of Single Molecule Biology, Graduate School of Science and Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka, 565-0871, Japan; Laboratory for Cell Signaling Dynamics, BDR, RIKEN, Suita, Osaka, 565-0871, Japan; PRESTO, JST, Suita, Osaka, 565-0871, Japan.
| | - Yo Tanaka
- Laboratory for Integrated Biodevice, Center for Biosystems Dynamics Research (BDR), RIKEN, 1-3 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Masahiro Ueda
- Laboratory of Single Molecule Biology, Graduate School of Science and Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka, 565-0871, Japan; Laboratory for Cell Signaling Dynamics, BDR, RIKEN, Suita, Osaka, 565-0871, Japan.
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Eckstein TF, Vidal-Henriquez E, Bae AJ, Gholami A. Spatial heterogeneities shape the collective behavior of signaling amoeboid cells. Sci Signal 2020; 13:13/655/eaaz3975. [PMID: 33109747 DOI: 10.1126/scisignal.aaz3975] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
In its natural habitat in the forest soil, the cellular slime mold Dictyostelium discoideum is exposed to obstacles. Starving Dictyostelium cells secrete cAMP, which is the key extracellular signaling molecule that promotes the aggregation process required for their long-term survival. Here, we investigated the influence of environmental inhomogeneities on the signaling and pattern formation of Dictyostelium cells. We present experimental data and numerical simulations on the pattern formation of signaling Dictyostelium cells in the presence of periodic arrays of millimeter-sized pillars. We observed concentric cAMP waves that initiated almost synchronously at the pillars and propagated outward. In response to these circular waves, the Dictyostelium cells streamed toward the pillars, forming aggregates arranged in patterns that reflected the periodicity of the lattice of pillars. Our results suggest that, in nature, the excitability threshold and synchronization level of the cells are two key parameters that control the nature of the interaction between cells and spatial heterogeneities in their environment.
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Affiliation(s)
- Torsten F Eckstein
- Max Planck Institute for Dynamics and Self-Organization, Am Faßberg 17, 37077 Göttingen, Germany
| | | | - Albert J Bae
- Max Planck Institute for Dynamics and Self-Organization, Am Faßberg 17, 37077 Göttingen, Germany
| | - Azam Gholami
- Max Planck Institute for Dynamics and Self-Organization, Am Faßberg 17, 37077 Göttingen, Germany.
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Perrin AJ, Patel A, Flueck C, Blackman MJ, Baker DA. cAMP signalling and its role in host cell invasion by malaria parasites. Curr Opin Microbiol 2020; 58:69-74. [PMID: 33032143 DOI: 10.1016/j.mib.2020.09.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 09/08/2020] [Indexed: 02/07/2023]
Abstract
Cyclic adenosine monophosphate (cAMP) is an important signalling molecule across evolution, but until recently there was little information on its role in malaria parasites. Advances in gene editing - in particular conditional genetic approaches and mass spectrometry have paved the way for characterisation of the key components of the cAMP signalling pathway in malaria parasites. This has revealed that cAMP signalling plays a critical role in invasion of host red blood cells by Plasmodium falciparum merozoites through regulating the phosphorylation of key parasite proteins by the cAMP-dependent protein kinase (PKA). These insights will help us to investigate parasite cAMP signalling as a target for novel antimalarial drugs.
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Affiliation(s)
- Abigail J Perrin
- Malaria Biochemistry Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Avnish Patel
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Christian Flueck
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Michael J Blackman
- Malaria Biochemistry Laboratory, The Francis Crick Institute, London, United Kingdom; Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - David A Baker
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom.
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Kumar R, Maurya R, Saran S. Investigating the Role of Translationally Control Tumor Protein in Growth, Development and Differentiation of Dictyostelium discoideum. Front Cell Dev Biol 2020; 8:742. [PMID: 32850852 PMCID: PMC7426469 DOI: 10.3389/fcell.2020.00742] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 07/16/2020] [Indexed: 12/31/2022] Open
Abstract
Translationally controlled tumor protein (TCTP) is a multifunctional protein implicated in various types of cellular processes involving growth and development of an organism. Here, we identified tctp gene in Dictyostelium discoideum and unraveled its function. The sequence analysis of D. discoideum TCTP (DdTCTP) showed its conservation among eukaryotes. Transcript of DdTCTP was highly expressed at the initial time points of development and protein is localized both in the cytoplasm and nucleus. Disruption of tctp was achieved by BSR cassette using double homologous recombination method. Abrogation of tctp resulted in reduced cell proliferation but increased cell size. Additionally, development was delayed by 4 h wherein small-sized aggregates and fruiting bodies were produced by tctp– cells while larger aggregates and fruiting bodies were produced by tctpOE cells concordant with the fact that TCTP regulates prestalk/prespore ratio and cell-type differentiation. tctp– cells produced round spores with reduced viability and stalk cells are arranged in septate pattern as compared to polyhedral manner of wild type. Abrogation of tctp resulted in aberrant localization of cell type specific markers and show low proclivity toward prespore/spore region, in presence of wild type cells.
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Affiliation(s)
- Rakesh Kumar
- Cell and Developmental Biology Lab, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Ranjana Maurya
- Cell and Developmental Biology Lab, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Shweta Saran
- Cell and Developmental Biology Lab, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
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8
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Hillmann F, Forbes G, Novohradská S, Ferling I, Riege K, Groth M, Westermann M, Marz M, Spaller T, Winckler T, Schaap P, Glöckner G. Multiple Roots of Fruiting Body Formation in Amoebozoa. Genome Biol Evol 2018; 10:591-606. [PMID: 29378020 PMCID: PMC5804921 DOI: 10.1093/gbe/evy011] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/11/2018] [Indexed: 02/03/2023] Open
Abstract
Establishment of multicellularity represents a major transition in eukaryote evolution. A subgroup of Amoebozoa, the dictyosteliids, has evolved a relatively simple aggregative multicellular stage resulting in a fruiting body supported by a stalk. Protosteloid amoeba, which are scattered throughout the amoebozoan tree, differ by producing only one or few single stalked spores. Thus, one obvious difference in the developmental cycle of protosteliids and dictyosteliids seems to be the establishment of multicellularity. To separate spore development from multicellular interactions, we compared the genome and transcriptome of a Protostelium species (Protostelium aurantium var. fungivorum) with those of social and solitary members of the Amoebozoa. During fruiting body formation nearly 4,000 genes, corresponding to specific pathways required for differentiation processes, are upregulated. A comparison with genes involved in the development of dictyosteliids revealed conservation of >500 genes, but most of them are also present in Acanthamoeba castellanii for which fruiting bodies have not been documented. Moreover, expression regulation of those genes differs between P. aurantium and Dictyostelium discoideum. Within Amoebozoa differentiation to fruiting bodies is common, but our current genome analysis suggests that protosteliids and dictyosteliids used different routes to achieve this. Most remarkable is both the large repertoire and diversity between species in genes that mediate environmental sensing and signal processing. This likely reflects an immense adaptability of the single cell stage to varying environmental conditions. We surmise that this signaling repertoire provided sufficient building blocks to accommodate the relatively simple demands for cell-cell communication in the early multicellular forms.
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Affiliation(s)
- Falk Hillmann
- Junior Research Group Evolution of Microbial Interaction, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knöll Institute (HKI), Jena, Germany
| | - Gillian Forbes
- Division of Cell and Developmental Biology, School of Life Sciences, University of Dundee, United Kingdom
| | - Silvia Novohradská
- Junior Research Group Evolution of Microbial Interaction, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knöll Institute (HKI), Jena, Germany
| | - Iuliia Ferling
- Junior Research Group Evolution of Microbial Interaction, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knöll Institute (HKI), Jena, Germany
| | - Konstantin Riege
- Bioinformatics/High Throughput Analysis, Friedrich Schiller University Jena, Germany
| | - Marco Groth
- CF DNA-Sequencing, Leibniz Institute on Aging Research, Jena, Germany
| | | | - Manja Marz
- Bioinformatics/High Throughput Analysis, Friedrich Schiller University Jena, Germany
| | - Thomas Spaller
- Pharmaceutical Biology, Institute of Pharmacy, Friedrich Schiller University Jena, Germany
| | - Thomas Winckler
- Pharmaceutical Biology, Institute of Pharmacy, Friedrich Schiller University Jena, Germany
| | - Pauline Schaap
- Division of Cell and Developmental Biology, School of Life Sciences, University of Dundee, United Kingdom
| | - Gernot Glöckner
- Institute of Biochemistry I, Medical Faculty, University of Cologne, Germany
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Tanwar M, Khera L, Haokip N, Kaul R, Naorem A, Kateriya S. Modulation of cyclic nucleotide-mediated cellular signaling and gene expression using photoactivated adenylyl cyclase as an optogenetic tool. Sci Rep 2017; 7:12048. [PMID: 28935957 PMCID: PMC5608697 DOI: 10.1038/s41598-017-12162-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 09/01/2017] [Indexed: 11/09/2022] Open
Abstract
Cyclic nucleotide signaling pathway plays a significant role in various biological processes such as cell growth, transcription, inflammation, in microbial pathogenesis, etc. Modulation of cyclic nucleotide levels by optogenetic tools has overcome certain limitations of studying transduction cascade by pharmacological agents and has allowed several ways to modulate biological processes in a spatiotemporal manner. Here, we have shown the optogenetic modulation of the cyclooxygenase 2 (Cox-2) gene expression and their downstream effector molecule (PGE2) in HEK-293T cells and the development process of Dictyostelium discoideum via modulating the cyclic nucleotide (cAMP) signaling pathway utilizing photoactivated adenylyl cyclases (PACs) as an optogenetic tool. Light-induced activation of PACs in HEK-293T cells increases the cAMP level that leads to activation of cAMP response element-binding protein (CREB) transcription factor and further upregulates downstream Cox-2 gene expression and their downstream effector molecule prostaglandin E2. In D. discoideum, the light-regulated increase in cAMP level affects the starvation-induced developmental process. These PACs could modulate the cAMP levels in a light-dependent manner and have a potential to control gene expression and their downstream effector molecules with varying magnitude. It would enable one to utilize PAC as a tool to decipher cyclic nucleotide mediated signaling pathway regulations and their mechanism.
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Affiliation(s)
- Meenakshi Tanwar
- Department of Biochemistry, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India
| | - Lohit Khera
- Department of Microbiology, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India
| | - Nemneineng Haokip
- Department of Genetics, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India
| | - Rajeev Kaul
- Department of Microbiology, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India
| | - Aruna Naorem
- Department of Genetics, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India
| | - Suneel Kateriya
- Department of Biochemistry, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India. .,School of Biotechnology, Jawaharlal Nehru University, New Delhi, 110067, India.
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Lee HM, Kim JS, Kang SO. Glutathione upregulates cAMP signalling via G protein alpha 2 during the development of Dictyostelium discoideum. FEBS Lett 2016; 590:4361-4371. [PMID: 27718249 DOI: 10.1002/1873-3468.12453] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 09/12/2016] [Accepted: 09/23/2016] [Indexed: 11/06/2022]
Abstract
Despite the importance of glutathione in Dictyostelium, the role of glutathione synthetase (gshB/GSS) has not been clearly investigated. In this study, we observed that increasing glutathione content by constitutive expression of gshB leads to mound-arrest and defects in 3',5'-cyclic adenosine monophosphate (cAMP)-mediated aggregation and developmental gene expression. The overexpression of gpaB encoding G protein alpha 2 (Gα2), an essential component of the cAMP signalling pathway, results in a phenotype similar to that caused by gshB overexpression, whereas gpaB knockdown in gshB-overexpressing cells partially rescues the above-mentioned phenotypic defects. Furthermore, Gα2 is highly enriched at the plasma membrane of gshB-overexpressing cells compared to wild-type cells. Therefore, our findings suggest that glutathione upregulates cAMP signalling via Gα2 modulation during Dictyostelium development.
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Affiliation(s)
- Hyang-Mi Lee
- Laboratory of Biophysics, School of Biological Sciences, Institute of Microbiology, Seoul National University, Korea
| | - Ji-Sun Kim
- Laboratory of Biophysics, School of Biological Sciences, Institute of Microbiology, Seoul National University, Korea
| | - Sa-Ouk Kang
- Laboratory of Biophysics, School of Biological Sciences, Institute of Microbiology, Seoul National University, Korea
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11
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Fukujin F, Nakajima A, Shimada N, Sawai S. Self-organization of chemoattractant waves in Dictyostelium depends on F-actin and cell-substrate adhesion. J R Soc Interface 2016; 13:20160233. [PMID: 27358278 PMCID: PMC4938087 DOI: 10.1098/rsif.2016.0233] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 06/01/2016] [Indexed: 12/25/2022] Open
Abstract
In the social amoeba Dictyostelium discoideum, travelling waves of extracellular cyclic adenosine monophosphate (cAMP) self-organize in cell populations and direct aggregation of individual cells to form multicellular fruiting bodies. In contrast to the large body of studies that addressed how movement of cells is determined by spatial and temporal cues encoded in the dynamic cAMP gradients, how cell mechanics affect the formation of a self-generated chemoattractant field has received less attention. Here, we show, by live cell imaging analysis, that the periodicity of the synchronized cAMP waves increases in cells treated with the actin inhibitor latrunculin. Detail analysis of the extracellular cAMP-induced transients of cytosolic cAMP (cAMP relay response) in well-isolated cells demonstrated that their amplitude and duration were markedly reduced in latrunculin-treated cells. Similarly, in cells strongly adhered to a poly-l-lysine-coated surface, the response was suppressed, and the periodicity of the population-level oscillations was markedly lengthened. Our results suggest that cortical F-actin is dispensable for the basic low amplitude relay response but essential for its full amplification and that this enhanced response is necessary to establish high-frequency signalling centres. The observed F-actin dependence may prevent aggregation centres from establishing in microenvironments that are incompatible with cell migration.
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Affiliation(s)
- Fumihito Fukujin
- Department of Basic Science, Graduate School of Arts and Sciences, University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan
| | - Akihiko Nakajima
- Research Center for Complex Systems Biology, Graduate School of Arts and Sciences, University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan
| | - Nao Shimada
- Department of Basic Science, Graduate School of Arts and Sciences, University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan
| | - Satoshi Sawai
- Department of Basic Science, Graduate School of Arts and Sciences, University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan Research Center for Complex Systems Biology, Graduate School of Arts and Sciences, University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan PRESTO, Japan Science and Technology Agency, Kawaguchi-shi, Saitama 332-0012, Japan
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12
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Rodriguez-Centeno J, Sastre L. Biological Activity of the Alternative Promoters of the Dictyostelium discoideum Adenylyl Cyclase A Gene. PLoS One 2016; 11:e0148533. [PMID: 26840347 PMCID: PMC4739590 DOI: 10.1371/journal.pone.0148533] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 01/20/2016] [Indexed: 12/01/2022] Open
Abstract
Amoebae of the Dictyostelium discoideum species form multicellular fruiting bodies upon starvation. Cyclic adenosine monophosphate (cAMP) is used as intercellular signalling molecule in cell-aggregation, cell differentiation and morphogenesis. This molecule is synthesized by three adenylyl cyclases, one of which, ACA, is required for cell aggregation. The gene coding for ACA (acaA) is transcribed from three different promoters that are active at different developmental stages. Promoter 1 is active during cell-aggregation, promoters 2 and 3 are active in prespore and prestalk tip cells at subsequent developmental stages. The biological relevance of acaA expression from each of the promoters has been studied in this article. The acaA gene was expressed in acaA-mutant cells, that do not aggregate, under control of each of the three acaA promoters. acaA expression under promoter 1 control induced cell aggregation although subsequent development was delayed, very small fruiting bodies were formed and cell differentiation genes were expressed at very low levels. Promoter 2-driven acaA expression induced the formation of small aggregates and small fruiting bodies were formed at the same time as in wild-type strains and differentiation genes were also expressed at lower levels. Expression of acaA from promoter 3 induced aggregates and fruiting bodies formation and their size and the expression of differentiation genes were more similar to that of wild-type cells. Expression of acaA from promoters 1 and 2 in AX4 cells also produced smaller structures. In conclusion, the expression of acaA under control of the aggregation-specific Promoter 1 is able to induce cell aggregation in acaA-mutant strains. Expression from promoters 2 and 3 also recovered aggregation and development although promoter 3 induced a more complete recovery of fruiting body formation.
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Affiliation(s)
| | - Leandro Sastre
- Instituto de Investigaciones Biomédicas CSIC/UAM, C/Arturo Duperier, 4, 28029, Madrid, Spain
- CIBERER, Valencia, Spain
- * E-mail:
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Adenylyl cyclase localization to the uropod of aggregating Dictyostelium cells requires RacC. Biochem Biophys Res Commun 2015; 465:613-9. [PMID: 26315268 DOI: 10.1016/j.bbrc.2015.08.072] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 08/17/2015] [Indexed: 11/21/2022]
Abstract
The localization of adenylyl cyclase A (ACA) to uropod of cells is required for the stream formation during Dictyostelium development. RacC is a Dictyostelium orthologue of Cdc42. We identified a streaming defect of racC(-) cells as they are clearly less polarized and form smaller and fragmented streams. ACA-YFP is mainly associated with intracellular vesicular structures, but not with the plasma membrane in racC(-) cells. racC(-) cells have a slightly higher number of vesicles than Ax3 cells, suggesting that the defect of ACA trafficking is not simply due to the lack of vesicle formation. While the ACA-YFP vesicles traveled with an average velocity of 9.1 μm/min in Ax3 cells, a slow and diffusional movement without direction with an average velocity of 4 μm/min was maintained in racC(-) cells. Images acquired by using total internal reflection fluorescence (TIRF) microscopy and fluorescence recovery after photobleaching (FRAP) analysis revealed that a significantly decreased number of ACA-YFP vesicles appeared near the cell membrane, indicating a defect in ACA-YFP vesicle trafficking. These results suggest an important role of RacC in the rapid and directional movements of ACA vesicles on microtubules to the plasma membrane, especially to the back of polarized cell.
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14
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Du Q, Kawabe Y, Schilde C, Chen ZH, Schaap P. The Evolution of Aggregative Multicellularity and Cell-Cell Communication in the Dictyostelia. J Mol Biol 2015; 427:3722-33. [PMID: 26284972 PMCID: PMC5055082 DOI: 10.1016/j.jmb.2015.08.008] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Revised: 06/30/2015] [Accepted: 08/03/2015] [Indexed: 10/30/2022]
Abstract
Aggregative multicellularity, resulting in formation of a spore-bearing fruiting body, evolved at least six times independently amongst both eukaryotes and prokaryotes. Amongst eukaryotes, this form of multicellularity is mainly studied in the social amoeba Dictyostelium discoideum. In this review, we summarise trends in the evolution of cell-type specialisation and behavioural complexity in the four major groups of Dictyostelia. We describe the cell-cell communication systems that control the developmental programme of D. discoideum, highlighting the central role of cAMP in the regulation of cell movement and cell differentiation. Comparative genomic studies showed that the proteins involved in cAMP signalling are deeply conserved across Dictyostelia and their unicellular amoebozoan ancestors. Comparative functional analysis revealed that cAMP signalling in D. discoideum originated from a second messenger role in amoebozoan encystation. We highlight some molecular changes in cAMP signalling genes that were responsible for the novel roles of cAMP in multicellular development.
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Affiliation(s)
- Qingyou Du
- College of Life Sciences, University of Dundee, Dundee DD1 4HN, United Kingdom.
| | - Yoshinori Kawabe
- College of Life Sciences, University of Dundee, Dundee DD1 4HN, United Kingdom.
| | - Christina Schilde
- College of Life Sciences, University of Dundee, Dundee DD1 4HN, United Kingdom.
| | - Zhi-Hui Chen
- College of Life Sciences, University of Dundee, Dundee DD1 4HN, United Kingdom.
| | - Pauline Schaap
- College of Life Sciences, University of Dundee, Dundee DD1 4HN, United Kingdom.
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15
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Mohamed W, Ray S, Brazill D, Baskar R. Absence of catalytic domain in a putative protein kinase C (PkcA) suppresses tip dominance in Dictyostelium discoideum. Dev Biol 2015; 405:10-20. [PMID: 26183108 DOI: 10.1016/j.ydbio.2015.05.021] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Revised: 04/06/2015] [Accepted: 05/28/2015] [Indexed: 12/22/2022]
Abstract
A number of organisms possess several isoforms of protein kinase C but little is known about the significance of any specific isoform during embryogenesis and development. To address this we characterized a PKC ortholog (PkcA; DDB_G0288147) in Dictyostelium discoideum. pkcA expression switches from prestalk in mound to prespore in slug, indicating a dynamic expression pattern. Mutants lacking the catalytic domain of PkcA (pkcA(-)) did not exhibit tip dominance. A striking phenotype of pkcA- was the formation of an aggregate with a central hollow, and aggregates later fragmented to form small mounds, each becoming a fruiting body. Optical density wave patterns of cAMP in the late aggregates showed several cAMP wave generation centers. We attribute these defects in pkcA(-) to impaired cAMP signaling, altered cell motility and decreased expression of the cell adhesion molecules - CadA and CsaA. pkcA(-) slugs showed ectopic expression of ecmA in the prespore region. Further, the use of a PKC-specific inhibitor, GF109203X that inhibits the activity of catalytic domain phenocopied pkcA(-).
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Affiliation(s)
- Wasima Mohamed
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai 600036, India
| | - Sibnath Ray
- Department of Biological Sciences, Center for Translational and Basic Research, Hunter College and The Graduate Center of the City University of New York, New York, NY 10065, USA
| | - Derrick Brazill
- Department of Biological Sciences, Center for Translational and Basic Research, Hunter College and The Graduate Center of the City University of New York, New York, NY 10065, USA
| | - Ramamurthy Baskar
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai 600036, India.
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16
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Pineda M, Weijer CJ, Eftimie R. Modelling cell movement, cell differentiation, cell sorting and proportion regulation in Dictyostelium discoideum aggregations. J Theor Biol 2015; 370:135-50. [PMID: 25665718 DOI: 10.1016/j.jtbi.2015.01.042] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2014] [Revised: 11/27/2014] [Accepted: 01/27/2015] [Indexed: 11/25/2022]
Abstract
Understanding the mechanisms that control tissue morphogenesis and homeostasis is a central goal not only in developmental biology but also has great relevance for our understanding of various diseases, including cancer. A model organism that is widely used to study the control of tissue morphogenesis and proportioning is the Dictyostelium discoideum. While there are mathematical models describing the role of chemotactic cell motility in the Dictyostelium assembly and morphogenesis of multicellular tissues, as well as models addressing possible mechanisms of proportion regulation, there are no models incorporating both these key aspects of development. In this paper, we introduce a 1D hyperbolic model to investigate the role of two morphogens, DIF and cAMP, on cell movement, cell sorting, cell-type differentiation and proportioning in Dictyostelium discoideum. First, we use the non-spatial version of the model to study cell-type transdifferentiation. We perform a steady-state analysis of it and show that, depending on the shape of the differentiation rate functions, multiple steady-state solutions may occur. Then we incorporate spatial dynamics into the model, and investigate the transdifferentiation and spatial positioning of cells inside the newly formed structures, following the removal of prestalk or prespore regions of a Dictyostelium slug. We show that in isolated prespore fragments, a tipped mound-like aggregate can be formed after a transdifferentiation from prespore to prestalk cells and following the sorting of prestalk cells to the centre of the aggregate. For isolated prestalk fragments, we show the formation of a slug-like structure containing the usual anterior-posterior pattern of prestalk and prespore cells.
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Affiliation(s)
- M Pineda
- Division of Mathematics, University of Dundee, Dundee DD1 4HN, United Kingdom.
| | - C J Weijer
- School of Life Sciences, University of Dundee, Dundee DD1 4HN, United Kingdom.
| | - R Eftimie
- Division of Mathematics, University of Dundee, Dundee DD1 4HN, United Kingdom.
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17
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Sgro AE, Schwab DJ, Noorbakhsh J, Mestler T, Mehta P, Gregor T. From intracellular signaling to population oscillations: bridging size- and time-scales in collective behavior. Mol Syst Biol 2015; 11:779. [PMID: 25617347 PMCID: PMC4332153 DOI: 10.15252/msb.20145352] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Collective behavior in cellular populations is coordinated by biochemical signaling networks within individual cells. Connecting the dynamics of these intracellular networks to the population phenomena they control poses a considerable challenge because of network complexity and our limited knowledge of kinetic parameters. However, from physical systems, we know that behavioral changes in the individual constituents of a collectively behaving system occur in a limited number of well-defined classes, and these can be described using simple models. Here, we apply such an approach to the emergence of collective oscillations in cellular populations of the social amoeba Dictyostelium discoideum. Through direct tests of our model with quantitative in vivo measurements of single-cell and population signaling dynamics, we show how a simple model can effectively describe a complex molecular signaling network at multiple size and temporal scales. The model predicts novel noise-driven single-cell and population-level signaling phenomena that we then experimentally observe. Our results suggest that like physical systems, collective behavior in biology may be universal and described using simple mathematical models.
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Affiliation(s)
- Allyson E Sgro
- Joseph Henry Laboratories of Physics, Princeton University, Princeton, NJ, USA Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
| | - David J Schwab
- Joseph Henry Laboratories of Physics, Princeton University, Princeton, NJ, USA Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
| | | | - Troy Mestler
- Joseph Henry Laboratories of Physics, Princeton University, Princeton, NJ, USA
| | - Pankaj Mehta
- Department of Physics, Boston University, Boston, MA, USA
| | - Thomas Gregor
- Joseph Henry Laboratories of Physics, Princeton University, Princeton, NJ, USA Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
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18
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Gholami A, Steinbock O, Zykov V, Bodenschatz E. Flow-driven waves and phase-locked self-organization in quasi-one-dimensional colonies of Dictyostelium discoideum. PHYSICAL REVIEW LETTERS 2015; 114:018103. [PMID: 25615506 DOI: 10.1103/physrevlett.114.018103] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Indexed: 06/04/2023]
Abstract
We report experiments on flow-driven waves in a microfluidic channel containing the signaling slime mold Dictyostelium discoideum. The observed cyclic adenosine monophosphate (cAMP) wave trains developed spontaneously in the presence of flow and propagated with the velocity proportional to the imposed flow velocity. The period of the wave trains was independent of the flow velocity. Perturbations of flow-driven waves via external periodic pulses of the signaling agent cAMP induced 1∶1, 2∶1, 3∶1, and 1∶2 frequency responses, reminiscent of Arnold tongues in forced oscillatory systems. We expect our observations to be generic to active media governed by reaction-diffusion-advection dynamics, where spatially bound autocatalytic processes occur under flow conditions.
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Affiliation(s)
- A Gholami
- Max Planck Institute for Dynamics and Self-Organization, Am Fassberg 17, D-37077 Göttingen, Germany
| | - O Steinbock
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306-4390, USA
| | - V Zykov
- Max Planck Institute for Dynamics and Self-Organization, Am Fassberg 17, D-37077 Göttingen, Germany
| | - E Bodenschatz
- Max Planck Institute for Dynamics and Self-Organization, Am Fassberg 17, D-37077 Göttingen, Germany and Institute for Nonlinear Dynamics, University of Göttingen, D-37073 Göttingen, Germany and Laboratory of Atomic and Solid-State Physics and Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, New York 14853, USA
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19
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Seifert R, Schneider EH, Bähre H. From canonical to non-canonical cyclic nucleotides as second messengers: pharmacological implications. Pharmacol Ther 2014; 148:154-84. [PMID: 25527911 DOI: 10.1016/j.pharmthera.2014.12.002] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 12/11/2014] [Indexed: 02/07/2023]
Abstract
This review summarizes our knowledge on the non-canonical cyclic nucleotides cCMP, cUMP, cIMP, cXMP and cTMP. We place the field into a historic context and discuss unresolved questions and future directions of research. We discuss the implications of non-canonical cyclic nucleotides for experimental and clinical pharmacology, focusing on bacterial infections, cardiovascular and neuropsychiatric disorders and reproduction medicine. The canonical cyclic purine nucleotides cAMP and cGMP fulfill the criteria of second messengers. (i) cAMP and cGMP are synthesized by specific generators, i.e. adenylyl and guanylyl cyclases, respectively. (ii) cAMP and cGMP activate specific effector proteins, e.g. protein kinases. (iii) cAMP and cGMP exert specific biological effects. (iv) The biological effects of cAMP and cGMP are terminated by phosphodiesterases and export. The effects of cAMP and cGMP are mimicked by (v) membrane-permeable cyclic nucleotide analogs and (vi) bacterial toxins. For decades, the existence and relevance of cCMP and cUMP have been controversial. Modern mass-spectrometric methods have unequivocally demonstrated the existence of cCMP and cUMP in mammalian cells. For both, cCMP and cUMP, the criteria for second messenger molecules are now fulfilled as well. There are specific patterns by which nucleotidyl cyclases generate cNMPs and how they are degraded and exported, resulting in unique cNMP signatures in biological systems. cNMP signaling systems, specifically at the level of soluble guanylyl cyclase, soluble adenylyl cyclase and ExoY from Pseudomonas aeruginosa are more promiscuous than previously appreciated. cUMP and cCMP are evolutionary new molecules, probably reflecting an adaption to signaling requirements in higher organisms.
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Affiliation(s)
- Roland Seifert
- Institute of Pharmacology, Hannover Medical School, D-30625 Hannover, Germany.
| | - Erich H Schneider
- Institute of Pharmacology, Hannover Medical School, D-30625 Hannover, Germany
| | - Heike Bähre
- Institute of Pharmacology, Hannover Medical School, D-30625 Hannover, Germany
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20
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Chen ZH, Raffelberg S, Losi A, Schaap P, Gärtner W. A cyanobacterial light activated adenylyl cyclase partially restores development of a Dictyostelium discoideum, adenylyl cyclase a null mutant. J Biotechnol 2014; 191:246-9. [PMID: 25128613 PMCID: PMC4409636 DOI: 10.1016/j.jbiotec.2014.08.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 07/30/2014] [Accepted: 08/06/2014] [Indexed: 10/24/2022]
Abstract
A light-regulated adenylyl cyclase, mPAC, was previously identified from the cyanobacterium Microcoleus chthonoplastes PCC7420. MPAC consists of a flavin-based blue light-sensing LOV domain and a catalytic domain. In this work, we expressed mPAC in an adenylate cyclase A null mutant (aca-) of the eukaryote Dictyostelium discoideum and tested to what extent light activation of mPAC could restore the cAMP-dependent developmental programme of this organism. Amoebas of Dictyostelium, a well-established model organism, generate and respond to cAMP pulses, which cause them to aggregate and construct fruiting bodies. mPAC was expressed under control of a constitutive actin-15 promoter in D. discoideum and displayed low basal adenylyl cyclase activity in darkness that was about five-fold stimulated by blue light. mPAC expression in aca- cells marginally restored aggregation and fruiting body formation in darkness. However, more and larger fruiting bodies were formed when mPAC expressing cells were incubated in light. Extending former applications of light-regulated AC, these results demonstrate that mPAC can be used to manipulate multicellular development in eukaryotes in a light dependent manner.
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Affiliation(s)
- Zhi-Hui Chen
- College of Life Sciences, University of Dundee, Dundee, UK
| | | | - Aba Losi
- Department of Physics and Earth Sciences, University of Parma, Parma, Italy
| | - Pauline Schaap
- College of Life Sciences, University of Dundee, Dundee, UK.
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21
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Miranda ER, Nam EA, Kuspa A, Shaulsky G. The ABC transporter, AbcB3, mediates cAMP export in D. discoideum development. Dev Biol 2014; 397:203-11. [PMID: 25448698 DOI: 10.1016/j.ydbio.2014.11.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Revised: 10/15/2014] [Accepted: 11/11/2014] [Indexed: 11/24/2022]
Abstract
Extracellular cAMP functions as a primary ligand for cell surface cAMP receptors throughout Dictyostelium discoideum development, controlling chemotaxis and morphogenesis. The developmental consequences of cAMP signaling and the metabolism of cAMP have been studied in great detail, but it has been unclear how cells export cAMP across the plasma membrane. Here we show pharmacologically and genetically that ABC transporters mediate cAMP export. Using an evolutionary-developmental biology approach, we identified several candidate abc genes and characterized one of them, abcB3, in more detail. Genetic and biochemical evidence suggest that AbcB3 is a component of the cAMP export mechanism in D. discoideum development.
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Affiliation(s)
- Edward Roshan Miranda
- Graduate Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Edward A Nam
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Adam Kuspa
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Gad Shaulsky
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA.
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22
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Singh SP, Dhakshinamoorthy R, Jaiswal P, Schmidt S, Thewes S, Baskar R. The thyroxine inactivating gene, type III deiodinase, suppresses multiple signaling centers in Dictyostelium discoideum. Dev Biol 2014; 396:256-68. [PMID: 25446527 DOI: 10.1016/j.ydbio.2014.10.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Revised: 10/13/2014] [Accepted: 10/15/2014] [Indexed: 12/26/2022]
Abstract
Thyroxine deiodinases, the enzymes that regulate thyroxine metabolism, are essential for vertebrate growth and development. In the genome of Dictyostelium discoideum, a single intronless gene (dio3) encoding type III thyroxine 5' deiodinase is present. The amino acid sequence of D. discoideum Dio3 shares 37% identity with human T4 deiodinase and is a member of the thioredoxin reductase superfamily. dio3 is expressed throughout growth and development and by generating a knockout of dio3, we have examined the role of thyroxine 5' deiodinase in D. discoideum. dio3(-) had multiple defects that affected growth, timing of development, aggregate size, cell streaming, and cell-type differentiation. A prominent phenotype of dio3(-) was the breaking of late aggregates into small signaling centers, each forming a fruiting body of its own. cAMP levels, its relay, photo- and chemo-taxis were also defective in dio3(-). Quantitative RT-PCR analyses suggested that expression levels of genes encoding adenylyl cyclase A (acaA), cAMP-receptor A (carA) and cAMP-phosphodiesterases were reduced. There was a significant reduction in the expression of CadA and CsaA, which are involved in cell-cell adhesion. The dio3(-) slugs had prestalk identity, with pronounced prestalk marker ecmA expression. Thus, Dio3 seems to have roles in mediating cAMP synthesis/relay, cell-cell adhesion and slug patterning. The phenotype of dio3(-) suggests that Dio3 may prevent the formation of multiple signaling centers during D. discoideum development. This is the first report of a gene involved in thyroxine metabolism that is also involved in growth and development in a lower eukaryote.
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Affiliation(s)
- Shashi Prakash Singh
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology-Madras, Chennai 600036, India
| | - Ranjani Dhakshinamoorthy
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology-Madras, Chennai 600036, India
| | - Pundrik Jaiswal
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology-Madras, Chennai 600036, India
| | - Stefanie Schmidt
- Institute for Biology - Microbiology, Department of Biology, Chemistry, Pharmacy, Freie Universität Berlin, 14195 Berlin, Germany
| | - Sascha Thewes
- Institute for Biology - Microbiology, Department of Biology, Chemistry, Pharmacy, Freie Universität Berlin, 14195 Berlin, Germany
| | - Ramamurthy Baskar
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology-Madras, Chennai 600036, India.
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23
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Cai D, Montell DJ. Diverse and dynamic sources and sinks in gradient formation and directed migration. Curr Opin Cell Biol 2014; 30:91-8. [PMID: 25022255 DOI: 10.1016/j.ceb.2014.06.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Revised: 06/17/2014] [Accepted: 06/17/2014] [Indexed: 02/08/2023]
Abstract
The traditional view of directional cell migration within a tissue is that it requires a gradient of a soluble attractive chemical that is stable in space and time due to the presence of a source and a sink. However, advances in live imaging technology and the ability to study cell migration in vivo have revealed that endogenous sources and sinks are typically far more varied and complex. Both sources and sinks can be made up of multiple tissues. During long-range migrations, cells tend to divide up their trajectories and follow different source signals in each segment. When a single source signal is used repeatedly in each segment, its expression is dynamically controlled. Source signals can also originate locally from neighboring migrating cells. Sinks are important in some cases but not all, to sculpt a permissive migratory path or allow cells to move from one intermediate target to another. Migrating cells themselves can function as sinks to create a gradient out of an initially uniform chemoattractant. These diverse ways of building sources and sinks allow different cell types to navigate distinct trajectories through the same embryo even as the whole embryo undergoes the dramatic changes in cell number, position, arrangement and fate that are the essence of development.
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Affiliation(s)
- Danfeng Cai
- Department of Biological Chemistry, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA; Molecular, Cellular and Developmental Biology Department, University of California, Santa Barbara, CA 93106-9625, USA
| | - Denise J Montell
- Molecular, Cellular and Developmental Biology Department, University of California, Santa Barbara, CA 93106-9625, USA.
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24
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Blackstone NW. sAC as a model for understanding the impact of endosymbiosis on cell signaling. Biochim Biophys Acta Mol Basis Dis 2014; 1842:2548-54. [PMID: 24907565 DOI: 10.1016/j.bbadis.2014.05.037] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Revised: 05/23/2014] [Accepted: 05/28/2014] [Indexed: 11/25/2022]
Abstract
As signaling pathways evolve, selection for new functions guides the co-option of existing material. Major transitions in the history of life, including the evolution of eukaryotes and multicellularity, exemplify this process. These transitions provided both strong selection and a plenitude of available material for the evolution of signaling pathways. Mechanisms that evolved to mediate conflict during the evolution of eukaryotes may subsequently have been co-opted during the many independent derivations of multicellularity. The soluble adenylyl cyclase (sAC) signaling pathway illustrates this hypothesis. Class III adenylyl cyclases, which include sAC, are found in bacteria, including the α-proteobacteria. These adenylyl cyclases are the only ones present in eukaryotes but appear to be absent in archaeans. This pattern suggests that the mitochondrial endosymbiosis brought sAC signaling to eukaryotes as part of an intact module. After transfer to the proto-nuclear genome, this module was then co-opted into numerous new functions. In the evolution of eukaryotes, sAC signaling may have mediated conflicts by maintaining metabolic homeostasis. In the evolution of multicellularity, in different lineages sAC may have been co-opted into parallel tasks originally related to conflict mediation. Elucidating the history of the sAC pathway may be relatively straightforward because it is ubiquitous and linked to near universal metabolic by-products (CO₂/HCO(3)(-)). Other signaling pathways (e.g., those involving STAT and VEGF) present a greater challenge but may suggest a complementary pattern. The impact of the mitochondrial endosymbiosis on cell signaling may thus have been profound. This article is part of a Special Issue entitled: The role of soluble adenylyl cyclase in health and disease.
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Affiliation(s)
- Neil W Blackstone
- Department of Biological Sciences, Northern Illinois University, DeKalb, IL 60115, USA.
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25
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Garciandia A, Suarez T. The NMRA/NMRAL1 homologue PadA modulates the expression of extracellular cAMP relay genes during aggregation in Dictyostelium discoideum. Dev Biol 2013; 381:411-22. [PMID: 23773804 DOI: 10.1016/j.ydbio.2013.06.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 06/04/2013] [Accepted: 06/07/2013] [Indexed: 02/08/2023]
Abstract
NMRA-like proteins belong to a class of conserved transcriptional regulators that function as direct sensors of the metabolic state of the cell and link basic metabolism to changes in gene expression. PadA was the first NMRA-like protein described in Dictyostelium discoideum and was shown to be necessary for prestalk cell differentiation and correct development. We describe and characterize padA(-) mutant phenotype during the onset of development, which results in the formation of abnormally small territories and impairment of cAMP responses. Transcriptional analysis shows that cAMP-induced gene expression is downregulated in padA(-), particularly the genes that establish the extracellular cAMP relay. The mutant phenotype can be rescued with the constitutive expression of one of these genes, carA, encoding the cAMP receptor. Transcriptional analysis of padA(-)/A15::carA showed that carA maximum mRNA levels were not reached during aggregation. Our data support a regulatory role for PadA on the regulation of extracellular cAMP relay genes during aggregation and suggest that PadA is required to achieve carA full induction.
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Affiliation(s)
- Ane Garciandia
- Department of Cellular and Molecular Medicine, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu, 9, 28040 Madrid, Spain
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26
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Sultana H, Neelakanta G, Rivero F, Blau-Wasser R, Schleicher M, Noegel AA. Ectopic expression of cyclase associated protein CAP restores the streaming and aggregation defects of adenylyl cyclase a deficient Dictyostelium discoideum cells. BMC DEVELOPMENTAL BIOLOGY 2012; 12:3. [PMID: 22239817 PMCID: PMC3316131 DOI: 10.1186/1471-213x-12-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/17/2011] [Accepted: 01/12/2012] [Indexed: 12/02/2022]
Abstract
Background Cell adhesion, an integral part of D. discoideum development, is important for morphogenesis and regulated gene expression in the multicellular context and is required to trigger cell-differentiation. G-protein linked adenylyl cyclase pathways are crucially involved and a mutant lacking the aggregation specific adenylyl cyclase ACA does not undergo multicellular development. Results Here, we have investigated the role of cyclase-associated protein (CAP), an important regulator of cell polarity and F-actin/G-actin ratio in the aca- mutant. We show that ectopic expression of GFP-CAP improves cell polarization, streaming and aggregation in aca- cells, but it fails to completely restore development. Our studies indicate a requirement of CAP in the ACA dependent signal transduction for progression of the development of unicellular amoebae into multicellular structures. The reduced expression of the cell adhesion molecule DdCAD1 together with csA is responsible for the defects in aca- cells to initiate multicellular development. Early development was restored by the expression of GFP-CAP that enhanced the DdCAD1 transcript levels and to a lesser extent the csA mRNA levels. Conclusions Collectively, our data shows a novel role of CAP in regulating cell adhesion mechanisms during development that might be envisioned to unravel the functions of mammalian CAP during animal embryogenesis.
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Affiliation(s)
- Hameeda Sultana
- Center for Biochemistry, Medical Faculty, University of Cologne, 50931 Köln, Germany.
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Heidel AJ, Lawal HM, Felder M, Schilde C, Helps NR, Tunggal B, Rivero F, John U, Schleicher M, Eichinger L, Platzer M, Noegel AA, Schaap P, Glöckner G. Phylogeny-wide analysis of social amoeba genomes highlights ancient origins for complex intercellular communication. Genome Res 2011; 21:1882-91. [PMID: 21757610 PMCID: PMC3205573 DOI: 10.1101/gr.121137.111] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2011] [Accepted: 07/11/2011] [Indexed: 11/24/2022]
Abstract
Dictyostelium discoideum (DD), an extensively studied model organism for cell and developmental biology, belongs to the most derived group 4 of social amoebas, a clade of altruistic multicellular organisms. To understand genome evolution over long time periods and the genetic basis of social evolution, we sequenced the genomes of Dictyostelium fasciculatum (DF) and Polysphondylium pallidum (PP), which represent the early diverging groups 1 and 2, respectively. In contrast to DD, PP and DF have conventional telomere organization and strongly reduced numbers of transposable elements. The number of protein-coding genes is similar between species, but only half of them comprise an identifiable set of orthologous genes. In general, genes involved in primary metabolism, cytoskeletal functions and signal transduction are conserved, while genes involved in secondary metabolism, export, and signal perception underwent large differential gene family expansions. This most likely signifies involvement of the conserved set in core cell and developmental mechanisms, and of the diverged set in niche- and species-specific adaptations for defense and food, mate, and kin selection. Phylogenetic dating using a concatenated data set and extensive loss of synteny indicate that DF, PP, and DD split from their last common ancestor at least 0.6 billion years ago.
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Affiliation(s)
- Andrew J. Heidel
- Leibniz Institute for Age Research–Fritz Lipmann Institute, D-07745 Jena, Germany
| | - Hajara M. Lawal
- College of Life Sciences, University of Dundee, Dundee DD1 5EH, United Kingdom
| | - Marius Felder
- Leibniz Institute for Age Research–Fritz Lipmann Institute, D-07745 Jena, Germany
| | - Christina Schilde
- College of Life Sciences, University of Dundee, Dundee DD1 5EH, United Kingdom
| | - Nicholas R. Helps
- College of Life Sciences, University of Dundee, Dundee DD1 5EH, United Kingdom
| | - Budi Tunggal
- Institute of Biochemistry I, Medical Faculty, Center for Molecular Medicine Cologne (CMMC) and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, D-50931 Cologne, Germany
| | - Francisco Rivero
- Hull York Medical School and Department of Biological Sciences, University of Hull, Hull HU6 7RX, United Kingdom
| | - Uwe John
- Alfred Wegener Institute, D-27570 Bremerhaven, Germany
| | - Michael Schleicher
- Institute for Anatomy and Cell Biology, and Center for Integrated Protein Science (CIPSM), Ludwig-Maximilians-University Munich, D-80336 Munich, Germany
| | - Ludwig Eichinger
- Institute of Biochemistry I, Medical Faculty, Center for Molecular Medicine Cologne (CMMC) and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, D-50931 Cologne, Germany
| | - Matthias Platzer
- Leibniz Institute for Age Research–Fritz Lipmann Institute, D-07745 Jena, Germany
| | - Angelika A. Noegel
- Institute of Biochemistry I, Medical Faculty, Center for Molecular Medicine Cologne (CMMC) and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, D-50931 Cologne, Germany
| | - Pauline Schaap
- College of Life Sciences, University of Dundee, Dundee DD1 5EH, United Kingdom
| | - Gernot Glöckner
- Leibniz Institute for Age Research–Fritz Lipmann Institute, D-07745 Jena, Germany
- Institute of Biochemistry I, Medical Faculty, Center for Molecular Medicine Cologne (CMMC) and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, D-50931 Cologne, Germany
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries, D-12587 Berlin, Germany
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28
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Huang E, Talukder S, Hughes TR, Curk T, Zupan B, Shaulsky G, Katoh-Kurasawa M. BzpF is a CREB-like transcription factor that regulates spore maturation and stability in Dictyostelium. Dev Biol 2011; 358:137-46. [PMID: 21810415 PMCID: PMC3180911 DOI: 10.1016/j.ydbio.2011.07.017] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2011] [Revised: 07/08/2011] [Accepted: 07/13/2011] [Indexed: 12/31/2022]
Abstract
The cAMP response element-binding protein (CREB) is a highly conserved transcription factor that integrates signaling through the cAMP-dependent protein kinase A (PKA) in many eukaryotes. PKA plays a critical role in Dictyostelium development but no CREB homologue has been identified in this system. Here we show that Dictyostelium utilizes a CREB-like protein, BzpF, to integrate PKA signaling during late development. bzpF(-) mutants produce compromised spores, which are extremely unstable and germination defective. Previously, we have found that BzpF binds the canonical CRE motif in vitro. In this paper, we determined the DNA binding specificity of BzpF using protein binding microarray (PBM) and showed that the motif with the highest specificity is a CRE-like sequence. BzpF is necessary to activate the transcription of at least 15 PKA-regulated, late-developmental target genes whose promoters contain BzpF binding motifs. BzpF is sufficient to activate two of these genes. The comparison of RNA sequencing data between wild type and bzpF(-) mutant revealed that the mutant fails to express 205 genes, many of which encode cellulose-binding and sugar-binding proteins. We propose that BzpF is a CREB-like transcription factor that regulates spore maturation and stability in a PKA-related manner.
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Affiliation(s)
- Eryong Huang
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston TX 77030, USA
| | - Shaheynoor Talukder
- Banting and Best Department of Medical Research, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Timothy R. Hughes
- Banting and Best Department of Medical Research, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Tomaz Curk
- Faculty of Computer and Information Science, University of Ljubljana, Trzaska cesta 25, SI-1001 Ljubljana, Slovenia
| | - Blaz Zupan
- Faculty of Computer and Information Science, University of Ljubljana, Trzaska cesta 25, SI-1001 Ljubljana, Slovenia
| | - Gad Shaulsky
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston TX 77030, USA
| | - Mariko Katoh-Kurasawa
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston TX 77030, USA
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Kamino K, Fujimoto K, Sawai S. Collective oscillations in developing cells: insights from simple systems. Dev Growth Differ 2011; 53:503-17. [PMID: 21585355 DOI: 10.1111/j.1440-169x.2011.01266.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
From hormonal secretion to gene expression, multicellular dynamics are rich in oscillatory regulation. When organized in space and time, periodic cell-cell signaling can give rise to long-range coordination of gene expression and cell movement in tissues. Lack of synchrony of the oscillations on the other hand can serve as a source of initial divergence of cell fate in stem cells. How properties of individual cells can account for collective rhythmic behaviors at the tissue level remains elusive in most cases. Recently, studies in chemical reactions, synthetic gene circuits, yeast and social amoeba Dictyostelium have greatly enhanced our view of collective oscillations in cell populations. From these relatively simple systems, a unified view of how excitable and oscillatory regulations could be tuned and coupled to give rise to tissue-level oscillations is emerging. The review focuses on recent progress in cyclic adenosine monophosphate oscillations in Dictyostelium and highlights similarities and differences with other systems. We will see that the autonomy of single-cell level oscillations and different ways in which cells are coupled influence how group-level information can be encoded in collective oscillations.
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Affiliation(s)
- Keita Kamino
- Graduate School of Arts and Sciences, University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo, Japan
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30
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Atkinson GC, Tenson T, Hauryliuk V. The RelA/SpoT homolog (RSH) superfamily: distribution and functional evolution of ppGpp synthetases and hydrolases across the tree of life. PLoS One 2011; 6:e23479. [PMID: 21858139 PMCID: PMC3153485 DOI: 10.1371/journal.pone.0023479] [Citation(s) in RCA: 316] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Accepted: 07/18/2011] [Indexed: 12/01/2022] Open
Abstract
RelA/SpoT Homologue (RSH) proteins, named for their sequence similarity to the RelA and SpoT enzymes of Escherichia coli, comprise a superfamily of enzymes that synthesize and/or hydrolyze the alarmone ppGpp, activator of the “stringent” response and regulator of cellular metabolism. The classical “long” RSHs Rel, RelA and SpoT with the ppGpp hydrolase, synthetase, TGS and ACT domain architecture have been found across diverse bacteria and plant chloroplasts, while dedicated single domain ppGpp-synthesizing and -hydrolyzing RSHs have also been discovered in disparate bacteria and animals respectively. However, there is considerable confusion in terms of nomenclature and no comprehensive phylogenetic and sequence analyses have previously been carried out to classify RSHs on a genomic scale. We have performed high-throughput sensitive sequence searching of over 1000 genomes from across the tree of life, in combination with phylogenetic analyses to consolidate previous ad hoc identification of diverse RSHs in different organisms and provide a much-needed unifying terminology for the field. We classify RSHs into 30 subgroups comprising three groups: long RSHs, small alarmone synthetases (SASs), and small alarmone hydrolases (SAHs). Members of nineteen previously unidentified RSH subgroups can now be studied experimentally, including previously unknown RSHs in archaea, expanding the “stringent response” to this domain of life. We have analyzed possible combinations of RSH proteins and their domains in bacterial genomes and compared RSH content with available RSH knock-out data for various organisms to determine the rules of combining RSHs. Through comparative sequence analysis of long and small RSHs, we find exposed sites limited in conservation to the long RSHs that we propose are involved in transmitting regulatory signals. Such signals may be transmitted via NTD to CTD intra-molecular interactions, or inter-molecular interactions either among individual RSH molecules or among long RSHs and other binding partners such as the ribosome.
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Abstract
The social amoeba Dictyostelium discoideum is one of the leading model systems used to study how cells count themselves to determine the number and/or density of cells. In this review, we describe work on three different cell-density sensing systems used by Dictyostelium. The first involves a negative feedback loop in which two secreted signals inhibit cell proliferation during the growth phase. As the cell density increases, the concentrations of the secreted factors concomitantly increase, allowing the cells to sense their density. The two signals act as message authenticators for each other, and the existence of two different signals that require each other for activity may explain why previous efforts to identify autocrine proliferation-inhibiting signals in higher eukaryotes have generally failed. The second system involves a signal made by growing cells that is secreted only when they starve. This then allows cells to sense the density of just the starving cells, and is an example of a mechanism that allows cells in a tissue to sense the density of one specific cell type. The third cell density counting system involves cells in aggregation streams secreting a signal that limits the size of fruiting bodies. Computer simulations predicted, and experiments then showed, that the factor increases random cell motility and decreases cell-cell adhesion to cause streams to break up if there are too many cells in the stream. Together, studies on Dictyostelium cell density counting systems will help elucidate how higher eukaryotes regulate the size and composition of tissues.
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Affiliation(s)
- Richard H Gomer
- Department of Biology, ILSB MS 3474, Texas A&M University, College Station, Texas 77843-3474, USA.
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Asghar A, Groth M, Siol O, Gaube F, Enzensperger C, Glöckner G, Winckler T. Developmental gene regulation by an ancient intercellular communication system in social amoebae. Protist 2011; 163:25-37. [PMID: 21371934 DOI: 10.1016/j.protis.2010.12.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Accepted: 12/25/2010] [Indexed: 10/18/2022]
Abstract
The social amoebae (Dictyostelia) use quorum sensing-like communication systems to coordinate the periodic transition from uni- to multicellularity. The monophyletic descent of the Dictyostelia provides a unique opportunity to study the origin and adaptive evolution of such intercellular communication systems. We determined that the ability of aggregation-competent cells to respond to the intercellular messenger glorin occurred in the most ancient taxa of the Dictyostelia. We show using Illumina sequencing technology that glorin mediates rapid changes in gene expression at the transition from vegetative growth to aggregation. We conclude that peptide-based communication is the most ancient form of intercellular signaling in the evolution of multicellularity in the social amoebae, but has been repeatedly replaced by other communication systems during the monophyletic evolution of the social amoebae. Glorin communication has parallels with quorum sensing in that the molecule diffuses into the field, stimulates gene expression in receptive cells and coordinates a population-wide response.
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Affiliation(s)
- Asma Asghar
- School of Biology and Pharmacy, Institute of Pharmacy, Department of Pharmaceutical Biology, University of Jena, Semmelweisstrasse 10, 07743 Jena, Germany
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Sucgang R, Kuo A, Tian X, Salerno W, Parikh A, Feasley CL, Dalin E, Tu H, Huang E, Barry K, Lindquist E, Shapiro H, Bruce D, Schmutz J, Salamov A, Fey P, Gaudet P, Anjard C, Babu MM, Basu S, Bushmanova Y, van der Wel H, Katoh-Kurasawa M, Dinh C, Coutinho PM, Saito T, Elias M, Schaap P, Kay RR, Henrissat B, Eichinger L, Rivero F, Putnam NH, West CM, Loomis WF, Chisholm RL, Shaulsky G, Strassmann JE, Queller DC, Kuspa A, Grigoriev IV. Comparative genomics of the social amoebae Dictyostelium discoideum and Dictyostelium purpureum. Genome Biol 2011; 12:R20. [PMID: 21356102 PMCID: PMC3188802 DOI: 10.1186/gb-2011-12-2-r20] [Citation(s) in RCA: 125] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2010] [Revised: 12/09/2010] [Accepted: 02/28/2011] [Indexed: 12/28/2022] Open
Abstract
Background The social amoebae (Dictyostelia) are a diverse group of Amoebozoa that achieve multicellularity by aggregation and undergo morphogenesis into fruiting bodies with terminally differentiated spores and stalk cells. There are four groups of dictyostelids, with the most derived being a group that contains the model species Dictyostelium discoideum. Results We have produced a draft genome sequence of another group dictyostelid, Dictyostelium purpureum, and compare it to the D. discoideum genome. The assembly (8.41 × coverage) comprises 799 scaffolds totaling 33.0 Mb, comparable to the D. discoideum genome size. Sequence comparisons suggest that these two dictyostelids shared a common ancestor approximately 400 million years ago. In spite of this divergence, most orthologs reside in small clusters of conserved synteny. Comparative analyses revealed a core set of orthologous genes that illuminate dictyostelid physiology, as well as differences in gene family content. Interesting patterns of gene conservation and divergence are also evident, suggesting function differences; some protein families, such as the histidine kinases, have undergone little functional change, whereas others, such as the polyketide synthases, have undergone extensive diversification. The abundant amino acid homopolymers encoded in both genomes are generally not found in homologous positions within proteins, so they are unlikely to derive from ancestral DNA triplet repeats. Genes involved in the social stage evolved more rapidly than others, consistent with either relaxed selection or accelerated evolution due to social conflict. Conclusions The findings from this new genome sequence and comparative analysis shed light on the biology and evolution of the Dictyostelia.
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Affiliation(s)
- Richard Sucgang
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
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Chen ZH, Schilde C, Schaap P. Functional dissection of adenylate cyclase R, an inducer of spore encapsulation. J Biol Chem 2010; 285:41724-31. [PMID: 20966074 PMCID: PMC3009899 DOI: 10.1074/jbc.m110.156380] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cyclic AMP acting on protein kinase A controls sporulation and encystation in social and solitary amoebas. In Dictyostelium discoideum, adenylate cyclase R (ACR), is essential for spore encapsulation. In addition to its cyclase (AC) domain, ACR harbors seven transmembrane helices, a histidine kinase domain, and two receiver domains. We investigated the role of these domains in the regulation of AC activity. Expression of an ACR-YFP fusion protein in acr(-) cells rescued their sporulation defective phenotype and revealed that ACR is associated with the nuclear envelope and endoplasmic reticulum. Loss of the transmembrane helices (ΔTM) caused a 60% reduction of AC activity, but ΔTM-ACR still rescued the acr(-) phenotype. The isolated AC domain was properly expressed but inactive. Mutation of three essential ATP-binding residues in the histidine kinase domain did not affect the AC activity or phenotypic rescue. Mutation of the essential phosphoryl-accepting aspartate in receivers 1, 2, or both had only modest effects on AC activity and did not affect phenotypic rescue, indicating that AC activity is not critically regulated by phosphorelay. Remarkably, the dimerizing histidine phosphoacceptor subdomain, which in ACR lacks the canonical histidine for autophosphorylation, was essential for AC activity. Transformation of wild-type cells with an ACR allele (ΔCRA) that is truncated after this domain inhibited AC activity of endogenous ACR and replicated the acr(-) phenotype. Combined with the observation that the isolated AC domain was inactive, the dominant-negative effect of ΔCRA strongly suggests that the defunct phosphoacceptor domain acquired a novel role in enforcing dimerization of the AC domain.
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Affiliation(s)
- Zhi-hui Chen
- College of Life Sciences, University of Dundee, Dundee DD15EH, Scotland, United Kingdom
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35
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Galardi-Castilla M, Garciandía A, Suarez T, Sastre L. The Dictyostelium discoideum acaA gene is transcribed from alternative promoters during aggregation and multicellular development. PLoS One 2010; 5:e13286. [PMID: 20949015 PMCID: PMC2952602 DOI: 10.1371/journal.pone.0013286] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2010] [Accepted: 09/15/2010] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Extracellular cAMP is a key extracellular signaling molecule that regulates aggregation, cell differentiation and morphogenesis during multi-cellular development of the social amoeba Dictyostelium discoideum. This molecule is produced by three different adenylyl cyclases, encoded by the genes acaA, acrA and acgA, expressed at different stages of development and in different structures. METHODOLOGY/PRINCIPAL FINDINGS This article describes the characterization of the promoter region of the acaA gene, showing that it is transcribed from three different alternative promoters. The distal promoter, promoter 1, is active during the aggregation process while the more proximal promoters are active in tip-organiser and posterior regions of the structures. A DNA fragment containing the three promoters drove expression to these same regions and similar results were obtained by in situ hybridization. Analyses of mRNA expression by quantitative RT-PCR with specific primers for each of the three transcripts also demonstrated their different temporal patterns of expression. CONCLUSIONS/SIGNIFICANCE The existence of an aggregation-specific promoter can be associated with the use of cAMP as chemo-attractant molecule, which is specific for some Dictyostelium species. Expression at late developmental stages indicates that adenylyl cyclase A might play a more important role in post-aggregative development than previously considered.
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Affiliation(s)
- Maria Galardi-Castilla
- Instituto de Investigaciones Biomédicas, Consejo Superior de Investigaciones Cientificas/Universidad Autónoma de Madrid, Madrid, Spain
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36
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Milanesio P, Arce-Rodríguez A, Muñoz A, Calles B, de Lorenzo V. Regulatory exaptation of the catabolite repression protein (Crp)-cAMP system in Pseudomonas putida. Environ Microbiol 2010; 13:324-39. [PMID: 21281420 DOI: 10.1111/j.1462-2920.2010.02331.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The genome of the soil bacterium Pseudomonas putida KT2440 encodes singular orthologues of genes crp (encoding the catabolite repression protein, Crp) and cyaA (adenylate cyclase) of Escherichia coli. The levels of cAMP formed by P. putida cells were below detection with a Dictyostelium biosensor in vivo. The cyaA(P. putida) gene was transcribed in vivo but failed to complement the lack of maltose consumption of a cyaA mutant of E. coli, thereby indicating that cyaA(P. putida) was poorly translated or rendered non-functional in the heterologous host. Yet, generation of cAMP by CyaA(P. putida) could be verified by expressing the cyaA(P. putida) gene in a hypersensitive E. coli strain. On the other hand, the crp(P. putida) gene restored the metabolic capacities of an equivalent crp mutant of E. coli, but not in a double crp/cyaA strain, suggesting that the ability to regulate such functions required cAMP. In order to clarify the breadth of the Crp/cAMP system in P. putida, crp and cyaA mutants were generated and passed through a battery of phenotypic tests for recognition of gross metabolic properties and stress-endurance abilities. These assays revealed that the loss of each gene led in most (but not all) cases to the same phenotypic behaviour, indicating a concerted functionality. Unexpectedly, none of the mutations affected the panel of carbon compounds that can be used by P. putida as growth substrates, the mutants being impaired only in the use of various dipeptides as N sources. Furthermore, the lack of crp or cyaA had little influence on the gross growth fingerprinting of the cells. The poor physiological profile of the Crp-cAMP system of P. putida when compared with E. coli exposes a case of regulatory exaptation, i.e. the process through which a property evolved for a particular function is co-opted for a new use.
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Affiliation(s)
- Paola Milanesio
- Systems Biology Program, Centro Nacional de Biotecnología-CSIC, Campus de Cantoblanco, Madrid 28049, Spain
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37
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Abstract
The ability of cells to migrate directionally in gradients of chemoattractant is a fundamental biological response that is essential for the survival of the social amoebae Dictyostelium discoideum. In Dictyostelium, cAMP is the most potent chemoattractant and the detection, synthesis, and degradation of cAMP is exquisitely regulated. Interestingly, as Dictyostelium cells migrate directionally, they do so in a head-to-tail fashion, forming characteristic streams. This group behavior is acquired through the relay of the cAMP signals to neighboring cells. This chapter describes experimental procedures used to obtain synchronized populations of chemotactically competent cells and to assess their streaming behavior. In addition, we provide a detailed account of the method used to measure the ability of chemoattractants to directly stimulate adenylyl cyclase activity. Together, these techniques provide a way to combine cell biological and biochemical approaches to the study of signal relay.
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Affiliation(s)
- Paul W Kriebel
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, USA
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38
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Garcia GL, Rericha EC, Heger CD, Goldsmith PK, Parent CA. The group migration of Dictyostelium cells is regulated by extracellular chemoattractant degradation. Mol Biol Cell 2009; 20:3295-304. [PMID: 19477920 DOI: 10.1091/mbc.e09-03-0223] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Starvation of Dictyostelium induces a developmental program in which cells form an aggregate that eventually differentiates into a multicellular structure. The aggregate formation is mediated by directional migration of individual cells that quickly transition to group migration in which cells align in a head-to-tail manner to form streams. Cyclic AMP acts as a chemoattractant and its production, secretion, and degradation are highly regulated. A key protein is the extracellular phosphodiesterase PdsA. In this study we examine the role and localization of PdsA during chemotaxis and streaming. We find that pdsA(-) cells respond chemotactically to a narrower range of chemoattractant concentrations compared with wild-type (WT) cells. Moreover, unlike WT cells, pdsA(-) cells do not form streams at low cell densities and form unusual thick and transient streams at high cell densities. We find that the intracellular pool of PdsA is localized to the endoplasmic reticulum, which may provide a compartment for storage and secretion of PdsA. Because we find that cAMP synthesis is normal in cells lacking PdsA, we conclude that signal degradation regulates the external cAMP gradient field generation and that the group migration behavior of these cells is compromised even though their signaling machinery is intact.
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Affiliation(s)
- Gene L Garcia
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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Flynt AS, Thatcher EJ, Burkewitz K, Li N, Liu Y, Patton JG. miR-8 microRNAs regulate the response to osmotic stress in zebrafish embryos. ACTA ACUST UNITED AC 2009; 185:115-27. [PMID: 19332888 PMCID: PMC2700511 DOI: 10.1083/jcb.200807026] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
MicroRNAs (miRNAs) are highly conserved small RNAs that act as translational regulators of gene expression, exerting their influence by selectively targeting mRNAs bearing complementary sequence elements. These RNAs function in diverse aspects of animal development and physiology. Because of an ability to act as rapid responders at the level of translation, miRNAs may also influence stress response. In this study, we show that the miR-8 family of miRNAs regulates osmoregulation in zebrafish embryos. Ionocytes, which are a specialized cell type scattered throughout the epidermis, are responsible for pH and ion homeostasis during early development before gill formation. The highly conserved miR-8 family is expressed in ionocytes and enables precise control of ion transport by modulating the expression of Nherf1, which is a regulator of apical trafficking of transmembrane ion transporters. Ultimately, disruption of miR-8 family member function leads to an inability to respond to osmotic stress and blocks the ability to properly traffic and/or cluster transmembrane glycoproteins at the apical surface of ionocytes.
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Affiliation(s)
- Alex S Flynt
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA
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40
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The Evolution of Morphogenetic Signalling in Social Amoebae. Evol Biol 2009. [DOI: 10.1007/978-3-642-00952-5_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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41
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Abstract
The ability of cells to migrate in response to external cues, a process known as chemotaxis, is a fundamental phenomenon in biology. It is exhibited by a wide variety of cell types in the context of embryogenesis, angiogenesis, inflammation, wound healing and many other complex physiological processes. Here, we discuss the signals that control the directed migration of the social amoebae Dictyostelium discoideum both as single cells and in the context of group migration. This multi-cellular organism has served as an excellent model system to decipher amoeboid-like leukocyte migration and has played a key role in establishing signalling paradigms in the chemotaxis field. We envision that Dictyostelium will continue to bring forward basic knowledge as we seek to understand the mechanisms regulating group cell migration.
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Affiliation(s)
- G L Garcia
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-4255, USA
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42
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Affiliation(s)
- Anna Bagorda
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda MD 20892-4256, USA
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Arya R, Aslam S, Gupta S, Bora RS, Vijayakrishnan L, Gulati P, Naithani S, Mukherjee S, Dastidar S, Bhattacharya A, Saini KS. Production and characterization of pharmacologically active recombinant human phosphodiesterase 4B in Dictyostelium discoideum. Biotechnol J 2008; 3:938-47. [PMID: 18348140 DOI: 10.1002/biot.200700256] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Phosphodiesterase 4B (PDE4B) is an important therapeutic target for asthma and chronic obstructive pulmonary disease. To identify PDE4 subtype-specific compounds using high-throughput assays, full-length recombinant PDE4 proteins are needed in bulk quantity. In the present study, full-length human PDE4B2 was expressed in the cellular slime mould Dictyostelium discoideum (Dd). A cell density of 2 x 10(7) cells/mL was obtained and up to 1 mg/L recombinant PDE4B2 was purified through Ni-NTA affinity chromatography. The expressed protein was soluble and its activity was comparable to PDE4B2 protein expressed in mammalian cells (K(m)=1.7 microM). The functional significance of the Dd expression system is supported by the demonstration that, in concert with proteins expressed in mammalian systems, there are no major changes in the affinity for PDE4B2 inhibitors and substrates. These findings thus provide the first evidence that Dd can be utilized for the expression and purification of functionally active full-length human PDE4B2 in large amounts required for high-throughput screening of pharmacologically active compounds against this therapeutic target.
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Affiliation(s)
- Ranjana Arya
- Department of Biotechnology and Bioinformatics, Ranbaxy Research laboratories, Gurgaon, Haryana, India.
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Purinergic-mediated Ca2+ influx in Dictyostelium discoideum. Cell Calcium 2008; 44:567-79. [PMID: 18486207 PMCID: PMC2658738 DOI: 10.1016/j.ceca.2008.04.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2008] [Revised: 03/31/2008] [Accepted: 04/06/2008] [Indexed: 11/22/2022]
Abstract
The presence of five P2X-like genes (p2xA–E) in Dictyostelium suggests that nucleotides other than cAMP may act as extracellular signalling molecules in this model eukaryote. However, p2xA was found to have an exclusively intracellular localisation making it unclear whether Dictyostelium utilise P2 receptors in a manner analogous to vertebrates. Using an apoaequorin expressing strain we show here that Dictyostelium do possess cell surface P2 receptors that facilitate Ca2+ influx in response to extracellular ATP and ADP (EC50 = 7.5 μM and 6.1 μM, respectively). Indicative of P2X receptor activation, responses were rapid reaching peak within 2.91 ± 0.04 s, required extracellular Ca2+, were inhibited by Gd3+, modified by extracellular pH and were not affected by deletion of either the single Gβ or iplA genes. Responses also remained unaffected by disruption of p2xA or p2xE showing that these genes are not involved. Cu2+ and Zn2+ inhibited purine-evoked Ca2+ influx with IC50 values of 0.9 and 6.3 μM, respectively. 300 μM Zn2+ completely abolished the initial large rapid rise in intracellular Ca2+ revealing the presence of an additional smaller, slower P2Y-like response. The existence of P2 receptors in Dictyostelium makes this organism a valuable model to explore fundamental aspects of purinergic signalling.
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Shpakov AO, Pertseva MN. Chapter 4 Signaling Systems of Lower Eukaryotes and Their Evolution. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2008; 269:151-282. [DOI: 10.1016/s1937-6448(08)01004-6] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Abstract
A fundamental goal of biology is to understand how novel phenotypes evolved through changes in existing genes. The Dictyostelia or social amoebas represent a simple form of multicellularity, where starving cells aggregate to build fruiting structures. This review summarizes efforts to provide a framework for investigating the genetic changes that generated novel morphologies in the Dictyostelia. The foundation is a recently constructed molecular phylogeny of the Dictyostelia, which was used to examine trends in the evolution of novel forms and in the divergence of genes that shape these forms. There is a major trend towards the formation of large unbranched fruiting bodies, which is correlated with the use of cyclic AMP (cAMP) as a secreted signal to coordinate cell aggregation. The role of cAMP in aggregation arose through co‐option of a pathway that originally acted to coordinate fruiting body formation. The genotypic changes that caused this innovation and the role of dynamic cAMP signaling in defining fruiting body size and pattern throughout social amoeba evolution are discussed. BioEssays 29:635–644, 2007. © 2007 Wiley Periodicals, Inc.
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Affiliation(s)
- Pauline Schaap
- College of Life Sciences, University of Dundee, MSI/WTB/JBC complex, Dow Street, Dundee DD1 5EH, UK.
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Shpakov AO. Structure-functional organization of adenylyl cyclases of unicellular eukaryotes and molecular mechanisms of their regulation. ACTA ACUST UNITED AC 2007. [DOI: 10.1134/s1990519x07020010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Bader S, Kortholt A, Van Haastert P. Seven Dictyostelium discoideum phosphodiesterases degrade three pools of cAMP and cGMP. Biochem J 2007; 402:153-61. [PMID: 17040207 PMCID: PMC1783984 DOI: 10.1042/bj20061153] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The Dictyostelium discoideum genome uncovers seven cyclic nucleotide PDEs (phosphodiesterases), of which six have been characterized previously and the seventh is characterized in the present paper. Three enzymes belong to the ubiquitous class I PDEs, common in all eukaryotes, whereas four enzymes belong to the rare class II PDEs that are present in bacteria and lower eukaryotes. Since all D. discoideum PDEs are now characterized we have calculated the contribution of each enzyme in the degradation of the three important pools of cyclic nucleotides: (i) extracellular cAMP that induces chemotaxis during aggregation and differentiation in slugs; (ii) intracellular cAMP that mediates development; and (iii) intracellular cGMP that mediates chemotaxis. It appears that each cyclic nucleotide pool is degraded by a combination of enzymes that have different affinities, allowing a broad range of substrate concentrations to be degraded with first-order kinetics. Extracellular cAMP is degraded predominantly by the class II high-affinity enzyme DdPDE1 and its close homologue DdPDE7, and in the multicellular stage also by the low-affinity transmembrane class I enzyme DdPDE4. Intracellular cAMP is degraded by the DdPDE2, a class I enzyme regulated by histidine kinase/phospho-relay, and by the cAMP-/cGMP-stimulated class II DdPDE6. Finally, basal intracellular cGMP is degraded predominantly by the high-affinity class I DdPDE3, while the elevated cGMP levels that arise after receptor stimulation are degraded predominantly by a cGMP-stimulated cGMP-specific class II DdPDE5. The analysis shows that the combination of enzymes is tuned to keep the concentration and lifetime of the substrate within a functional range.
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Affiliation(s)
- Sonya Bader
- Department of Molecular Cell Biology, University of Groningen, Kerklaan 30, 9751NN, Haren, The Netherlands
| | - Arjan Kortholt
- Department of Molecular Cell Biology, University of Groningen, Kerklaan 30, 9751NN, Haren, The Netherlands
| | - Peter J. M. Van Haastert
- Department of Molecular Cell Biology, University of Groningen, Kerklaan 30, 9751NN, Haren, The Netherlands
- To whom correspondence should be addressed (email )
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Muramoto T, Kuwayama H, Kobayashi K, Urushihara H. A stress response kinase, KrsA, controls cAMP relay during the early development of Dictyostelium discoideum. Dev Biol 2007; 305:77-89. [PMID: 17362909 DOI: 10.1016/j.ydbio.2007.01.039] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2006] [Revised: 01/29/2007] [Accepted: 01/31/2007] [Indexed: 11/19/2022]
Abstract
Solitary amoebae of Dictyostelium discoideum are frequently exposed to stressful conditions in nature, and their multicellular development is one response to environmental stress. Here we analyzed an aggregation stage abundant gene, krsA, homologous to human krs1 (kinase responsive to stress 1) to understand the mechanisms for the initiation of development and cell fate determination. The krsA- cells exhibited reduced viability under hyperosmotic conditions. They produced smaller aggregates on membrane filters and did not form aggregation streams on a plastic surface under submerged starvation conditions, but were normal in sexual development. During early asexual development, the expression of cAMP-related genes peaked earlier in the knockout mutants. Neither cAMP oscillation in starved cells nor an increase in the cAMP level following osmotic stress was observed in krsA-. The nuclear export signal, as well as the kinase domain, in KrsA was necessary for stream formation. These results strongly suggest that krsA is involved in cAMP relay, and that signaling pathways for multicellular development have evolved in unison with the stress response.
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Affiliation(s)
- Tetsuya Muramoto
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8572, Japan
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Alvarez-Curto E, Weening K, Schaap P. Pharmacological profiling of the Dictyostelium adenylate cyclases ACA, ACB and ACG. Biochem J 2007; 401:309-16. [PMID: 16952277 PMCID: PMC1698679 DOI: 10.1042/bj20060880] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Intracellular and secreted cAMPs play crucial roles in controlling cell movement and gene regulation throughout development of the social amoeba Dictyostelium discoideum. cAMP is produced by three structurally distinct ACs (adenylate cyclases), ACA, ACG and ACB, which have distinctive but overlapping patterns of expression and, as concluded from gene disruption studies, seemingly overlapping functions. In addition to gene disruption, acute pharmacological abrogation of protein activity can be a powerful tool to identify the protein's role in the biology of the organism. We analysed the effects of a range of compounds on the activity of ACA, ACB and ACG to identify enzyme-specific modulators. Caffeine, which was previously used to specifically block ACA function, also inhibited cAMP accumulation by ACB and ACG. IPA (2',3'-O-isopropylidene adenosine) specifically inhibits ACA when measured in intact cells, without affecting ACB or ACG. All three enzymes are inhibited by the P-site inhibitor DDA (2',5'-dideoxyadenosine) when assayed in cell lysates, but not in intact cells. Tyrphostin A25 [alpha-cyano-(3,4,5-trihydroxy)cinnamonitrile] and SQ22536 [9-(tetrahydro-2'-furyl)adenine] proved to be effective and specific inhibitors for ACG and ACA respectively. Both compounds acted directly on enzyme activity assayed in cell lysates, but only SQ22536 was also a specific inhibitor when added to intact cells.
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Affiliation(s)
| | - Karin E. Weening
- School of Life Sciences, University of Dundee, Dundee, Scotland, U.K
| | - Pauline Schaap
- School of Life Sciences, University of Dundee, Dundee, Scotland, U.K
- To whom correspondence should be addressed, at MSI/WTB/JBC Complex, Dow Street, Dundee DD1 5EH, Scotland, U.K. (email )
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