1
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Smith SF, Islam AFMT, Alimukhamedov S, Weiss ET, Charest PG. Molecular determinants of Ras-mTORC2 signaling. J Biol Chem 2024; 300:107423. [PMID: 38815864 PMCID: PMC11255897 DOI: 10.1016/j.jbc.2024.107423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2024] [Revised: 05/16/2024] [Accepted: 05/20/2024] [Indexed: 06/01/2024] Open
Abstract
Recent research has identified the mechanistic Target of Rapamycin Complex 2 (mTORC2) as a conserved direct effector of Ras proteins. While previous studies suggested the involvement of the Switch I (SWI) effector domain of Ras in binding mTORC2 components, the regulation of the Ras-mTORC2 pathway is not entirely understood. In Dictyostelium, mTORC2 is selectively activated by the Ras protein RasC, and the RasC-mTORC2 pathway then mediates chemotaxis to cAMP and cellular aggregation by regulating the actin cytoskeleton and promoting cAMP signal relay. Here, we investigated the role of specific residues in RasC's SWI, C-terminal allosteric domain, and hypervariable region (HVR) related to mTORC2 activation. Interestingly, our results suggest that RasC SWI residue A31, which was previously implicated in RasC-mediated aggregation, regulates RasC's specific activation by the Aimless RasGEF. On the other hand, our investigation identified a crucial role for RasC SWI residue T36, with secondary contributions from E38 and allosteric domain residues. Finally, we found that conserved basic residues and the adjacent prenylation site in the HVR, which are crucial for RasC's membrane localization, are essential for RasC-mTORC2 pathway activation by allowing for both RasC's own cAMP-induced activation and its subsequent activation of mTORC2. Therefore, our findings revealed new determinants of RasC-mTORC2 pathway specificity in Dictyostelium, contributing to a deeper understanding of Ras signaling regulation in eukaryotic cells.
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Affiliation(s)
- Stephen F Smith
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona, USA
| | - A F M Tariqul Islam
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona, USA
| | | | - Ethan T Weiss
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona, USA
| | - Pascale G Charest
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona, USA; Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona, USA; University of Arizona Cancer Center, Tucson, Arizona, USA.
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2
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Allan CY, Sanislav O, Fisher PR. Polycystin-2 Mediated Calcium Signalling in the Dictyostelium Model for Autosomal Dominant Polycystic Kidney Disease. Cells 2024; 13:610. [PMID: 38607049 PMCID: PMC11012017 DOI: 10.3390/cells13070610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 03/26/2024] [Accepted: 03/27/2024] [Indexed: 04/13/2024] Open
Abstract
Autosomal dominant polycystic kidney disease (ADPKD) occurs when the proteins Polycystin-1 (PC1, PKD1) and Polycystin-2 (PC2, PKD2) contain mutations. PC1 is a large membrane receptor that can interact and form a complex with the calcium-permeable cation channel PC2. This complex localizes to the plasma membrane, primary cilia and ER. Dysregulated calcium signalling and consequential alterations in downstream signalling pathways in ADPKD are linked to cyst formation and expansion; however, it is not completely understood how PC1 and PC2 regulate calcium signalling. We have studied Polycystin-2 mediated calcium signalling in the model organism Dictyostelium discoideum by overexpressing and knocking down the expression of the endogenous Polycystin-2 homologue, Polycystin-2. Chemoattractant-stimulated cytosolic calcium response magnitudes increased and decreased in overexpression and knockdown strains, respectively, and analysis of the response kinetics indicates that Polycystin-2 is a significant contributor to the control of Ca2+ responses. Furthermore, basal cytosolic calcium levels were reduced in Polycystin-2 knockdown transformants. These alterations in Ca2+ signalling also impacted other downstream Ca2+-sensitive processes including growth rates, endocytosis, stalk cell differentiation and spore viability, indicating that Dictyostelium is a useful model to study Polycystin-2 mediated calcium signalling.
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Affiliation(s)
| | | | - Paul R. Fisher
- Department of Microbiology, Anatomy, Physiology and Pharmacology, La Trobe University, Bundoora, Melbourne, VIC 3086, Australia; (C.Y.A.)
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3
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Rojas D, Marcoleta AE, Gálvez-Silva M, Varas MA, Díaz M, Hernández M, Vargas C, Nourdin-Galindo G, Koch E, Saldivia P, Vielma J, Gan YH, Chen Y, Guiliani N, Chávez FP. Inorganic Polyphosphate Affects Biofilm Assembly, Capsule Formation, and Virulence of Hypervirulent ST23 Klebsiella pneumoniae. ACS Infect Dis 2024; 10:606-623. [PMID: 38205780 DOI: 10.1021/acsinfecdis.3c00509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2024]
Abstract
The emergence of hypervirulent Klebsiella pneumoniae (hvKP) strains poses a significant threat to public health due to high mortality rates and propensity to cause severe community-acquired infections in healthy individuals. The ability to form biofilms and produce a protective capsule contributes to its enhanced virulence and is a significant challenge to effective antibiotic treatment. Polyphosphate kinase 1 (PPK1) is an enzyme responsible for inorganic polyphosphate synthesis and plays a vital role in regulating various physiological processes in bacteria. In this study, we investigated the impact of polyP metabolism on the biofilm and capsule formation and virulence traits in hvKP using Dictyostelium discoideum amoeba as a model host. We found that the PPK1 null mutant was impaired in biofilm and capsule formation and showed attenuated virulence in D. discoideum compared to the wild-type strain. We performed a proteomic analysis to gain further insights into the underlying molecular mechanism. The results revealed that the PPK1 mutant had a differential expression of proteins involved in capsule synthesis (Wzi-Ugd), biofilm formation (MrkC-D-H), synthesis of the colibactin genotoxin precursor (ClbB), as well as proteins associated with the synthesis and modification of lipid A (ArnB-LpxC-PagP). These proteomic findings corroborate the phenotypic observations and indicate that the PPK1 mutation is associated with impaired biofilm and capsule formation and attenuated virulence in hvKP. Overall, our study highlights the importance of polyP synthesis in regulating extracellular biomolecules and virulence in K. pneumoniae and provides insights into potential therapeutic targets for treating K. pneumoniae infections.
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Affiliation(s)
- Diego Rojas
- Laboratorio de Microbiología de Sistemas, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago CP 7800003, Chile
| | - Andrés E Marcoleta
- Grupo de Microbiología Integrativa, Laboratorio de Biología Estructural y Molecular, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago CP 7800003, Chile
| | - Matías Gálvez-Silva
- Laboratorio de Microbiología de Sistemas, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago CP 7800003, Chile
- Grupo de Microbiología Integrativa, Laboratorio de Biología Estructural y Molecular, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago CP 7800003, Chile
| | - Macarena A Varas
- Laboratorio de Microbiología de Sistemas, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago CP 7800003, Chile
- Grupo de Microbiología Integrativa, Laboratorio de Biología Estructural y Molecular, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago CP 7800003, Chile
| | - Mauricio Díaz
- Laboratorio de Comunicación Microbiana, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago CP 7800003, Chile
| | - Mauricio Hernández
- División Biotecnología, Instituto Melisa, San Pedro de la Paz CP 9660000, Chile
| | - Cristian Vargas
- División Biotecnología, Instituto Melisa, San Pedro de la Paz CP 9660000, Chile
| | | | - Elard Koch
- División Biotecnología, Instituto Melisa, San Pedro de la Paz CP 9660000, Chile
| | - Pablo Saldivia
- División Biotecnología, Instituto Melisa, San Pedro de la Paz CP 9660000, Chile
- Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción CP 4070389, Chile
| | - Jorge Vielma
- Laboratorio de Microbiología de Sistemas, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago CP 7800003, Chile
- Grupo de Microbiología Integrativa, Laboratorio de Biología Estructural y Molecular, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago CP 7800003, Chile
| | - Yunn-Hwen Gan
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore CP 119077, Singapore
| | - Yahua Chen
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore CP 119077, Singapore
| | - Nicolás Guiliani
- Laboratorio de Comunicación Microbiana, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago CP 7800003, Chile
| | - Francisco P Chávez
- Laboratorio de Microbiología de Sistemas, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago CP 7800003, Chile
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4
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Jaiswal P, Meena NP, Chang FS, Liao XH, Kim L, Kimmel AR. An integrated, cross-regulation pathway model involving activating/adaptive and feed-forward/feed-back loops for directed oscillatory cAMP signal-relay/response during the development of Dictyostelium. Front Cell Dev Biol 2024; 11:1263316. [PMID: 38357530 PMCID: PMC10865387 DOI: 10.3389/fcell.2023.1263316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 12/19/2023] [Indexed: 02/16/2024] Open
Abstract
Self-organized and excitable signaling activities play important roles in a wide range of cellular functions in eukaryotic and prokaryotic cells. Cells require signaling networks to communicate amongst themselves, but also for response to environmental cues. Such signals involve complex spatial and temporal loops that may propagate as oscillations or waves. When Dictyostelium become starved for nutrients, cells within a localized space begin to secrete cAMP. Starved cells also become chemotactic to cAMP. cAMP signals propagate as outwardly moving waves that oscillate at ∼6 min intervals, which creates a focused territorial region for centralized cell aggregation. Proximal cells move inwardly toward the cAMP source and relay cAMP outwardly to recruit additional cells. To ensure directed inward movement and outward cAMP relay, cells go through adapted and de-adapted states for both cAMP synthesis/degradation and for directional cell movement. Although many immediate components that regulate cAMP signaling (including receptors, G proteins, an adenylyl cyclase, phosphodiesterases, and protein kinases) are known, others are only inferred. Here, using biochemical experiments coupled with gene inactivation studies, we model an integrated large, multi-component kinetic pathway involving activation, inactivation (adaptation), re-activation (re-sensitization), feed-forward, and feed-back controls to generate developmental cAMP oscillations.
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Affiliation(s)
- Pundrik Jaiswal
- Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, The National Institutes of Health, Bethesda, MD, United States
| | - Netra Pal Meena
- Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, The National Institutes of Health, Bethesda, MD, United States
| | - Fu-Sheng Chang
- Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, The National Institutes of Health, Bethesda, MD, United States
| | - Xin-Hua Liao
- Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, The National Institutes of Health, Bethesda, MD, United States
| | - Lou Kim
- Department of Biological Sciences, Florida International University, Miami, FL, United States
| | - Alan R. Kimmel
- Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, The National Institutes of Health, Bethesda, MD, United States
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5
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Putman TE, Schaper K, Matentzoglu N, Rubinetti V, Alquaddoomi F, Cox C, Caufield JH, Elsarboukh G, Gehrke S, Hegde H, Reese J, Braun I, Bruskiewich R, Cappelletti L, Carbon S, Caron A, Chan L, Chute C, Cortes K, De Souza V, Fontana T, Harris N, Hartley E, Hurwitz E, Jacobsen JB, Krishnamurthy M, Laraway B, McLaughlin J, McMurry J, Moxon ST, Mullen K, O’Neil S, Shefchek K, Stefancsik R, Toro S, Vasilevsky N, Walls R, Whetzel P, Osumi-Sutherland D, Smedley D, Robinson P, Mungall C, Haendel M, Munoz-Torres M. The Monarch Initiative in 2024: an analytic platform integrating phenotypes, genes and diseases across species. Nucleic Acids Res 2024; 52:D938-D949. [PMID: 38000386 PMCID: PMC10767791 DOI: 10.1093/nar/gkad1082] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 10/21/2023] [Accepted: 11/02/2023] [Indexed: 11/26/2023] Open
Abstract
Bridging the gap between genetic variations, environmental determinants, and phenotypic outcomes is critical for supporting clinical diagnosis and understanding mechanisms of diseases. It requires integrating open data at a global scale. The Monarch Initiative advances these goals by developing open ontologies, semantic data models, and knowledge graphs for translational research. The Monarch App is an integrated platform combining data about genes, phenotypes, and diseases across species. Monarch's APIs enable access to carefully curated datasets and advanced analysis tools that support the understanding and diagnosis of disease for diverse applications such as variant prioritization, deep phenotyping, and patient profile-matching. We have migrated our system into a scalable, cloud-based infrastructure; simplified Monarch's data ingestion and knowledge graph integration systems; enhanced data mapping and integration standards; and developed a new user interface with novel search and graph navigation features. Furthermore, we advanced Monarch's analytic tools by developing a customized plugin for OpenAI's ChatGPT to increase the reliability of its responses about phenotypic data, allowing us to interrogate the knowledge in the Monarch graph using state-of-the-art Large Language Models. The resources of the Monarch Initiative can be found at monarchinitiative.org and its corresponding code repository at github.com/monarch-initiative/monarch-app.
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Affiliation(s)
- Tim E Putman
- Department of Biomedical Informatics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Kevin Schaper
- Department of Biomedical Informatics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | | | - Vincent P Rubinetti
- Department of Biomedical Informatics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Faisal S Alquaddoomi
- Department of Biomedical Informatics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Corey Cox
- Department of Biomedical Informatics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - J Harry Caufield
- Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Glass Elsarboukh
- Department of Biomedical Informatics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Sarah Gehrke
- Department of Biomedical Informatics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Harshad Hegde
- Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Justin T Reese
- Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Ian Braun
- Data Collaboration Center, Critical Path Institute, Tucson, AZ 85718, USA
| | | | | | - Seth Carbon
- Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Anita R Caron
- European Bioinformatics Institute (EMBL-EBI), Hinxton CB10 1SD, UK
| | - Lauren E Chan
- College of Public Health and Human Sciences, Oregon State University, Corvallis, OR 97331, USA
| | - Christopher G Chute
- Schools of Medicine, Public Health, and Nursing, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Katherina G Cortes
- Department of Biomedical Informatics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | | | - Tommaso Fontana
- Dipartimento di Informatica, Università degli Studi di Milano Statale, Milano, Italy
| | - Nomi L Harris
- Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Emily L Hartley
- Data Collaboration Center, Critical Path Institute, Tucson, AZ 85718, USA
| | - Eric Hurwitz
- Department of Biomedical Informatics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Julius O B Jacobsen
- William Harvey Research Institute, Queen Mary University of London, London EC1M 6BQ, UK
| | - Madan Krishnamurthy
- Department of Biomedical Informatics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Bryan J Laraway
- Department of Biomedical Informatics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | | | - Julie A McMurry
- Department of Biomedical Informatics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Sierra A T Moxon
- Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Kathleen R Mullen
- Department of Biomedical Informatics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Shawn T O’Neil
- Department of Biomedical Informatics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Kent A Shefchek
- Department of Biomedical Informatics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Ray Stefancsik
- European Bioinformatics Institute (EMBL-EBI), Hinxton CB10 1SD, UK
| | - Sabrina Toro
- Department of Biomedical Informatics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | | | - Ramona L Walls
- Data Collaboration Center, Critical Path Institute, Tucson, AZ 85718, USA
| | - Patricia L Whetzel
- Department of Biomedical Informatics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | | | - Damian Smedley
- William Harvey Research Institute, Queen Mary University of London, London EC1M 6BQ, UK
| | - Peter N Robinson
- The Jackson Laboratory for Genomic Medicine, Farmington, CT 6032, USA
| | - Christopher J Mungall
- Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Melissa A Haendel
- Department of Biomedical Informatics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Monica C Munoz-Torres
- Department of Biomedical Informatics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
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6
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Ecke M, Gerisch G. Chemotaxis of Large Multinucleate Cells of Dictyostelium Produced by Electric-Pulse Induced Fusion. Methods Mol Biol 2024; 2828:147-157. [PMID: 39147976 DOI: 10.1007/978-1-0716-4023-4_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/17/2024]
Abstract
Normal-sized cells of Dictyostelium build up a front-tail polarity when they respond to a gradient of chemoattractant. To challenge the polarity-generating system, cells are fused to study the chemotactic response of oversized cells that extend multiple fronts toward the source of attractant. An aspect that can be explored in these cells is the relationship of spontaneously generated actin waves to actin reorganization in response to chemoattractant.
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Affiliation(s)
- Mary Ecke
- Max Planck Institute of Biochemistry, Martinsried, Germany.
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7
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Takashima JA, Woroniecka HA, Charest PG. APEX2-Mediated Proximity Protein Labeling in Dictyostelium. Methods Mol Biol 2024; 2814:119-131. [PMID: 38954202 DOI: 10.1007/978-1-0716-3894-1_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/04/2024]
Abstract
Largely due to its simplicity, while being more like human cells compared to other experimental models, Dictyostelium continues to be of great use to discover basic molecular mechanisms and signaling pathways underlying evolutionarily conserved biological processes. However, the identification of new protein interactions implicated in signaling pathways can be particularly challenging in Dictyostelium due to its extremely fast signaling kinetics coupled with the dynamic nature of signaling protein interactions. Recently, the proximity labeling method using engineered ascorbic acid peroxidase 2 (APEX2) in mammalian cells was shown to allow the detection of weak and/or transient protein interactions and also to obtain spatial and temporal resolution. Here, we describe a protocol for successfully using the APEX2-proximity labeling method in Dictyostelium. Coupled with the identification of the labeled proteins by mass spectrometry, this method expands Dictyostelium's proteomics toolbox and should be widely useful for identifying interacting partners involved in a variety of biological processes in Dictyostelium.
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Affiliation(s)
- Jamie A Takashima
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, USA
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Helena A Woroniecka
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, USA
| | - Pascale G Charest
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, USA.
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ, USA.
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8
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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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9
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Heidarian Y, Tourigny JP, Fasteen TD, Mahmoudzadeh NH, Hurlburt AJ, Nemkov T, Reisz JA, D’Alessandro A, Tennessen JM. Metabolomic analysis of Drosophila melanogaster larvae lacking pyruvate kinase. G3 (BETHESDA, MD.) 2023; 14:jkad228. [PMID: 37792629 PMCID: PMC10755183 DOI: 10.1093/g3journal/jkad228] [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: 06/02/2023] [Revised: 06/02/2023] [Accepted: 09/24/2023] [Indexed: 10/06/2023]
Abstract
Pyruvate kinase (Pyk) is a rate-limiting enzyme that catalyzes the final metabolic reaction in glycolysis. The importance of this enzyme, however, extends far beyond ATP production, as Pyk is also known to regulate tissue growth, cell proliferation, and development. Studies of this enzyme in Drosophila melanogaster are complicated by the fact that the fly genome encodes 6 Pyk paralogs whose functions remain poorly defined. To address this issue, we used sequence distance and phylogenetic approaches to demonstrate that the gene Pyk encodes the enzyme most similar to the mammalian Pyk orthologs, while the other 5 Drosophila Pyk paralogs have significantly diverged from the canonical enzyme. Consistent with this observation, metabolomic studies of 2 different Pyk mutant strains revealed that larvae lacking Pyk exhibit a severe block in glycolysis, with a buildup of glycolytic intermediates upstream of pyruvate. However, our analysis also unexpectedly reveals that pyruvate levels are unchanged in Pyk mutants, indicating that larval metabolism maintains pyruvate pool size despite severe metabolic limitations. Consistent with our metabolomic findings, a complementary RNA-seq analysis revealed that genes involved in lipid metabolism and protease activity are elevated in Pyk mutants, again indicating that loss of this glycolytic enzyme induces compensatory changes in other aspects of metabolism. Overall, our study provides both insight into how Drosophila larval metabolism adapts to disruption of glycolytic metabolism as well as immediate clinical relevance, considering that Pyk deficiency is the most common congenital enzymatic defect in humans.
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Affiliation(s)
- Yasaman Heidarian
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - Jason P Tourigny
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - Tess D Fasteen
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | | | | | - Travis Nemkov
- Department of Biochemistry and Molecular Genetics, Anschutz Medical Campus, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Julie A Reisz
- Department of Biochemistry and Molecular Genetics, Anschutz Medical Campus, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Angelo D’Alessandro
- Department of Biochemistry and Molecular Genetics, Anschutz Medical Campus, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Jason M Tennessen
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
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10
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Banerjee T, Matsuoka S, Biswas D, Miao Y, Pal DS, Kamimura Y, Ueda M, Devreotes PN, Iglesias PA. A dynamic partitioning mechanism polarizes membrane protein distribution. Nat Commun 2023; 14:7909. [PMID: 38036511 PMCID: PMC10689845 DOI: 10.1038/s41467-023-43615-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 11/14/2023] [Indexed: 12/02/2023] Open
Abstract
The plasma membrane is widely regarded as the hub of the numerous signal transduction activities. Yet, the fundamental biophysical mechanisms that spatiotemporally compartmentalize different classes of membrane proteins remain unclear. Using multimodal live-cell imaging, here we first show that several lipid-anchored membrane proteins are consistently depleted from the membrane regions where the Ras/PI3K/Akt/F-actin network is activated. The dynamic polarization of these proteins does not depend upon the F-actin-based cytoskeletal structures, recurring shuttling between membrane and cytosol, or directed vesicular trafficking. Photoconversion microscopy and single-molecule measurements demonstrate that these lipid-anchored molecules have substantially dissimilar diffusion profiles in different regions of the membrane which enable their selective segregation. When these diffusion coefficients are incorporated into an excitable network-based stochastic reaction-diffusion model, simulations reveal that the altered affinity mediated selective partitioning is sufficient to drive familiar propagating wave patterns. Furthermore, normally uniform integral and lipid-anchored membrane proteins partition successfully when membrane domain-specific peptides are optogenetically recruited to them. We propose "dynamic partitioning" as a new mechanism that can account for large-scale compartmentalization of a wide array of lipid-anchored and integral membrane proteins during various physiological processes where membrane polarizes.
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Affiliation(s)
- Tatsat Banerjee
- Department of Cell Biology and Center for Cell Dynamics, School of Medicine, Johns Hopkins University, Baltimore, MD, USA.
- Department of Chemical and Biomolecular Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore, MD, USA.
| | - Satomi Matsuoka
- Laboratory for Cell Signaling Dynamics, RIKEN Center for Biosystems Dynamics Research, Suita, Osaka, Japan
- Laboratory of Single Molecule Biology, Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
| | - Debojyoti Biswas
- Department of Electrical and Computer Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Yuchuan Miao
- Department of Cell Biology and Center for Cell Dynamics, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
- Department of Biological Chemistry, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Dhiman Sankar Pal
- Department of Cell Biology and Center for Cell Dynamics, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Yoichiro Kamimura
- Laboratory for Cell Signaling Dynamics, RIKEN Center for Biosystems Dynamics Research, Suita, Osaka, Japan
| | - Masahiro Ueda
- Laboratory for Cell Signaling Dynamics, RIKEN Center for Biosystems Dynamics Research, Suita, Osaka, Japan
- Laboratory of Single Molecule Biology, Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
| | - Peter N Devreotes
- Department of Cell Biology and Center for Cell Dynamics, School of Medicine, Johns Hopkins University, Baltimore, MD, USA.
- Department of Biological Chemistry, School of Medicine, Johns Hopkins University, Baltimore, MD, USA.
| | - Pablo A Iglesias
- Department of Cell Biology and Center for Cell Dynamics, School of Medicine, Johns Hopkins University, Baltimore, MD, USA.
- Department of Electrical and Computer Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore, MD, USA.
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11
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Allcroft TJ, Duong JT, Skardal PS, Kovarik ML. Microfluidic single-cell measurements of oxidative stress as a function of cell cycle position. Anal Bioanal Chem 2023; 415:6481-6490. [PMID: 37682313 DOI: 10.1007/s00216-023-04924-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 07/24/2023] [Accepted: 08/28/2023] [Indexed: 09/09/2023]
Abstract
Single-cell measurements routinely demonstrate high levels of variation between cells, but fewer studies provide insight into the analytical and biological sources of this variation. This is particularly true of chemical cytometry, in which individual cells are lysed and their contents separated, compared to more established single-cell measurements of the genome and transcriptome. To characterize population-level variation and its sources, we analyzed oxidative stress levels in 1278 individual Dictyostelium discoideum cells as a function of exogenous stress level and cell cycle position. Cells were exposed to varying levels of oxidative stress via singlet oxygen generation using the photosensitizer Rose Bengal. Single-cell data reproduced the dose-response observed in ensemble measurements by CE-LIF, superimposed with high levels of heterogeneity. Through experiments and data analysis, we explored possible biological sources of this heterogeneity. No trend was observed between population variation and oxidative stress level, but cell cycle position was a major contributor to heterogeneity in oxidative stress. Cells synchronized to the same stage of cell division were less heterogeneous than unsynchronized cells (RSD of 37-51% vs 93%), and mitotic cells had higher levels of reactive oxygen species than interphase cells. While past research has proposed changes in cell size during the cell cycle as a source of biological noise, the measurements presented here use an internal standard to normalize for effects of cell volume, suggesting a more complex contribution of cell cycle to heterogeneity of oxidative stress.
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12
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Rahman RJ, Rijal R, Jing S, Chen TA, Ismail I, Gomer RH. Polyphosphate uses mTOR, pyrophosphate, and Rho GTPase components to potentiate bacterial survival in Dictyostelium. mBio 2023; 14:e0193923. [PMID: 37754562 PMCID: PMC10653871 DOI: 10.1128/mbio.01939-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 07/31/2023] [Indexed: 09/28/2023] Open
Abstract
IMPORTANCE Although most bacteria are quickly killed after phagocytosis by a eukaryotic cell, some pathogenic bacteria escape death after phagocytosis. Pathogenic Mycobacterium species secrete polyP, and the polyP is necessary for the bacteria to prevent their killing after phagocytosis. Conversely, exogenous polyP prevents the killing of ingested bacteria that are normally killed after phagocytosis by human macrophages and the eukaryotic microbe Dictyostelium discoideum. This suggests the possibility that in these cells, a signal transduction pathway is used to sense polyP and prevent killing of ingested bacteria. In this report, we identify key components of the polyP signal transduction pathway in D. discoideum. In cells lacking these components, polyP is unable to inhibit killing of ingested bacteria. The pathway components have orthologs in human cells, and an exciting possibility is that pharmacologically blocking this pathway in human macrophages would cause them to kill ingested pathogens such as Mycobacterium tuberculosis.
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Affiliation(s)
- Ryan J. Rahman
- Department of Biology, Texas A&M University, College Station, Texas, USA
| | - Ramesh Rijal
- Department of Biology, Texas A&M University, College Station, Texas, USA
| | - Shiyu Jing
- Department of Biology, Texas A&M University, College Station, Texas, USA
| | - Te-An Chen
- Department of Biology, Texas A&M University, College Station, Texas, USA
| | - Issam Ismail
- Department of Biology, Texas A&M University, College Station, Texas, USA
| | - Richard H. Gomer
- Department of Biology, Texas A&M University, College Station, Texas, USA
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13
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Vines JH, Maib H, Buckley CM, Gueho A, Zhu Z, Soldati T, Murray DH, King JS. A PI(3,5)P2 reporter reveals PIKfyve activity and dynamics on macropinosomes and phagosomes. J Cell Biol 2023; 222:e202209077. [PMID: 37382666 PMCID: PMC10309190 DOI: 10.1083/jcb.202209077] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 05/12/2023] [Accepted: 06/13/2023] [Indexed: 06/30/2023] Open
Abstract
Phosphoinositide signaling lipids (PIPs) are key regulators of membrane identity and trafficking. Of these, PI(3,5)P2 is one of the least well-understood, despite key roles in many endocytic pathways including phagocytosis and macropinocytosis. PI(3,5)P2 is generated by the phosphoinositide 5-kinase PIKfyve, which is critical for phagosomal digestion and antimicrobial activity. However PI(3,5)P2 dynamics and regulation remain unclear due to lack of reliable reporters. Using the amoeba Dictyostelium discoideum, we identify SnxA as a highly selective PI(3,5)P2-binding protein and characterize its use as a reporter for PI(3,5)P2 in both Dictyostelium and mammalian cells. Using GFP-SnxA, we demonstrate that Dictyostelium phagosomes and macropinosomes accumulate PI(3,5)P2 3 min after engulfment but are then retained differently, indicating pathway-specific regulation. We further find that PIKfyve recruitment and activity are separable and that PIKfyve activation stimulates its own dissociation. SnxA is therefore a new tool for reporting PI(3,5)P2 in live cells that reveals key mechanistic details of the role and regulation of PIKfyve/PI(3,5)P2.
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Affiliation(s)
- James H. Vines
- School of Biosciences, University of Sheffield, Firth Court Western Bank, Sheffield, UK
| | - Hannes Maib
- Division of Molecular, Cell and Developmental Biology, School of Life Sciences, University of Dundee, Dundee, UK
| | - Catherine M. Buckley
- School of Biosciences, University of Sheffield, Firth Court Western Bank, Sheffield, UK
| | - Aurelie Gueho
- Department of Biochemistry, Faculty of Science, University of Geneva, Geneva, Switzerland
| | - Zhou Zhu
- School of Biosciences, University of Sheffield, Firth Court Western Bank, Sheffield, UK
| | - Thierry Soldati
- Department of Biochemistry, Faculty of Science, University of Geneva, Geneva, Switzerland
| | - David H. Murray
- Division of Molecular, Cell and Developmental Biology, School of Life Sciences, University of Dundee, Dundee, UK
| | - Jason S. King
- School of Biosciences, University of Sheffield, Firth Court Western Bank, Sheffield, UK
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14
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Velle KB, Garner RM, Beckford TK, Weeda M, Liu C, Kennard AS, Edwards M, Fritz-Laylin LK. A conserved pressure-driven mechanism for regulating cytosolic osmolarity. Curr Biol 2023; 33:3325-3337.e5. [PMID: 37478864 PMCID: PMC10529079 DOI: 10.1016/j.cub.2023.06.061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 05/24/2023] [Accepted: 06/22/2023] [Indexed: 07/23/2023]
Abstract
Controlling intracellular osmolarity is essential to all cellular life. Cells that live in hypo-osmotic environments, such as freshwater, must constantly battle water influx to avoid swelling until they burst. Many eukaryotic cells use contractile vacuoles to collect excess water from the cytosol and pump it out of the cell. Although contractile vacuoles are essential to many species, including important pathogens, the mechanisms that control their dynamics remain unclear. To identify the basic principles governing contractile vacuole function, we investigate here the molecular mechanisms of two species with distinct vacuolar morphologies from different eukaryotic lineages: the discoban Naegleria gruberi and the amoebozoan slime mold Dictyostelium discoideum. Using quantitative cell biology, we find that although these species respond differently to osmotic challenges, they both use vacuolar-type proton pumps for filling contractile vacuoles and actin for osmoregulation, but not to power water expulsion. We also use analytical modeling to show that cytoplasmic pressure is sufficient to drive water out of contractile vacuoles in these species, similar to findings from the alveolate Paramecium multimicronucleatum. These analyses show that cytoplasmic pressure is sufficient to drive contractile vacuole emptying for a wide range of cellular pressures and vacuolar geometries. Because vacuolar-type proton-pump-dependent contractile vacuole filling and pressure-dependent emptying have now been validated in three eukaryotic lineages that diverged well over a billion years ago, we propose that this represents an ancient eukaryotic mechanism of osmoregulation.
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Affiliation(s)
- Katrina B Velle
- Department of Biology, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Rikki M Garner
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Tatihana K Beckford
- Department of Biology, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Makaela Weeda
- Department of Biology, Amherst College, Amherst, MA 01002, USA
| | - Chunzi Liu
- Department of Applied Mathematics, Harvard University, Cambridge, MA 02138, USA
| | - Andrew S Kennard
- Department of Biology, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Marc Edwards
- Department of Biology, Amherst College, Amherst, MA 01002, USA
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15
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Ecke M, Prassler J, Gerisch G. Expanding ring-shaped cleavage furrows in multinucleate cells. Mol Biol Cell 2023; 34:ar27. [PMID: 36652336 PMCID: PMC10092652 DOI: 10.1091/mbc.e22-10-0487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Multinucleate cells of Dictyostelium discoideum divide usually by unilateral cleavage furrows that ingress from the cell border. Along their path into the cell, they follow regions that are rich in myosin II and cortexillin and leave out the areas around the spindle poles that are populated with microtubule asters. In cells of a D. discoideum mutant that remain spread during mitosis we observed, as a rare event, cleavage by the expansion of a hole that is initiated in the middle of the cell area and has no connection with the cell's periphery. Here we show that these ring-shaped furrows develop in two phases, the first being reversible. During the first phase, the dorsal and ventral cell cortices come in close apposition and the cell membrane detaches locally from the substrate surface. The second phase comprises formation of the hole by membrane fusion and expansion of the opening toward the border of the cell, eventually cutting the multinucleate cell into pieces. We address the three-dimensional organization of ring-shaped furrows, their interaction with lateral furrows, and their association with filamentous myosin II and cortexillin. Thus, despite their geometrical divergence, similar molecular mechanisms might link the expanding hole to the standard contractile ring.
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Affiliation(s)
- Mary Ecke
- Max Planck Institute of Biochemistry, D-82152 Martinsried, Germany
| | - Jana Prassler
- Max Planck Institute of Biochemistry, D-82152 Martinsried, Germany
| | - Günther Gerisch
- Max Planck Institute of Biochemistry, D-82152 Martinsried, Germany
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16
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Takashima JA, Woroniecka HA, Charest PG. Proximity Protein Labeling In Dictyostelium With Engineered Ascorbic Acid Peroxidase 2. J Biol Methods 2023; 10:e99010002. [PMID: 37007980 PMCID: PMC10062472 DOI: 10.14440/jbm.2023.396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2022] [Revised: 02/09/2023] [Accepted: 02/09/2023] [Indexed: 03/18/2023] Open
Abstract
To fully understand any cellular process, we not only need to identify the proteins implicated, but also how the protein network is structurally and spatially organized and changes over time. However, the dynamic nature of many protein interactions involved in cellular signaling pathways continues to be the bottleneck in mapping and studying protein networks. Fortunately, a recently developed proximity labeling method using engineered ascorbic acid peroxidase 2 (APEX2) in mammalian cells allows the identification of weak and/or transient protein interactions with spatial and temporal resolution. Here, we describe a protocol for successfully using the APEX2-proximity labeling method in Dictyostelium, using the cAMP receptor cAR1 as example. Coupled to the identification of the labeled proteins by mass spectrometry, this method expands Dictyostelium's proteomics toolbox and should be widely useful for identifying interacting partners involved in a variety of biological processes in Dictyostelium.
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Affiliation(s)
- Jamie A. Takashima
- Department of Chemistry and Biochemistry, University of Arizona, Tucson AZ, USA
- Current address: Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena CA, USA
| | | | - Pascale G. Charest
- Department of Chemistry and Biochemistry, University of Arizona, Tucson AZ, USA
- Department of Molecular and Cellular Biology, University of Arizona, Tucson AZ, USA
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17
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Velle KB, Garner RM, Beckford TK, Weeda M, Liu C, Kennard AS, Edwards M, Fritz-Laylin LK. A conserved pressure-driven mechanism for regulating cytosolic osmolarity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.01.529730. [PMID: 36909496 PMCID: PMC10002747 DOI: 10.1101/2023.03.01.529730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
Abstract
Controlling intracellular osmolarity is essential to all cellular life. Cells that live in hypo-osmotic environments like freshwater must constantly battle water influx to avoid swelling until they burst. Many eukaryotic cells use contractile vacuoles to collect excess water from the cytosol and pump it out of the cell. Although contractile vacuoles are essential to many species, including important pathogens, the mechanisms that control their dynamics remain unclear. To identify basic principles governing contractile vacuole function, we here investigate the molecular mechanisms of two species with distinct vacuolar morphologies from different eukaryotic lineagesâ€"the discoban Naegleria gruberi , and the amoebozoan slime mold Dictyostelium discoideum . Using quantitative cell biology we find that, although these species respond differently to osmotic challenges, they both use actin for osmoregulation, as well as vacuolar-type proton pumps for filling contractile vacuoles. We also use analytical modeling to show that cytoplasmic pressure is sufficient to drive water out of contractile vacuoles in these species, similar to findings from the alveolate Paramecium multimicronucleatum . Because these three lineages diverged well over a billion years ago, we propose that this represents an ancient eukaryotic mechanism of osmoregulation.
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Affiliation(s)
- Katrina B. Velle
- Department of Biology, University of Massachusetts Amherst, Amherst, MA
| | - Rikki M. Garner
- Department of Systems Biology, Harvard Medical School, Boston, MA
| | | | | | - Chunzi Liu
- Department of Applied Mathematics, Harvard University, Cambridge, MA
| | - Andrew S. Kennard
- Department of Biology, University of Massachusetts Amherst, Amherst, MA
| | - Marc Edwards
- Department of Biology, Amherst College, Amherst, MA
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18
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Rijal R, Ismail I, Jing S, Gomer RH. Starvation induces extracellular accumulation of polyphosphate in Dictyostelium discoideum to inhibit macropinocytosis, phagocytosis, and exocytosis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.16.528874. [PMID: 36824815 PMCID: PMC9949037 DOI: 10.1101/2023.02.16.528874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
Dictyostelium discoideum is a soil-dwelling unicellular eukaryote that accumulates extracellular polyphosphate (polyP). At high cell densities, when the cells are about to overgrow their food supply and starve, the corresponding high extracellular concentrations of polyP allow the cells to preemptively anticipate starvation, inhibit proliferation, and prime themselves to begin development. In this report, we show that starved D. discoideum cells accumulate cell surface and extracellular polyP. Starvation reduces macropinocytosis, exocytosis, and phagocytosis, and we find that these effects require the G protein-coupled polyP receptor (GrlD) and two enzymes, Polyphosphate kinase 1 (Ppk1), which is required for synthesizing intracellular polyP, cell surface polyP, and some of the extracellular polyP, and Inositol hexakisphosphate kinase (I6kA), which is required for cell surface polyP and polyP binding to cells, and some of the extracellular polyP. PolyP reduces membrane fluidity, and we find that starvation reduces membrane fluidity, and this effect requires GrlD and Ppk1 but not I6kA. Together, these data suggest that in starved cells, extracellular polyP decreases membrane fluidity, possibly as a protective measure. In the starved cells, sensing polyP appears to decrease energy expenditure from ingestion, and decrease exocytosis, to both decrease energy expenditures and retain nutrients.
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19
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Structured foraging of soil predators unveils functional responses to bacterial defenses. Proc Natl Acad Sci U S A 2022; 119:e2210995119. [PMID: 36538486 PMCID: PMC9907142 DOI: 10.1073/pnas.2210995119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Predators and their foraging strategies often determine ecosystem structure and function. Yet, the role of protozoan predators in microbial soil ecosystems remains elusive despite the importance of these ecosystems to global biogeochemical cycles. In particular, amoebae-the most abundant soil protozoan predator of bacteria-remineralize soil nutrients and shape the bacterial community. However, their foraging strategies and their role as microbial ecosystem engineers remain unknown. Here, we present a multiscale approach, connecting microscopic single-cell analysis and macroscopic whole ecosystem dynamics, to expose a phylogenetically widespread foraging strategy, in which an amoeba population spontaneously partitions between cells with fast, polarized movement and cells with slow, unpolarized movement. Such differentiated motion gives rise to efficient colony expansion and consumption of the bacterial substrate. From these insights, we construct a theoretical model that predicts how disturbances to amoeba growth rate and movement disrupt their predation efficiency. These disturbances correspond to distinct classes of bacterial defenses, which allows us to experimentally validate our predictions. All considered, our characterization of amoeba foraging identifies amoeba mobility, and not amoeba growth, as the core determinant of predation efficiency and a key target for bacterial defense systems.
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20
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Banerjee T, Biswas D, Pal DS, Miao Y, Iglesias PA, Devreotes PN. Spatiotemporal dynamics of membrane surface charge regulates cell polarity and migration. Nat Cell Biol 2022; 24:1499-1515. [PMID: 36202973 PMCID: PMC10029748 DOI: 10.1038/s41556-022-00997-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Accepted: 08/18/2022] [Indexed: 12/12/2022]
Abstract
During cell migration and polarization, numerous signal transduction and cytoskeletal components self-organize to generate localized protrusions. Although biochemical and genetic analyses have delineated many specific interactions, how the activation and localization of so many different molecules are spatiotemporally orchestrated at the subcellular level has remained unclear. Here we show that the regulation of negative surface charge on the inner leaflet of the plasma membrane plays an integrative role in the molecular interactions. Surface charge, or zeta potential, is transiently lowered at new protrusions and within cortical waves of Ras/PI3K/TORC2/F-actin network activation. Rapid alterations of inner leaflet anionic phospholipids-such as PI(4,5)P2, PI(3,4)P2, phosphatidylserine and phosphatidic acid-collectively contribute to the surface charge changes. Abruptly reducing the surface charge by recruiting positively charged optogenetic actuators was sufficient to trigger the entire biochemical network, initiate de novo protrusions and abrogate pre-existing polarity. These effects were blocked by genetic or pharmacological inhibition of key signalling components such as AKT and PI3K/TORC2. Conversely, increasing the negative surface charge deactivated the network and locally suppressed chemoattractant-induced protrusions or subverted EGF-induced ERK activation. Computational simulations involving excitable biochemical networks demonstrated that slight changes in feedback loops, induced by recruitment of the charged actuators, could lead to outsized effects on system activation. We propose that key signalling network components act on, and are in turn acted upon, by surface charge, closing feedback loops, which bring about the global-scale molecular self-organization required for spontaneous protrusion formation, cell migration and polarity establishment.
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Affiliation(s)
- Tatsat Banerjee
- Department of Cell Biology and Center for Cell Dynamics, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
- Department of Chemical and Biomolecular Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Debojyoti Biswas
- Department of Electrical and Computer Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Dhiman Sankar Pal
- Department of Cell Biology and Center for Cell Dynamics, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Yuchuan Miao
- Department of Cell Biology and Center for Cell Dynamics, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
- Department of Biological Chemistry, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Pablo A Iglesias
- Department of Cell Biology and Center for Cell Dynamics, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
- Department of Electrical and Computer Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Peter N Devreotes
- Department of Cell Biology and Center for Cell Dynamics, School of Medicine, Johns Hopkins University, Baltimore, MD, USA.
- Department of Biological Chemistry, School of Medicine, Johns Hopkins University, Baltimore, MD, USA.
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21
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Wood EC, Glen AK, Kvarfordt LG, Womack F, Acevedo L, Yoon TS, Ma C, Flores V, Sinha M, Chodpathumwan Y, Termehchy A, Roach JC, Mendoza L, Hoffman AS, Deutsch EW, Koslicki D, Ramsey SA. RTX-KG2: a system for building a semantically standardized knowledge graph for translational biomedicine. BMC Bioinformatics 2022; 23:400. [PMID: 36175836 PMCID: PMC9520835 DOI: 10.1186/s12859-022-04932-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 09/14/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Biomedical translational science is increasingly using computational reasoning on repositories of structured knowledge (such as UMLS, SemMedDB, ChEMBL, Reactome, DrugBank, and SMPDB in order to facilitate discovery of new therapeutic targets and modalities. The NCATS Biomedical Data Translator project is working to federate autonomous reasoning agents and knowledge providers within a distributed system for answering translational questions. Within that project and the broader field, there is a need for a framework that can efficiently and reproducibly build an integrated, standards-compliant, and comprehensive biomedical knowledge graph that can be downloaded in standard serialized form or queried via a public application programming interface (API). RESULTS To create a knowledge provider system within the Translator project, we have developed RTX-KG2, an open-source software system for building-and hosting a web API for querying-a biomedical knowledge graph that uses an Extract-Transform-Load approach to integrate 70 knowledge sources (including the aforementioned core six sources) into a knowledge graph with provenance information including (where available) citations. The semantic layer and schema for RTX-KG2 follow the standard Biolink model to maximize interoperability. RTX-KG2 is currently being used by multiple Translator reasoning agents, both in its downloadable form and via its SmartAPI-registered interface. Serializations of RTX-KG2 are available for download in both the pre-canonicalized form and in canonicalized form (in which synonyms are merged). The current canonicalized version (KG2.7.3) of RTX-KG2 contains 6.4M nodes and 39.3M edges with a hierarchy of 77 relationship types from Biolink. CONCLUSION RTX-KG2 is the first knowledge graph that integrates UMLS, SemMedDB, ChEMBL, DrugBank, Reactome, SMPDB, and 64 additional knowledge sources within a knowledge graph that conforms to the Biolink standard for its semantic layer and schema. RTX-KG2 is publicly available for querying via its API at arax.rtx.ai/api/rtxkg2/v1.2/openapi.json . The code to build RTX-KG2 is publicly available at github:RTXteam/RTX-KG2 .
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Affiliation(s)
- E C Wood
- School of Electrical Engineering and Computer Science, Oregon State University, Corvallis, OR, USA
| | - Amy K Glen
- School of Electrical Engineering and Computer Science, Oregon State University, Corvallis, OR, USA.
| | - Lindsey G Kvarfordt
- School of Electrical Engineering and Computer Science, Oregon State University, Corvallis, OR, USA
| | - Finn Womack
- Computer Science and Engineering, Penn State University, State College, PA, USA
| | - Liliana Acevedo
- School of Electrical Engineering and Computer Science, Oregon State University, Corvallis, OR, USA
| | - Timothy S Yoon
- School of Electrical Engineering and Computer Science, Oregon State University, Corvallis, OR, USA
| | - Chunyu Ma
- Huck Institutes of the Life Sciences, Penn State University, State College, PA, USA
| | - Veronica Flores
- School of Electrical Engineering and Computer Science, Oregon State University, Corvallis, OR, USA
| | - Meghamala Sinha
- School of Electrical Engineering and Computer Science, Oregon State University, Corvallis, OR, USA
| | | | - Arash Termehchy
- School of Electrical Engineering and Computer Science, Oregon State University, Corvallis, OR, USA
| | | | | | - Andrew S Hoffman
- Interdisciplinary Hub for Digitalization and Society, Radboud University, Nijmegen, The Netherlands
| | | | - David Koslicki
- Computer Science and Engineering, Penn State University, State College, PA, USA.,Huck Institutes of the Life Sciences, Penn State University, State College, PA, USA.,Department of Biology, Penn State University, State College, PA, USA
| | - Stephen A Ramsey
- School of Electrical Engineering and Computer Science, Oregon State University, Corvallis, OR, USA.,Department of Biomedical Sciences, Oregon State University, Corvallis, OR, USA
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22
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Rijal R, Kirolos SA, Rahman RJ, Gomer RH. Dictyostelium discoideum cells retain nutrients when the cells are about to overgrow their food source. J Cell Sci 2022; 135:276454. [PMID: 36017702 PMCID: PMC9592050 DOI: 10.1242/jcs.260107] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 08/18/2022] [Indexed: 11/20/2022] Open
Abstract
Dictyostelium discoideum is a unicellular eukaryote that eats bacteria, and eventually outgrows the bacteria. D. discoideum cells accumulate extracellular polyphosphate (polyP), and the polyP concentration increases as the local cell density increases. At high cell densities, the correspondingly high extracellular polyP concentrations allow cells to sense that they are about to outgrow their food supply and starve, causing the D. discoideum cells to inhibit their proliferation. In this report, we show that high extracellular polyP inhibits exocytosis of undigested or partially digested nutrients. PolyP decreases plasma membrane recycling and apparent cell membrane fluidity, and this requires the G protein-coupled polyP receptor GrlD, the polyphosphate kinase Ppk1 and the inositol hexakisphosphate kinase I6kA. PolyP alters protein contents in detergent-insoluble crude cytoskeletons, but does not significantly affect random cell motility, cell speed or F-actin levels. Together, these data suggest that D. discoideum cells use polyP as a signal to sense their local cell density and reduce cell membrane fluidity and membrane recycling, perhaps as a mechanism to retain ingested food when the cells are about to starve. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Ramesh Rijal
- Department of Biology, Texas A&M University, College Station, TX 77843-3474, USA
| | - Sara A Kirolos
- Department of Biology, Texas A&M University, College Station, TX 77843-3474, USA
| | - Ryan J Rahman
- Department of Biology, Texas A&M University, College Station, TX 77843-3474, USA
| | - Richard H Gomer
- Department of Biology, Texas A&M University, College Station, TX 77843-3474, USA
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23
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Simple to Complex: The Role of Actin and Microtubules in Mitochondrial Dynamics in Amoeba, Yeast, and Mammalian Cells. Int J Mol Sci 2022; 23:ijms23169402. [PMID: 36012665 PMCID: PMC9409391 DOI: 10.3390/ijms23169402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 08/14/2022] [Accepted: 08/16/2022] [Indexed: 11/17/2022] Open
Abstract
Mitochondria are complex organelles that provide energy for the cell in the form of adenosine triphosphate (ATP) and have very specific structures. For most organisms, this is a reticular or tubular mitochondrial network, while others have singular oval-shaped organelles. Nonetheless, maintenance of this structure is dependent on the mitochondrial dynamics, fission, fusion, and motility. Recently, studies have shown that the cytoskeleton has a significant role in the regulation of mitochondrial dynamics. In this review, we focus on microtubules and actin filaments and look at what is currently known about the cytoskeleton’s role in mitochondrial dynamics in complex models like mammals and yeast, as well as what is known in the simple model system, Dictyostelium discoideum. Understanding how the cytoskeleton is involved in mitochondrial dynamics increases our understanding of mitochondrial disease, especially neurodegenerative diseases. Increases in fission, loss of fusion, and fragmented mitochondria are seen in several neurodegenerative diseases such as Parkinson’s, Alzheimer’s, and Huntington’s disease. There is no known cure for these diseases, but new therapeutic strategies using drugs to alter mitochondrial fusion and fission activity are being considered. The future of these therapeutic studies is dependent on an in-depth understanding of the mechanisms of mitochondrial dynamics. Understanding the cytoskeleton’s role in dynamics in multiple model organisms will further our understanding of these mechanisms and could potentially uncover new therapeutic targets for these neurodegenerative diseases.
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24
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Utthiya S, Wonnapinij P, Napaumpaiporn P, Kittiwongwattana C, Sakulkoo J, Suttangkakul A, Vuttipongchaikij S. Gel purification of gDNA for next-generation sequencing applications. Biotechniques 2022; 73:99-103. [PMID: 35950336 DOI: 10.2144/btn-2022-0013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
We demonstrate that gDNA can be conveniently and efficiently isolated and purified using standard agarose gel electrophoresis, band excision and gel purification. This method yields a substantial amount at microgram levels of gDNA per gel cleanup with high purity. An RNase A treatment step can be omitted. The quality of gDNA is suitable for next-generation sequencing, resulting in >10 Mb reads and high-quality read data (Phred score >28 up to 100 of 150 base reads). Furthermore, the gDNA can be kept intact in a gel slice for several days. This method has been tested for dictyostelids, bacteria and plants.
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Affiliation(s)
- Supanut Utthiya
- Department of Genetics, Faculty of Science, Kasetsart University, Bangkok, 10900, Thailand
| | - Passorn Wonnapinij
- Department of Genetics, Faculty of Science, Kasetsart University, Bangkok, 10900, Thailand.,Center of Advanced studies for Tropical Natural Resources, Kasetsart University, Bangkok, 10900, Thailand.,Omics Center for Agriculture, Bioresources, Food & Health, Kasetsart University (OmiKU), Bangkok, 10900, Thailand
| | - Pondpan Napaumpaiporn
- Department of Genetics, Faculty of Science, Kasetsart University, Bangkok, 10900, Thailand
| | - Chokchai Kittiwongwattana
- Department of Biology, Faculty of Science, King Mongkut's Institute of Technology Ladkrabang, Bangkok, 10520, Thailand
| | - Jenjira Sakulkoo
- Department of Genetics, Faculty of Science, Kasetsart University, Bangkok, 10900, Thailand
| | - Anongpat Suttangkakul
- Department of Genetics, Faculty of Science, Kasetsart University, Bangkok, 10900, Thailand.,Center of Advanced studies for Tropical Natural Resources, Kasetsart University, Bangkok, 10900, Thailand.,Omics Center for Agriculture, Bioresources, Food & Health, Kasetsart University (OmiKU), Bangkok, 10900, Thailand
| | - Supachai Vuttipongchaikij
- Department of Genetics, Faculty of Science, Kasetsart University, Bangkok, 10900, Thailand.,Center of Advanced studies for Tropical Natural Resources, Kasetsart University, Bangkok, 10900, Thailand.,Omics Center for Agriculture, Bioresources, Food & Health, Kasetsart University (OmiKU), Bangkok, 10900, Thailand
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25
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Kufs JE, Reimer C, Stallforth P, Hillmann F, Regestein L. The potential of amoeba-based processes for natural product syntheses. Curr Opin Biotechnol 2022; 77:102766. [PMID: 35944344 DOI: 10.1016/j.copbio.2022.102766] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 07/11/2022] [Accepted: 07/12/2022] [Indexed: 11/18/2022]
Abstract
The identification of novel platform organisms for the production and discovery of small molecules is of high interest for the pharmaceutical industry. In particular, the structural complexity of most natural products with therapeutic potential restricts an industrial production since chemical syntheses often require complex multistep routes. The amoeba Dictyostelium discoideum can be easily cultivated in bioreactors due to its planktonic growth behavior and contains numerous polyketide and terpene synthase genes with only a few compounds being already elucidated. Hence, the amoeba both bears a wealth of hidden natural products and allows for the development of new bioprocesses for existing pharmaceuticals. In this mini review, we present D. discoideum as a novel platform for the production of complex secondary metabolites and discuss its suitability for industrial processes. We also provide initial insights into future bioprocesses, both involving bacterial coculture setups and for the production of plant-based pharmaceuticals.
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Affiliation(s)
- Johann E Kufs
- Bio Pilot Plant, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute (Leibniz-HKI), Jena, Germany
| | - Christin Reimer
- Evolution of Microbial Interactions, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute (Leibniz-HKI), Jena, Germany; Faculty of Biological Sciences, Friedrich Schiller University Jena, Jena, Germany
| | - Pierre Stallforth
- Paleobiotechnology, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute (Leibniz-HKI), Jena, Germany; Friedrich Schiller University Jena, Institute for Organic Chemistry and Macromolecular Chemistry, Jena, Germany
| | - Falk Hillmann
- Evolution of Microbial Interactions, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute (Leibniz-HKI), Jena, Germany
| | - Lars Regestein
- Bio Pilot Plant, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute (Leibniz-HKI), Jena, Germany.
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26
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Cells responding to chemoattractant on a structured substrate. Biophys J 2022; 121:2557-2567. [DOI: 10.1016/j.bpj.2022.05.043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 05/16/2022] [Accepted: 05/25/2022] [Indexed: 11/19/2022] Open
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27
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Boak EN, Kirolos S, Pan H, Pierson LS, Pierson EA. The Type VI Secretion Systems in Plant-Beneficial Bacteria Modulate Prokaryotic and Eukaryotic Interactions in the Rhizosphere. Front Microbiol 2022; 13:843092. [PMID: 35464916 PMCID: PMC9022076 DOI: 10.3389/fmicb.2022.843092] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 03/04/2022] [Indexed: 01/15/2023] Open
Abstract
Rhizosphere colonizing plant growth promoting bacteria (PGPB) increase their competitiveness by producing diffusible toxic secondary metabolites, which inhibit competitors and deter predators. Many PGPB also have one or more Type VI Secretion System (T6SS), for the delivery of weapons directly into prokaryotic and eukaryotic cells. Studied predominantly in human and plant pathogens as a virulence mechanism for the delivery of effector proteins, the function of T6SS for PGPB in the rhizosphere niche is poorly understood. We utilized a collection of Pseudomonas chlororaphis 30-84 mutants deficient in one or both of its two T6SS and/or secondary metabolite production to examine the relative importance of each T6SS in rhizosphere competence, bacterial competition, and protection from bacterivores. A mutant deficient in both T6SS was less persistent than wild type in the rhizosphere. Both T6SS contributed to competitiveness against other PGPB or plant pathogenic strains not affected by secondary metabolite production, but only T6SS-2 was effective against strains lacking their own T6SS. Having at least one T6SS was also essential for protection from predation by several eukaryotic bacterivores. In contrast to diffusible weapons that may not be produced at low cell density, T6SS afford rhizobacteria an additional, more immediate line of defense against competitors and predators.
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Affiliation(s)
- Emily N Boak
- Department of Horticultural Sciences, Texas A&M University, College Station, TX, United States
| | - Sara Kirolos
- Department of Biology, Texas A&M University, College Station, TX, United States
| | - Huiqiao Pan
- Department of Horticultural Sciences, Texas A&M University, College Station, TX, United States.,Department of Embryology, Carnegie Institution for Science, Baltimore, MD, United States
| | - Leland S Pierson
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX, United States
| | - Elizabeth A Pierson
- Department of Horticultural Sciences, Texas A&M University, College Station, TX, United States.,Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX, United States
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28
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Al Jewari C, Baldauf SL. Conflict over the eukaryote root resides in strong outliers, mosaics and missing data sensitivity of site-specific (CAT) mixture models. Syst Biol 2022; 72:1-16. [PMID: 35412616 DOI: 10.1093/sysbio/syac029] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 04/07/2022] [Indexed: 11/14/2022] Open
Abstract
Phylogenetic reconstruction using concatenated loci ("phylogenomics" or "supermatrix phylogeny") is a powerful tool for solving evolutionary splits that are poorly resolved in single gene/protein trees (SGTs). However, recent phylogenomic attempts to resolve the eukaryote root have yielded conflicting results, along with claims of various artefacts hidden in the data. We have investigated these conflicts using two new methods for assessing phylogenetic conflict. ConJak uses whole marker (gene or protein) jackknifing to assess deviation from a central mean for each individual sequence, while ConWin uses a sliding window to screen for incongruent protein fragments (mosaics). Both methods allow selective masking of individual sequences or sequence fragments in order to minimize missing data, an important consideration for resolving deep splits with limited data. Analyses focused on a set of 76 eukaryotic proteins of bacterial-ancestry previously used in various combinations to assess the branching order among the three major divisions of eukaryotes: Amorphea (mainly animals, fungi and Amoebozoa), Diaphoretickes (most other well-known eukaryotes and nearly all algae) and Excavata, represented here by Discoba (Jakobida, Heterolobosea, and Euglenozoa). ConJak analyses found strong outliers to be concentrated in under-sampled lineages, while ConWin analyses of Discoba, the most under-sampled of the major lineages, detected potentially incongruent fragments scattered throughout. Phylogenetic analyses of the full data using an LG-gamma model support a Discoba sister scenario (neozoan-excavate root), which rises to 99-100% bootstrap support with data masked according to either protocol. However, analyses with two site-specific (CAT) mixture models yielded widely inconsistent results and a striking sensitivity to missing data. The neozoan-excavate root places Amorphea and Diaphoretickes as more closely related to each other than either is to Discoba, a fundamental relationship that should remain unaffected by additional taxa.
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Affiliation(s)
- Caesar Al Jewari
- Program in Systematic Biology, Department of Organismal Biology, Uppsala University, Uppsala, Sweden 75236
| | - Sandra L Baldauf
- Program in Systematic Biology, Department of Organismal Biology, Uppsala University, Uppsala, Sweden 75236
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29
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Reimer C, Kufs JE, Rautschek J, Regestein L, Valiante V, Hillmann F. Engineering the amoeba Dictyostelium discoideum for biosynthesis of a cannabinoid precursor and other polyketides. Nat Biotechnol 2022; 40:751-758. [PMID: 34992245 DOI: 10.1038/s41587-021-01143-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Accepted: 10/29/2021] [Indexed: 02/07/2023]
Abstract
Aromatic polyketides are natural polyphenolic compounds with a broad spectrum of pharmacological activities. Production of those metabolites in the model organisms Escherichia coli and Saccharomyces cerevisiae has been limited by the extensive cellular engineering needed for the coordinated biosynthesis of polyketides and their precursors. In contrast, the amoeba Dictyostelium discoideum is a native producer of secondary metabolites and harbors a wide, but largely unexplored, repertoire of genes for the biosynthesis of polyketides and terpenoids. Here we present D. discoideum as an advantageous chassis for the production of aromatic polyketides. By expressing its native and cognate plant polyketide synthase genes in D. discoideum, we demonstrate production of phlorocaprophenone, methyl-olivetol, resveratrol and olivetolic acid (OA), which is the central intermediate in the biosynthesis of cannabinoids. To facilitate OA synthesis, we further engineered an amoeba/plant inter-kingdom hybrid enzyme that produced OA from primary metabolites in two enzymatic steps, providing a shortcut in a synthetic cannabinoid pathway using the D. discoideum host system.
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Affiliation(s)
- Christin Reimer
- Evolution of Microbial Interactions, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute (Leibniz-HKI), Jena, Germany.,Faculty of Biological Sciences, Friedrich Schiller University Jena, Jena, Germany
| | - Johann E Kufs
- Faculty of Biological Sciences, Friedrich Schiller University Jena, Jena, Germany.,Biobricks of Microbial Natural Product Syntheses, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute (Leibniz-HKI), Jena, Germany.,Bio Pilot Plant, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute (Leibniz-HKI), Jena, Germany
| | - Julia Rautschek
- Biobricks of Microbial Natural Product Syntheses, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute (Leibniz-HKI), Jena, Germany
| | - Lars Regestein
- Bio Pilot Plant, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute (Leibniz-HKI), Jena, Germany
| | - Vito Valiante
- Biobricks of Microbial Natural Product Syntheses, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute (Leibniz-HKI), Jena, Germany.
| | - Falk Hillmann
- Evolution of Microbial Interactions, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute (Leibniz-HKI), Jena, Germany.
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30
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Forbes G, Schilde C, Lawal H, Kin K, Du Q, Chen ZH, Rivero F, Schaap P. Interactome and evolutionary conservation of Dictyostelid small GTPases and their direct regulators. Small GTPases 2022; 13:239-254. [PMID: 34565293 PMCID: PMC8923023 DOI: 10.1080/21541248.2021.1984829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
GTP binding proteins known as small GTPases make up one of the largest groups of regulatory proteins and control almost all functions of living cells. Their activity is under, respectively, positive and negative regulation by guanine nucleotide exchange factors (GEFs) and GTPase activating proteins (GAPs), which together with their upstream regulators and the downstream targets of the small GTPases form formidable signalling networks. While genomics has revealed the large size of the GTPase, GEF and GAP repertoires, only a small fraction of their interactions and functions have yet been experimentally explored. Dictyostelid social amoebas have been particularly useful in unravelling the roles of many proteins in the Rac-Rho and Ras-Rap families of GTPases in directional cell migration and regulation of the actin cytoskeleton. Genomes and cell-type specific and developmental transcriptomes are available for Dictyostelium species that span the 0.5 billion years of evolution of the group from their unicellular ancestors. In this work, we identified all GTPases, GEFs and GAPs from genomes representative of the four major taxon groups and investigated their phylogenetic relationships and evolutionary conservation and changes in their functional domain architecture and in their developmental and cell-type specific expression. We performed a hierarchical cluster analysis of the expression profiles of the ~2000 analysed genes to identify putative interacting sets of GTPases, GEFs and GAPs, which highlight sets known to interact experimentally and many novel combinations. This work represents a valuable resource for research into all fields of cellular regulation.
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Affiliation(s)
- Gillian Forbes
- School of Life Sciences, University of Dundee, Dundee, UK
| | | | - Hajara Lawal
- School of Life Sciences, University of Dundee, Dundee, UK
| | - Koryu Kin
- School of Life Sciences, University of Dundee, Dundee, UK,CSIC-Universitat Pompeu Fabra, Institut de Biologia Evolutiva (Csic-universitat Pompeu Fabra), Barcelona, Spain
| | - Qingyou Du
- School of Life Sciences, University of Dundee, Dundee, UK
| | - Zhi-hui Chen
- School of Life Sciences, University of Dundee, Dundee, UK
| | - Francisco Rivero
- Centre for Atherothrombosis and Metabolic Disease, Hull York Medical School, Faculty of Health Sciences, University of Hull, Hull, UK
| | - Pauline Schaap
- School of Life Sciences, University of Dundee, Dundee, UK,CONTACT Pauline Schaap ; School of Life Sciences, University of Dundee, Msi/wtb Complex, Dundee, DD15EH, UK
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31
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Segota I, Edwards MM, Campello A, Rappazzo BH, Wang X, Strandburg-Peshkin A, Zhou XQ, Rachakonda A, Daie K, Lussenhop A, Lee S, Tharratt K, Deshmukh A, Sebesta EM, Zhang M, Lau S, Bennedsen S, Ginsberg J, Campbell T, Wang C, Franck C. Confirmation and variability of the Allee effect in Dictyostelium discoideum cell populations,possible role of chemical signaling within cell clusters. Phys Biol 2021; 19. [PMID: 34942613 DOI: 10.1088/1478-3975/ac4613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Accepted: 12/23/2021] [Indexed: 11/12/2022]
Abstract
In studies of the unicellular eukaryote Dictyostelium discoideum, many have anecdotally observed that cell dilution below a certain "threshold density" causes cells to undergo a period of slow growth (lag). However, little is documented about the slow growth phase and the reason for different growth dynamics below and above this threshold density. In this paper, we extend and correct our earlier work to report an extensive set of experiments, including the use of new cell counting technology, that set this slow-to-fast growth transition on a much firmer biological basis. We show that dilution below a certain density (around 10E4 cells/ml) causes cells to grow slower on average and exhibit a large degree of variability: sometimes a sample does not lag at all, while sometimes it takes many moderate density cell cycle times to recover back to fast growth. We perform conditioned media experiments to demonstrate that a chemical signal mediates this endogenous phenomenon. Finally, we argue that while simple models involving fluid transport of signal molecules or cluster-based signaling explain typical behavior, they do not capture the high degree of variability between samples but nevertheless favor an intra-cluster mechanism.
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Affiliation(s)
- Igor Segota
- Cornell University, Physics Dept., Ithaca, New York, 14853-0001, UNITED STATES
| | - Matthew M Edwards
- Cornell University, Physics Dept., Ithaca, New York, 14853-0001, UNITED STATES
| | - Arthur Campello
- Cornell University, Physics Dept., Ithaca, New York, 14853-0001, UNITED STATES
| | - Brendan H Rappazzo
- Cornell University, Physics Dept., Ithaca, New York, 14853-0001, UNITED STATES
| | - Xiaoning Wang
- Cornell University, Physics Dept., Ithaca, New York, 14853-0001, UNITED STATES
| | | | - Xiao-Qiao Zhou
- Cornell University, Physics Dept., Ithaca, New York, 14853-0001, UNITED STATES
| | - Archana Rachakonda
- Cornell University, Physics Dept., Ithaca, New York, 14853-0001, UNITED STATES
| | - Kayvon Daie
- Cornell University, Physics Dept., Ithaca, New York, 14853-0001, UNITED STATES
| | - Alexander Lussenhop
- Cornell University, Physics Dept., Ithaca, New York, 14853-0001, UNITED STATES
| | - Sungsu Lee
- Cornell University, Physics Dept., Ithaca, New York, 14853-0001, UNITED STATES
| | - Kevin Tharratt
- Cornell University, Physics Dept., Ithaca, New York, 14853-0001, UNITED STATES
| | - Amrish Deshmukh
- Cornell University, Physics Dept., Ithaca, New York, 14853-0001, UNITED STATES
| | - Elisabeth M Sebesta
- Cornell University, Physics Dept., Ithaca, New York, 14853-0001, UNITED STATES
| | - Myron Zhang
- Cornell University, Physics Dept., Ithaca, New York, 14853-0001, UNITED STATES
| | - Sharon Lau
- Cornell University, Physics Dept., Ithaca, New York, 14853-0001, UNITED STATES
| | - Sarah Bennedsen
- Cornell University, Physics Dept., Ithaca, New York, 14853-0001, UNITED STATES
| | - Jared Ginsberg
- Cornell University, Physics Dept., Ithaca, New York, 14853-0001, UNITED STATES
| | - Timothy Campbell
- Cornell University, Physics Dept., Ithaca, New York, 14853-0001, UNITED STATES
| | - Chenzheng Wang
- Cornell University, Physics Dept., Ithaca, New York, 14853-0001, UNITED STATES
| | - Carl Franck
- Physics, Cornell University, Clark Hall, Ithaca, New York, 14853-0001, UNITED STATES
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32
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Extracellular Signalling Modulates Scar/WAVE Complex Activity through Abi Phosphorylation. Cells 2021; 10:cells10123485. [PMID: 34943993 PMCID: PMC8700165 DOI: 10.3390/cells10123485] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 12/01/2021] [Accepted: 12/05/2021] [Indexed: 01/01/2023] Open
Abstract
The lamellipodia and pseudopodia of migrating cells are produced and maintained by the Scar/WAVE complex. Thus, actin-based cell migration is largely controlled through regulation of Scar/WAVE. Here, we report that the Abi subunit-but not Scar-is phosphorylated in response to extracellular signalling in Dictyostelium cells. Like Scar, Abi is phosphorylated after the complex has been activated, implying that Abi phosphorylation modulates pseudopodia, rather than causing new ones to be made. Consistent with this, Scar complex mutants that cannot bind Rac are also not phosphorylated. Several environmental cues also affect Abi phosphorylation-cell-substrate adhesion promotes it and increased extracellular osmolarity diminishes it. Both unphosphorylatable and phosphomimetic Abi efficiently rescue the chemotaxis of Abi KO cells and pseudopodia formation, confirming that Abi phosphorylation is not required for activation or inactivation of the Scar/WAVE complex. However, pseudopodia and Scar patches in the cells with unphosphorylatable Abi protrude for longer, altering pseudopod dynamics and cell speed. Dictyostelium, in which Scar and Abi are both unphosphorylatable, can still form pseudopods, but migrate substantially faster. We conclude that extracellular signals and environmental responses modulate cell migration by tuning the behaviour of the Scar/WAVE complex after it has been activated.
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33
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Bai W, Wells ML, Lai WS, Hicks SN, Burkholder AB, Perera L, Kimmel AR, Blackshear PJ. A post-transcriptional regulon controlled by TtpA, the single tristetraprolin family member expressed in Dictyostelium discoideum. Nucleic Acids Res 2021; 49:11920-11937. [PMID: 34718768 DOI: 10.1093/nar/gkab983] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 10/05/2021] [Accepted: 10/12/2021] [Indexed: 12/30/2022] Open
Abstract
Post-transcriptional processes mediated by mRNA binding proteins represent important control points in gene expression. In eukaryotes, mRNAs containing specific AU-rich motifs are regulated by binding of tristetraprolin (TTP) family tandem zinc finger proteins, which promote mRNA deadenylation and decay, partly through interaction of a conserved C-terminal CNOT1 binding (CNB) domain with CCR4-NOT protein complexes. The social ameba Dictyostelium discoideum shared a common ancestor with humans more than a billion years ago, and expresses only one TTP family protein, TtpA, in contrast to three members expressed in humans. Evaluation of ttpA null-mutants identified six transcripts that were consistently upregulated compared to WT during growth and early development. The 3'-untranslated regions (3'-UTRs) of all six 'TtpA-target' mRNAs contained multiple TTP binding motifs (UUAUUUAUU), and one 3'-UTR conferred TtpA post-transcriptional stability regulation to a heterologous mRNA that was abrogated by mutations in the core TTP-binding motifs. All six target transcripts were upregulated to similar extents in a C-terminal truncation mutant, in contrast to less severe effects of analogous mutants in mice. All six target transcripts encoded probable membrane proteins. In Dictyostelium, TtpA may control an 'RNA regulon', where a single RNA binding protein, TtpA, post-transcriptionally co-regulates expression of several functionally related proteins.
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Affiliation(s)
- Wenli Bai
- Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA
| | - Melissa L Wells
- The Signal Transduction Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
| | - Wi S Lai
- The Signal Transduction Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
| | - Stephanie N Hicks
- The Signal Transduction Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
| | - Adam B Burkholder
- Integrative Bioinformatics Support Group, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
| | - Lalith Perera
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
| | - Alan R Kimmel
- Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA
| | - Perry J Blackshear
- The Signal Transduction Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA.,The Departments of Medicine and Biochemistry, Duke University Medical Center, Durham, NC 27710, USA
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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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Williams RSB, Chubb JR, Insall R, King JS, Pears CJ, Thompson E, Weijer CJ. Moving the Research Forward: The Best of British Biology Using the Tractable Model System Dictyostelium discoideum. Cells 2021; 10:3036. [PMID: 34831258 PMCID: PMC8616412 DOI: 10.3390/cells10113036] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Revised: 11/01/2021] [Accepted: 11/03/2021] [Indexed: 12/19/2022] Open
Abstract
The social amoeba Dictyostelium discoideum provides an excellent model for research across a broad range of disciplines within biology. The organism diverged from the plant, yeast, fungi and animal kingdoms around 1 billion years ago but retains common aspects found in these kingdoms. Dictyostelium has a low level of genetic complexity and provides a range of molecular, cellular, biochemical and developmental biology experimental techniques, enabling multidisciplinary studies to be carried out in a wide range of areas, leading to research breakthroughs. Numerous laboratories within the United Kingdom employ Dictyostelium as their core research model. This review introduces Dictyostelium and then highlights research from several leading British research laboratories, covering their distinct areas of research, the benefits of using the model, and the breakthroughs that have arisen due to the use of Dictyostelium as a tractable model system.
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Affiliation(s)
- Robin S. B. Williams
- Centre for Biomedical Sciences, School of Biological Sciences, Royal Holloway University of London, Egham TW20 0EX, UK
| | - Jonathan R. Chubb
- UCL Laboratory for Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, UK;
| | - Robert Insall
- Institute of Cancer Sciences, University of Glasgow, Switchback Road, Glasgow G61 1QH, UK;
| | - Jason S. King
- School of Biosciences, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK;
| | - Catherine J. Pears
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK;
| | - Elinor Thompson
- School of Science, University of Greenwich, Chatham Maritime, Chatham ME4 4TB, UK;
| | - Cornelis J. Weijer
- Division of Cell and Developmental Biology, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK;
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Ecke M, Prassler J, Gerisch G. Genetic Instability Due to Spindle Anomalies Visualized in Mutants of Dictyostelium. Cells 2021; 10:cells10092240. [PMID: 34571889 PMCID: PMC8469108 DOI: 10.3390/cells10092240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 08/20/2021] [Accepted: 08/24/2021] [Indexed: 11/24/2022] Open
Abstract
Aberrant centrosome activities in mutants of Dictyostelium discoideum result in anomalies of mitotic spindles that affect the reliability of chromosome segregation. Genetic instabilities caused by these deficiencies are tolerated in multinucleate cells, which can be produced by electric-pulse induced cell fusion as a source for aberrations in the mitotic apparatus of the mutant cells. Dual-color fluorescence labeling of the microtubule system and the chromosomes in live cells revealed the variability of spindle arrangements, of centrosome-nuclear interactions, and of chromosome segregation in the atypical mitoses observed.
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Gruenheit N, Baldwin A, Stewart B, Jaques S, Keller T, Parkinson K, Salvidge W, Baines R, Brimson C, Wolf JB, Chisholm R, Harwood AJ, Thompson CRL. Mutant resources for functional genomics in Dictyostelium discoideum using REMI-seq technology. BMC Biol 2021; 19:172. [PMID: 34429112 PMCID: PMC8386026 DOI: 10.1186/s12915-021-01108-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Accepted: 07/22/2021] [Indexed: 01/26/2023] Open
Abstract
Background Genomes can be sequenced with relative ease, but ascribing gene function remains a major challenge. Genetically tractable model systems are crucial to meet this challenge. One powerful model is the social amoeba Dictyostelium discoideum, a eukaryotic microbe widely used to study diverse questions in the cell, developmental and evolutionary biology. Results We describe REMI-seq, an adaptation of Tn-seq, which allows high throughput, en masse, and quantitative identification of the genomic site of insertion of a drug resistance marker after restriction enzyme-mediated integration. We use REMI-seq to develop tools which greatly enhance the efficiency with which the sequence, transcriptome or proteome variation can be linked to phenotype in D. discoideum. These comprise (1) a near genome-wide resource of individual mutants and (2) a defined pool of ‘barcoded’ mutants to allow large-scale parallel phenotypic analyses. These resources are freely available and easily accessible through the REMI-seq website that also provides comprehensive guidance and pipelines for data analysis. We demonstrate that integrating these resources allows novel regulators of cell migration, phagocytosis and macropinocytosis to be rapidly identified. Conclusions We present methods and resources, generated using REMI-seq, for high throughput gene function analysis in a key model system. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-021-01108-y.
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Affiliation(s)
- Nicole Gruenheit
- Centre for Life's Origins and Evolution, Department of Genetics, Evolution and Environment, University College London, Darwin Building, Gower Street, London, WC1E 6BT, UK
| | - Amy Baldwin
- Cardiff School of Biosciences, Cardiff University, Hadyn Ellis Building, Maindy Road, Cardiff, CF24 4HQ, UK
| | - Balint Stewart
- Centre for Life's Origins and Evolution, Department of Genetics, Evolution and Environment, University College London, Darwin Building, Gower Street, London, WC1E 6BT, UK
| | - Sarah Jaques
- Cardiff School of Biosciences, Cardiff University, Hadyn Ellis Building, Maindy Road, Cardiff, CF24 4HQ, UK
| | - Thomas Keller
- Division of Developmental Biology and Medicine, Faculty of Biology, Medicine and Health, The University of Manchester, Michael Smith Building, Oxford Road, Manchester, M13 9PT, UK
| | - Katie Parkinson
- Division of Developmental Biology and Medicine, Faculty of Biology, Medicine and Health, The University of Manchester, Michael Smith Building, Oxford Road, Manchester, M13 9PT, UK
| | - William Salvidge
- Centre for Life's Origins and Evolution, Department of Genetics, Evolution and Environment, University College London, Darwin Building, Gower Street, London, WC1E 6BT, UK
| | - Robert Baines
- Centre for Life's Origins and Evolution, Department of Genetics, Evolution and Environment, University College London, Darwin Building, Gower Street, London, WC1E 6BT, UK
| | - Chris Brimson
- Centre for Life's Origins and Evolution, Department of Genetics, Evolution and Environment, University College London, Darwin Building, Gower Street, London, WC1E 6BT, UK
| | - Jason B Wolf
- Milner Centre for Evolution and Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK
| | - Rex Chisholm
- Feinberg School of Medicine, Northwestern University, Chicago, Illinois, 60611, USA
| | - Adrian J Harwood
- Cardiff School of Biosciences, Cardiff University, Hadyn Ellis Building, Maindy Road, Cardiff, CF24 4HQ, UK.
| | - Christopher R L Thompson
- Centre for Life's Origins and Evolution, Department of Genetics, Evolution and Environment, University College London, Darwin Building, Gower Street, London, WC1E 6BT, UK.
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Xu X, Pan M, Jin T. How Phagocytes Acquired the Capability of Hunting and Removing Pathogens From a Human Body: Lessons Learned From Chemotaxis and Phagocytosis of Dictyostelium discoideum (Review). Front Cell Dev Biol 2021; 9:724940. [PMID: 34490271 PMCID: PMC8417749 DOI: 10.3389/fcell.2021.724940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 07/15/2021] [Indexed: 12/01/2022] Open
Abstract
How phagocytes find invading microorganisms and eliminate pathogenic ones from human bodies is a fundamental question in the study of infectious diseases. About 2.5 billion years ago, eukaryotic unicellular organisms-protozoans-appeared and started to interact with various bacteria. Less than 1 billion years ago, multicellular animals-metazoans-appeared and acquired the ability to distinguish self from non-self and to remove harmful organisms from their bodies. Since then, animals have developed innate immunity in which specialized white-blood cells phagocytes- patrol the body to kill pathogenic bacteria. The social amoebae Dictyostelium discoideum are prototypical phagocytes that chase various bacteria via chemotaxis and consume them as food via phagocytosis. Studies of this genetically amendable organism have revealed evolutionarily conserved mechanisms underlying chemotaxis and phagocytosis and shed light on studies of phagocytes in mammals. In this review, we briefly summarize important studies that contribute to our current understanding of how phagocytes effectively find and kill pathogens via chemotaxis and phagocytosis.
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Affiliation(s)
| | | | - Tian Jin
- Chemotaxis Signal Section, Laboratory of Immunogenetics, NIAID, NIH, Rockville, MD, United States
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Chen S, Annesley SJ, Jasim RAF, Fisher PR. The Parkinson's Disease-Associated Protein DJ-1 Protects Dictyostelium Cells from AMPK-Dependent Outcomes of Oxidative Stress. Cells 2021; 10:cells10081874. [PMID: 34440642 PMCID: PMC8392454 DOI: 10.3390/cells10081874] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 07/17/2021] [Accepted: 07/22/2021] [Indexed: 01/24/2023] Open
Abstract
Mitochondrial dysfunction has been implicated in the pathology of Parkinson’s disease (PD). In Dictyostelium discoideum, strains with mitochondrial dysfunction present consistent, AMPK-dependent phenotypes. This provides an opportunity to investigate if the loss of function of specific PD-associated genes produces cellular pathology by causing mitochondrial dysfunction with AMPK-mediated consequences. DJ-1 is a PD-associated, cytosolic protein with a conserved oxidizable cysteine residue that is important for the protein’s ability to protect cells from the pathological consequences of oxidative stress. Dictyostelium DJ-1 (encoded by the gene deeJ) is located in the cytosol from where it indirectly inhibits mitochondrial respiration and also exerts a positive, nonmitochondrial role in endocytosis (particularly phagocytosis). Its loss in unstressed cells impairs endocytosis and causes correspondingly slower growth, while also stimulating mitochondrial respiration. We report here that oxidative stress in Dictyostelium cells inhibits mitochondrial respiration and impairs phagocytosis in an AMPK-dependent manner. This adds to the separate impairment of phagocytosis caused by DJ-1 knockdown. Oxidative stress also combines with DJ-1 loss in an AMPK-dependent manner to impair or exacerbate defects in phototaxis, morphogenesis and growth. It thereby phenocopies mitochondrial dysfunction. These results support a model in which the oxidized but not the reduced form of DJ-1 inhibits AMPK in the cytosol, thereby protecting cells from the adverse consequences of oxidative stress, mitochondrial dysfunction and the resulting AMPK hyperactivity.
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Affiliation(s)
- Suwei Chen
- Discipline of Microbiology, Department of Physiology Anatomy and Microbiology, School of Life Sciences, La Trobe University, Bundoora, VIC 3086, Australia; (S.C.); (S.J.A.); (R.A.F.J.)
- School of Modern Agriculture and Biotechnology, Ankang University, Ankang 725000, China
| | - Sarah J. Annesley
- Discipline of Microbiology, Department of Physiology Anatomy and Microbiology, School of Life Sciences, La Trobe University, Bundoora, VIC 3086, Australia; (S.C.); (S.J.A.); (R.A.F.J.)
| | - Rasha A. F. Jasim
- Discipline of Microbiology, Department of Physiology Anatomy and Microbiology, School of Life Sciences, La Trobe University, Bundoora, VIC 3086, Australia; (S.C.); (S.J.A.); (R.A.F.J.)
- Department of Laboratory and Clinical Sciences, College of Pharmacy, University of Babylon, Hillah 51002, Iraq
| | - Paul R. Fisher
- Discipline of Microbiology, Department of Physiology Anatomy and Microbiology, School of Life Sciences, La Trobe University, Bundoora, VIC 3086, Australia; (S.C.); (S.J.A.); (R.A.F.J.)
- Correspondence: ; Tel.: +61-3-9479-2229
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40
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McLaren MD, Mathavarajah S, Kim WD, Yap SQ, Huber RJ. Aberrant Autophagy Impacts Growth and Multicellular Development in a Dictyostelium Knockout Model of CLN5 Disease. Front Cell Dev Biol 2021; 9:657406. [PMID: 34291044 PMCID: PMC8287835 DOI: 10.3389/fcell.2021.657406] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 05/28/2021] [Indexed: 12/22/2022] Open
Abstract
Mutations in CLN5 cause a subtype of neuronal ceroid lipofuscinosis (NCL) called CLN5 disease. While the precise role of CLN5 in NCL pathogenesis is not known, recent work revealed that the protein has glycoside hydrolase activity. Previous work on the Dictyostelium discoideum homolog of human CLN5, Cln5, revealed its secretion during the early stages of development and its role in regulating cell adhesion and cAMP-mediated chemotaxis. Here, we used Dictyostelium to examine the effect of cln5-deficiency on various growth and developmental processes during the life cycle. During growth, cln5– cells displayed reduced cell proliferation, cytokinesis, viability, and folic acid-mediated chemotaxis. In addition, the growth of cln5– cells was severely impaired in nutrient-limiting media. Based on these findings, we assessed autophagic flux in growth-phase cells and observed that loss of cln5 increased the number of autophagosomes suggesting that the basal level of autophagy was increased in cln5– cells. Similarly, loss of cln5 increased the amounts of ubiquitin-positive proteins. During the early stages of multicellular development, the aggregation of cln5– cells was delayed and loss of the autophagy genes, atg1 and atg9, reduced the extracellular amount of Cln5. We also observed an increased amount of intracellular Cln5 in cells lacking the Dictyostelium homolog of the human glycoside hydrolase, hexosaminidase A (HEXA), further supporting the glycoside hydrolase activity of Cln5. This observation was also supported by our finding that CLN5 and HEXA expression are highly correlated in human tissues. Following mound formation, cln5– development was precocious and loss of cln5 affected spore morphology, germination, and viability. When cln5– cells were developed in the presence of the autophagy inhibitor ammonium chloride, the formation of multicellular structures was impaired, and the size of cln5– slugs was reduced relative to WT slugs. These results, coupled with the aberrant autophagic flux observed in cln5– cells during growth, support a role for Cln5 in autophagy during the Dictyostelium life cycle. In total, this study highlights the multifaceted role of Cln5 in Dictyostelium and provides insight into the pathological mechanisms that may underlie CLN5 disease.
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Affiliation(s)
- Meagan D McLaren
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, ON, Canada
| | | | - William D Kim
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, ON, Canada
| | - Shyong Q Yap
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, ON, Canada
| | - Robert J Huber
- Department of Biology, Trent University, Peterborough, ON, Canada
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An Autocrine Negative Feedback Loop Inhibits Dictyostelium discoideum Proliferation through Pathways Including IP3/Ca 2. mBio 2021; 12:e0134721. [PMID: 34154396 PMCID: PMC8262924 DOI: 10.1128/mbio.01347-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Little is known about how eukaryotic cells can sense their number or spatial density and stop proliferating when the local density reaches a set value. We previously found that Dictyostelium discoideum accumulates extracellular polyphosphate to inhibit its proliferation, and this requires the G protein-coupled receptor GrlD and the small GTPase RasC. Here, we show that cells lacking the G protein component Gβ, the Ras guanine nucleotide exchange factor GefA, phosphatase and tensin homolog (PTEN), phospholipase C (PLC), inositol 1,4,5-trisphosphate (IP3) receptor-like protein A (IplA), polyphosphate kinase 1 (Ppk1), or the TOR complex 2 component PiaA have significantly reduced sensitivity to polyphosphate-induced proliferation inhibition. Polyphosphate upregulates IP3, and this requires GrlD, GefA, PTEN, PLC, and PiaA. Polyphosphate also upregulates cytosolic Ca2+, and this requires GrlD, Gβ, GefA, RasC, PLC, IplA, Ppk1, and PiaA. Together, these data suggest that polyphosphate uses signal transduction pathways including IP3/Ca2+ to inhibit the proliferation of D. discoideum. IMPORTANCE Many mammalian tissues such as the liver have the remarkable ability to regulate their size and have their cells stop proliferating when the tissue reaches the correct size. One possible mechanism involves the cells secreting a signal that they all sense, and a high level of the signal tells the cells that there are enough of them and to stop proliferating. Although regulating such mechanisms could be useful to regulate tissue size to control cancer or birth defects, little is known about such systems. Here, we use a microbial system to study such a mechanism, and we find that key elements of the mechanism have similarities to human proteins. This then suggests the possibility that we may eventually be able to regulate the proliferation of selected cell types in humans and animals.
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Arthur AL, Crawford A, Houdusse A, Titus MA. VASP-mediated actin dynamics activate and recruit a filopodia myosin. eLife 2021; 10:68082. [PMID: 34042588 PMCID: PMC8352590 DOI: 10.7554/elife.68082] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 05/20/2021] [Indexed: 11/17/2022] Open
Abstract
Filopodia are thin, actin-based structures that cells use to interact with their environments. Filopodia initiation requires a suite of conserved proteins but the mechanism remains poorly understood. The actin polymerase VASP and a MyTH-FERM (MF) myosin, DdMyo7 in amoeba, are essential for filopodia initiation. DdMyo7 is localized to dynamic regions of the actin-rich cortex. Analysis of VASP mutants and treatment of cells with anti-actin drugs shows that myosin recruitment and activation in Dictyostelium requires localized VASP-dependent actin polymerization. Targeting of DdMyo7 to the cortex alone is not sufficient for filopodia initiation; VASP activity is also required. The actin regulator locally produces a cortical actin network that activates myosin and together they shape the actin network to promote extension of parallel bundles of actin during filopodia formation. This work reveals how filopodia initiation requires close collaboration between an actin-binding protein, the state of the actin cytoskeleton and MF myosin activity.
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Affiliation(s)
- Ashley L Arthur
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, United States
| | - Amy Crawford
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, United States
| | - Anne Houdusse
- Structural Motility, Institut Curie, Paris Université Sciences et Lettres, Sorbonne Université, Paris, France
| | - Margaret A Titus
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, United States
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de Oliveira JL, Morales AC, Hurst LD, Urrutia AO, Thompson CRL, Wolf JB. Inferring Adaptive Codon Preference to Understand Sources of Selection Shaping Codon Usage Bias. Mol Biol Evol 2021; 38:3247-3266. [PMID: 33871580 PMCID: PMC8321536 DOI: 10.1093/molbev/msab099] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Alternative synonymous codons are often used at unequal frequencies. Classically, studies of such codon usage bias (CUB) attempted to separate the impact of neutral from selective forces by assuming that deviations from a predicted neutral equilibrium capture selection. However, GC-biased gene conversion (gBGC) can also cause deviation from a neutral null. Alternatively, selection has been inferred from CUB in highly expressed genes, but the accuracy of this approach has not been extensively tested, and gBGC can interfere with such extrapolations (e.g., if expression and gene conversion rates covary). It is therefore critical to examine deviations from a mutational null in a species with no gBGC. To achieve this goal, we implement such an analysis in the highly AT rich genome of Dictyostelium discoideum, where we find no evidence of gBGC. We infer neutral CUB under mutational equilibrium to quantify "adaptive codon preference," a nontautologous genome wide quantitative measure of the relative selection strength driving CUB. We observe signatures of purifying selection consistent with selection favoring adaptive codon preference. Preferred codons are not GC rich, underscoring the independence from gBGC. Expression-associated "preference" largely matches adaptive codon preference but does not wholly capture the influence of selection shaping patterns across all genes, suggesting selective constraints associated specifically with high expression. We observe patterns consistent with effects on mRNA translation and stability shaping adaptive codon preference. Thus, our approach to quantifying adaptive codon preference provides a framework for inferring the sources of selection that shape CUB across different contexts within the genome.
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Affiliation(s)
- Janaina Lima de Oliveira
- Instituto de Biologia, Universidade Federal da Bahia, Salvador, Bahia, 40170-115, Brazil.,Milner Centre for Evolution and Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK
| | - Atahualpa Castillo Morales
- Milner Centre for Evolution and Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK
| | - Laurence D Hurst
- Milner Centre for Evolution and Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK
| | - Araxi O Urrutia
- Milner Centre for Evolution and Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK.,Instituto de Ecologia, UNAM, Ciudad de Mexico 04510, Mexico
| | - Christopher R L Thompson
- Centre for Life's Origins and Evolution, Department of Genetics, Evolution and Environment, University College London, Darwin Building, Gower Street, London, WC1E 6BT, UK
| | - Jason B Wolf
- Milner Centre for Evolution and Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK
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Clapis JR, Fan MJ, Kovarik ML. Supported bilayer membranes for reducing cell adhesion in microfluidic devices. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2021; 13:1535-1540. [PMID: 33690748 DOI: 10.1039/d0ay01992e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The high surface area-to-volume ratio of microfluidic channels makes them susceptible to fouling and clogging when used for biological analyses, including cell-based assays. We evaluated the role of electrostatic and van der Waals interactions in cell adhesion in PDMS microchannels coated with supported lipid bilayers and identified conditions that resulted in minimal cell adhesion. For low ionic strength buffer, optimum results were obtained for a zwitterionic coating of pure egg phosphatidylcholine; for a rich growth medium, the best results were obtained for zwitterionic bilayers or those with slight negative or moderate positive charge from the incorporation of 5-10 mol% egg phosphatidylglycerol or 30 mol% ethylphosphocholine. In both solutions, the presence of 10 g L-1 glucose in the cell suspension reduced cell adhesion. Under optimum conditions, all cells were consistently removed from the channels, demonstrating the utility of these coatings for whole-cell microfluidic assays. These results provide practical information for immediate application and suggest future research areas on cell-lipid interactions.
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Affiliation(s)
- Julia R Clapis
- Department of Chemistry, Trinity College, 300 Summit St., Hartford, CT 06106, USA.
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Martín‐González J, Montero‐Bullón J, Lacal J. Dictyostelium discoideum as a non-mammalian biomedical model. Microb Biotechnol 2021; 14:111-125. [PMID: 33124755 PMCID: PMC7888446 DOI: 10.1111/1751-7915.13692] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 10/06/2020] [Accepted: 10/11/2020] [Indexed: 02/06/2023] Open
Abstract
Dictyostelium discoideum is one of eight non-mammalian model organisms recognized by the National Institute of Health for the study of human pathology. The use of this slime mould is possible owing to similarities in cell structure, behaviour and intracellular signalling with mammalian cells. Its haploid set of chromosomes completely sequenced amenable to genetic manipulation, its unique and short life cycle with unicellular and multicellular stages, and phenotypic richness encoding many human orthologues, make Dictyostelium a representative and simple model organism to unveil cellular processes in human disease. Dictyostelium studies within the biomedical field have provided fundamental knowledge in the areas of bacterial infection, immune cell chemotaxis, autophagy/phagocytosis and mitochondrial and neurological disorders. Consequently, Dictyostelium has been used to the development of related pharmacological treatments. Herein, we review the utilization of Dictyostelium as a model organism in biomedicine.
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Affiliation(s)
- Javier Martín‐González
- Molecular Genetics of Human Diseases GroupDepartment of Microbiology and GeneticsFaculty of BiologyUniversity of SalamancaCampus Miguel de UnamunoSalamancaE‐37007Spain
| | - Javier‐Fernando Montero‐Bullón
- Metabolic Engineering GroupDepartment of Microbiology and GeneticsUniversity of SalamancaCampus Miguel de UnamunoSalamancaE‐37007Spain
| | - Jesus Lacal
- Molecular Genetics of Human Diseases GroupDepartment of Microbiology and GeneticsFaculty of BiologyUniversity of SalamancaCampus Miguel de UnamunoSalamancaE‐37007Spain
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Polyphosphate is an extracellular signal that can facilitate bacterial survival in eukaryotic cells. Proc Natl Acad Sci U S A 2020; 117:31923-31934. [PMID: 33268492 DOI: 10.1073/pnas.2012009117] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Polyphosphate is a linear chain of phosphate residues and is present in organisms ranging from bacteria to humans. Pathogens such as Mycobacterium tuberculosis accumulate polyphosphate, and reduced expression of the polyphosphate kinase that synthesizes polyphosphate decreases their survival. How polyphosphate potentiates pathogenicity is poorly understood. Escherichia coli K-12 do not accumulate detectable levels of extracellular polyphosphate and have poor survival after phagocytosis by Dictyostelium discoideum or human macrophages. In contrast, Mycobacterium smegmatis and Mycobacterium tuberculosis accumulate detectable levels of extracellular polyphosphate, and have relatively better survival after phagocytosis by D. discoideum or macrophages. Adding extracellular polyphosphate increased E. coli survival after phagocytosis by D. discoideum and macrophages. Reducing expression of polyphosphate kinase 1 in M. smegmatis reduced extracellular polyphosphate and reduced survival in D. discoideum and macrophages, and this was reversed by the addition of extracellular polyphosphate. Conversely, treatment of D. discoideum and macrophages with recombinant yeast exopolyphosphatase reduced the survival of phagocytosed M. smegmatis or M. tuberculosis D. discoideum cells lacking the putative polyphosphate receptor GrlD had reduced sensitivity to polyphosphate and, compared to wild-type cells, showed increased killing of phagocytosed E. coli and M. smegmatis Polyphosphate inhibited phagosome acidification and lysosome activity in D. discoideum and macrophages and reduced early endosomal markers in macrophages. Together, these results suggest that bacterial polyphosphate potentiates pathogenicity by acting as an extracellular signal that inhibits phagosome maturation.
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Valenzuela C, Gil M, Urrutia ÍM, Sabag A, Enninga J, Santiviago CA. SopB- and SifA-dependent shaping of the Salmonella-containing vacuole proteome in the social amoeba Dictyostelium discoideum. Cell Microbiol 2020; 23:e13263. [PMID: 32945061 DOI: 10.1111/cmi.13263] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 09/07/2020] [Accepted: 09/09/2020] [Indexed: 02/06/2023]
Abstract
The ability of Salmonella to survive and replicate within mammalian host cells involves the generation of a membranous compartment known as the Salmonella-containing vacuole (SCV). Salmonella employs a number of effector proteins that are injected into host cells for SCV formation using its type-3 secretion systems encoded in SPI-1 and SPI-2 (T3SS-1 and T3SS-2, respectively). Recently, we reported that S. Typhimurium requires T3SS-1 and T3SS-2 to survive in the model amoeba Dictyostelium discoideum. Despite these findings, the involved effector proteins have not been identified yet. Therefore, we evaluated the role of two major S. Typhimurium effectors SopB and SifA during D. discoideum intracellular niche formation. First, we established that S. Typhimurium resides in a vacuolar compartment within D. discoideum. Next, we isolated SCVs from amoebae infected with wild type or the ΔsopB and ΔsifA mutant strains of S. Typhimurium, and we characterised the composition of this compartment by quantitative proteomics. This comparative analysis suggests that S. Typhimurium requires SopB and SifA to modify the SCV proteome in order to generate a suitable intracellular niche in D. discoideum. Accordingly, we observed that SopB and SifA are needed for intracellular survival of S. Typhimurium in this organism. Thus, our results provide insight into the mechanisms employed by Salmonella to survive intracellularly in phagocytic amoebae.
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Affiliation(s)
- Camila Valenzuela
- Laboratorio de Microbiología, Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile.,Dynamics of Host-Pathogen Interactions Unit, Institut Pasteur, Paris, France.,CNRS UMR3691, Paris, France
| | - Magdalena Gil
- Dynamics of Host-Pathogen Interactions Unit, Institut Pasteur, Paris, France.,CNRS UMR3691, Paris, France
| | - Ítalo M Urrutia
- Laboratorio de Microbiología, Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
| | - Andrea Sabag
- Laboratorio de Microbiología, Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
| | - Jost Enninga
- Dynamics of Host-Pathogen Interactions Unit, Institut Pasteur, Paris, France.,CNRS UMR3691, Paris, France
| | - Carlos A Santiviago
- Laboratorio de Microbiología, Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
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Olmos J, Pignataro MF, Benítez dos Santos AB, Bringas M, Klinke S, Kamenetzky L, Velazquez F, Santos J. A Highly Conserved Iron-Sulfur Cluster Assembly Machinery between Humans and Amoeba Dictyostelium discoideum: The Characterization of Frataxin. Int J Mol Sci 2020; 21:E6821. [PMID: 32957566 PMCID: PMC7554988 DOI: 10.3390/ijms21186821] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Revised: 09/05/2020] [Accepted: 09/14/2020] [Indexed: 12/17/2022] Open
Abstract
Several biological activities depend on iron-sulfur clusters ([Fe-S]). Even though they are well-known in several organisms their function and metabolic pathway were poorly understood in the majority of the organisms. We propose to use the amoeba Dictyostelium discoideum, as a biological model to study the biosynthesis of [Fe-S] at the molecular, cellular and organism levels. First, we have explored the D. discoideum genome looking for genes corresponding to the subunits that constitute the molecular machinery for Fe-S cluster assembly and, based on the structure of the mammalian supercomplex and amino acid conservation profiles, we inferred the full functionality of the amoeba machinery. After that, we expressed the recombinant mature form of D. discoideum frataxin protein (DdFXN), the kinetic activator of this pathway. We characterized the protein and its conformational stability. DdFXN is monomeric and compact. The analysis of the secondary structure content, calculated using the far-UV CD spectra, was compatible with the data expected for the FXN fold, and near-UV CD spectra were compatible with the data corresponding to a folded protein. In addition, Tryptophan fluorescence indicated that the emission occurs from an apolar environment. However, the conformation of DdFXN is significantly less stable than that of the human FXN, (4.0 vs. 9.0 kcal mol-1, respectively). Based on a sequence analysis and structural models of DdFXN, we investigated key residues involved in the interaction of DdFXN with the supercomplex and the effect of point mutations on the energetics of the DdFXN tertiary structure. More than 10 residues involved in Friedreich's Ataxia are conserved between the human and DdFXN forms, and a good correlation between mutational effect on the energetics of both proteins were found, suggesting the existence of similar sequence/function/stability relationships. Finally, we integrated this information in an evolutionary context which highlights particular variation patterns between amoeba and humans that may reflect a functional importance of specific protein positions. Moreover, the complete pathway obtained forms a piece of evidence in favor of the hypothesis of a shared and highly conserved [Fe-S] assembly machinery between Human and D. discoideum.
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Affiliation(s)
- Justo Olmos
- Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3), Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Buenos Aires C1428EGA, Argentina; (J.O.); (M.F.P.); (A.B.B.d.S.); (L.K.)
| | - María Florencia Pignataro
- Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3), Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Buenos Aires C1428EGA, Argentina; (J.O.); (M.F.P.); (A.B.B.d.S.); (L.K.)
| | - Ana Belén Benítez dos Santos
- Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3), Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Buenos Aires C1428EGA, Argentina; (J.O.); (M.F.P.); (A.B.B.d.S.); (L.K.)
| | - Mauro Bringas
- Departamento de Química Inorgánica, Analítica y Química Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Instituto de Química Física de los Materiales, Medio Ambiente y Energía (INQUIMAE CONICET), Buenos Aires C1428EGA, Argentina;
| | - Sebastián Klinke
- Fundación Instituto Leloir, IIBBA-CONICET, and Plataforma Argentina de Biología Estructural y Metabolómica PLABEM, Av. Patricias Argentinas 435, Buenos Aires C1405BWE, Argentina;
| | - Laura Kamenetzky
- Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3), Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Buenos Aires C1428EGA, Argentina; (J.O.); (M.F.P.); (A.B.B.d.S.); (L.K.)
- IMPaM, CONICET, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires C1121ABG, Argentina
| | - Francisco Velazquez
- Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3), Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Buenos Aires C1428EGA, Argentina; (J.O.); (M.F.P.); (A.B.B.d.S.); (L.K.)
- Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN)—(UBA/CONICET), Buenos Aires C1428EGA, Argentina
| | - Javier Santos
- Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3), Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Buenos Aires C1428EGA, Argentina; (J.O.); (M.F.P.); (A.B.B.d.S.); (L.K.)
- Consejo Nacional de Investigaciones Científicas y Técnicas, Rivadavia 1917, Buenos Aires C1033AAJ, Argentina
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires. Intendente Güiraldes 2160, Ciudad Universitaria, Buenos Aires C1428EGA, Argentina
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Singh SP, Thomason PA, Lilla S, Schaks M, Tang Q, Goode BL, Machesky LM, Rottner K, Insall RH. Cell-substrate adhesion drives Scar/WAVE activation and phosphorylation by a Ste20-family kinase, which controls pseudopod lifetime. PLoS Biol 2020; 18:e3000774. [PMID: 32745097 PMCID: PMC7425996 DOI: 10.1371/journal.pbio.3000774] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 08/13/2020] [Accepted: 07/13/2020] [Indexed: 01/22/2023] Open
Abstract
The Scar/WAVE complex is the principal catalyst of pseudopod and lamellipod formation. Here we show that Scar/WAVE's proline-rich domain is polyphosphorylated after the complex is activated. Blocking Scar/WAVE activation stops phosphorylation in both Dictyostelium and mammalian cells, implying that phosphorylation modulates pseudopods after they have been formed, rather than controlling whether they are initiated. Unexpectedly, phosphorylation is not promoted by chemotactic signaling but is greatly stimulated by cell:substrate adhesion and diminished when cells deadhere. Phosphorylation-deficient or phosphomimetic Scar/WAVE mutants are both normally functional and rescue the phenotype of knockout cells, demonstrating that phosphorylation is dispensable for activation and actin regulation. However, pseudopods and patches of phosphorylation-deficient Scar/WAVE last substantially longer in mutants, altering the dynamics and size of pseudopods and lamellipods and thus changing migration speed. Scar/WAVE phosphorylation does not require ERK2 in Dictyostelium or mammalian cells. However, the MAPKKK homologue SepA contributes substantially-sepA mutants have less steady-state phosphorylation, which does not increase in response to adhesion. The mutants also behave similarly to cells expressing phosphorylation-deficient Scar, with longer-lived pseudopods and patches of Scar recruitment. We conclude that pseudopod engagement with substratum is more important than extracellular signals at regulating Scar/WAVE's activity and that phosphorylation acts as a pseudopod timer by promoting Scar/WAVE turnover.
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Affiliation(s)
| | | | | | - Matthias Schaks
- Zoological Institute, Technische Universität Braunschweig, Braunschweig, Germany & Cell Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Qing Tang
- Brandeis University, Waltham, Massachusetts, United States of America
| | - Bruce L. Goode
- Brandeis University, Waltham, Massachusetts, United States of America
| | | | - Klemens Rottner
- Zoological Institute, Technische Universität Braunschweig, Braunschweig, Germany & Cell Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Robert H. Insall
- CRUK Beatson Institute, Glasgow, United Kingdom
- Institute of Cancer Sciences, University of Glasgow, Glasgow, United Kingdom
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Bindl J, Molnar ES, Ecke M, Prassler J, Müller-Taubenberger A, Gerisch G. Unilateral Cleavage Furrows in Multinucleate Cells. Cells 2020; 9:E1493. [PMID: 32570994 PMCID: PMC7349700 DOI: 10.3390/cells9061493] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 06/15/2020] [Accepted: 06/16/2020] [Indexed: 12/16/2022] Open
Abstract
Multinucleate cells can be produced in Dictyostelium by electric pulse-induced fusion. In these cells, unilateral cleavage furrows are formed at spaces between areas that are controlled by aster microtubules. A peculiarity of unilateral cleavage furrows is their propensity to join laterally with other furrows into rings to form constrictions. This means cytokinesis is biphasic in multinucleate cells, the final abscission of daughter cells being independent of the initial direction of furrow progression. Myosin-II and the actin filament cross-linking protein cortexillin accumulate in unilateral furrows, as they do in the normal cleavage furrows of mononucleate cells. In a myosin-II-null background, multinucleate or mononucleate cells were produced by cultivation either in suspension or on an adhesive substrate. Myosin-II is not essential for cytokinesis either in mononucleate or in multinucleate cells but stabilizes and confines the position of the cleavage furrows. In fused wild-type cells, unilateral furrows ingress with an average velocity of 1.7 µm × min-1, with no appreciable decrease of velocity in the course of ingression. In multinucleate myosin-II-null cells, some of the furrows stop growing, thus leaving space for the extensive broadening of the few remaining furrows.
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Affiliation(s)
- Julia Bindl
- Max Planck Institute of Biochemistry, Am Klopferspitz 18, D-82152 Martinsried, Germany; (J.B.); (E.S.M.); (M.E.); (J.P.)
| | - Eszter Sarolta Molnar
- Max Planck Institute of Biochemistry, Am Klopferspitz 18, D-82152 Martinsried, Germany; (J.B.); (E.S.M.); (M.E.); (J.P.)
| | - Mary Ecke
- Max Planck Institute of Biochemistry, Am Klopferspitz 18, D-82152 Martinsried, Germany; (J.B.); (E.S.M.); (M.E.); (J.P.)
| | - Jana Prassler
- Max Planck Institute of Biochemistry, Am Klopferspitz 18, D-82152 Martinsried, Germany; (J.B.); (E.S.M.); (M.E.); (J.P.)
| | - Annette Müller-Taubenberger
- LMU Munich, Department of Cell Biology (Anatomy III), Biomedical Center, D-82152 Planegg-Martinsried, Germany;
| | - Günther Gerisch
- Max Planck Institute of Biochemistry, Am Klopferspitz 18, D-82152 Martinsried, Germany; (J.B.); (E.S.M.); (M.E.); (J.P.)
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