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Choong FX, Bäck M, Fahlén S, Johansson LBG, Melican K, Rhen M, Nilsson KPR, Richter-Dahlfors A. Real-time optotracing of curli and cellulose in live Salmonella biofilms using luminescent oligothiophenes. NPJ Biofilms Microbiomes 2016; 2:16024. [PMID: 28721253 PMCID: PMC5515270 DOI: 10.1038/npjbiofilms.2016.24] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 07/15/2016] [Accepted: 09/08/2016] [Indexed: 12/14/2022] Open
Abstract
Extracellular matrix (ECM) is the protein- and polysaccharide-rich backbone of bacterial biofilms that provides a defensive barrier in clinical, environmental and industrial settings. Understanding the dynamics of biofilm formation in native environments has been hindered by a lack of research tools. Here we report a method for simultaneous, real-time, in situ detection and differentiation of the Salmonella ECM components curli and cellulose, using non-toxic, luminescent conjugated oligothiophenes (LCOs). These flexible conjugated polymers emit a conformation-dependent fluorescence spectrum, which we use to kinetically define extracellular appearance of curli fibres and cellulose polysaccharides during bacterial growth. The scope of this technique is demonstrated by defining biofilm morphotypes of Salmonella enterica serovars Enteritidis and Typhimurium, and their isogenic mutants in liquid culture and on solid media, and by visualising the ECM components in native biofilms. Our reported use of LCOs across a number of platforms, including intracellular cellulose production in eukaryotic cells and in infected tissues, demonstrates the versatility of this optotracing technology, and its ability to redefine biofilm research.
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Affiliation(s)
- Ferdinand X Choong
- Swedish Medical Nanoscience Center, Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Marcus Bäck
- Division of Chemistry, Department of Physics, Chemistry and Biology, Linköping University, Linköping, Sweden
| | - Sara Fahlén
- Swedish Medical Nanoscience Center, Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Leif BG Johansson
- Division of Chemistry, Department of Physics, Chemistry and Biology, Linköping University, Linköping, Sweden
| | - Keira Melican
- Swedish Medical Nanoscience Center, Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Mikael Rhen
- Swedish Medical Nanoscience Center, Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
- Department of Microbiology, Tumor and Cell biology, Karolinska Institutet, Stockholm, Sweden
| | - K Peter R Nilsson
- Division of Chemistry, Department of Physics, Chemistry and Biology, Linköping University, Linköping, Sweden
| | - Agneta Richter-Dahlfors
- Swedish Medical Nanoscience Center, Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
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Bahram F, Hydbring P, Tronnersjö S, Zakaria SM, Frings O, Fahlén S, Nilsson H, Goodwin J, von der Lehr N, Su Y, Lüscher B, Castell A, Larsson LG. Interferon-γ-induced p27KIP1 binds to and targets MYC for proteasome-mediated degradation. Oncotarget 2016; 7:2837-54. [PMID: 26701207 PMCID: PMC4823075 DOI: 10.18632/oncotarget.6693] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Accepted: 11/21/2015] [Indexed: 11/25/2022] Open
Abstract
The Myc oncoprotein is tightly regulated at multiple levels including ubiquitin-mediated protein turnover. We recently demonstrated that inhibition of Cdk2-mediated phosphorylation of Myc at Ser-62 pharmacologically or through interferon (IFN)-γ-induced expression of p27Kip1 (p27) repressed Myc's activity to suppress cellular senescence and differentiation. In this study we identified an additional activity of p27 to interfere with Myc independent of Ser-62 phosphorylation. p27 is required and sufficient for IFN-γ-induced turnover of Myc. p27 interacted with Myc in the nucleus involving the C-termini of the two proteins, including Myc box 4 of Myc. The C-terminus but not the Cdk2 binding fragment of p27 was sufficient for inducing Myc degradation. Protein expression data of The Cancer Genome Atlas breast invasive carcinoma set revealed significantly lower Myc protein levels in tumors with highly expressed p27 lacking phosphorylation at Thr-157 - a marker for active p27 localized in the nucleus. Further, these conditions correlated with favorable tumor stage and patient outcome. This novel regulation of Myc by IFN-γ/p27KIP1 potentially offers new possibilities for therapeutic intervention in tumors with deregulated Myc.
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Affiliation(s)
- Fuad Bahram
- Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, Stockholm, Sweden.,Department of Plant Biology and Forest Genetics, Swedish University of Agricultural Sciences, Uppsala, Sweden.,Moreinx AB, Uppsala, Sweden
| | - Per Hydbring
- Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, Stockholm, Sweden.,Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Susanna Tronnersjö
- Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, Stockholm, Sweden.,GE Healthcare, Uppsala, Sweden
| | - Siti Mariam Zakaria
- Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, Stockholm, Sweden
| | - Oliver Frings
- Department of Oncology-Pathology, Science for Life Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Sara Fahlén
- Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, Stockholm, Sweden.,Department of Neuroscience, Swedish Medical Nanoscience Center, Karolinska Institutet, Stockholm, Sweden
| | - Helén Nilsson
- Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, Stockholm, Sweden.,Center for Molecular Pathology, Lund University, Lund, Sweden
| | - Jacob Goodwin
- Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, Stockholm, Sweden
| | - Natalie von der Lehr
- Department of Plant Biology and Forest Genetics, Swedish University of Agricultural Sciences, Uppsala, Sweden.,NatScience, Uppsala, Sweden
| | - Yingtao Su
- Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, Stockholm, Sweden.,Anxun International Co., Limited, Hong Kong, China
| | - Bernhard Lüscher
- Institute of Biochemistry and Molecular Biology, Medical School, RWTH Aachen University, Aachen, Germany
| | - Alina Castell
- Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, Stockholm, Sweden
| | - Lars-Gunnar Larsson
- Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, Stockholm, Sweden
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Stephan O, Cottier S, Fahlén S, Montes-Rodriguez A, Sun J, Eklund DM, Klahre U, Kost B. RISAP is a TGN-associated RAC5 effector regulating membrane traffic during polar cell growth in tobacco. Plant Cell 2014; 26:4426-47. [PMID: 25387880 PMCID: PMC4277221 DOI: 10.1105/tpc.114.131078] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 09/26/2014] [Accepted: 10/15/2014] [Indexed: 05/08/2023]
Abstract
RAC/ROP GTPases coordinate actin dynamics and membrane traffic during polar plant cell expansion. In tobacco (Nicotiana tabacum), pollen tube tip growth is controlled by the RAC/ROP GTPase RAC5, which specifically accumulates at the apical plasma membrane. Here, we describe the functional characterization of RISAP, a RAC5 effector identified by yeast (Saccharomyces cerevisiae) two-hybrid screening. RISAP belongs to a family of putative myosin receptors containing a domain of unknown function 593 (DUF593) and binds via its DUF593 to the globular tail domain of a tobacco pollen tube myosin XI. It also interacts with F-actin and is associated with a subapical trans-Golgi network (TGN) compartment, whose cytoplasmic position at the pollen tube tip is maintained by the actin cytoskeleton. In this TGN compartment, apical secretion and endocytic membrane recycling pathways required for tip growth appear to converge. RISAP overexpression interferes with apical membrane traffic and blocks tip growth. RAC5 constitutively binds to the N terminus of RISAP and interacts in an activation-dependent manner with the C-terminal half of this protein. In pollen tubes, interaction between RAC5 and RISAP is detectable at the subapical TGN compartment. We present a model of RISAP regulation and function that integrates all these findings.
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Affiliation(s)
- Octavian Stephan
- Cell Biology and Erlangen Center of Plant Science (ECROPS), University of Erlangen-Nuremberg, 91058 Erlangen, Germany
| | - Stephanie Cottier
- Centre of Organismal Studies, University of Heidelberg, 69120 Heidelberg, Germany
| | - Sara Fahlén
- Plant Biology and Forest Genetics, Swedish University of Agricultural Sciences, 75007 Uppsala, Sweden
| | - Adriana Montes-Rodriguez
- Cell Biology and Erlangen Center of Plant Science (ECROPS), University of Erlangen-Nuremberg, 91058 Erlangen, Germany
| | - Jia Sun
- Plant Biology and Forest Genetics, Swedish University of Agricultural Sciences, 75007 Uppsala, Sweden
| | - D Magnus Eklund
- Plant Biology and Forest Genetics, Swedish University of Agricultural Sciences, 75007 Uppsala, Sweden
| | - Ulrich Klahre
- Centre of Organismal Studies, University of Heidelberg, 69120 Heidelberg, Germany
| | - Benedikt Kost
- Cell Biology and Erlangen Center of Plant Science (ECROPS), University of Erlangen-Nuremberg, 91058 Erlangen, Germany
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Arabi A, Wu S, Ridderstråle K, Bierhoff H, Shiue C, Fatyol K, Fahlén S, Hydbring P, Söderberg O, Grummt I, Larsson LG, Wright APH. c-Myc associates with ribosomal DNA and activates RNA polymerase I transcription. Nat Cell Biol 2005; 7:303-10. [PMID: 15723053 DOI: 10.1038/ncb1225] [Citation(s) in RCA: 355] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2004] [Accepted: 01/13/2005] [Indexed: 11/08/2022]
Abstract
The c-Myc oncoprotein regulates transcription of genes that are associated with cell growth, proliferation and apoptosis. c-Myc levels are modulated by ubiquitin/proteasome-mediated degradation. Proteasome inhibition leads to c-Myc accumulation within nucleoli, indicating that c-Myc might have a nucleolar function. Here we show that the proteins c-Myc and Max interact in nucleoli and are associated with ribosomal DNA. This association is increased upon activation of quiescent cells and is followed by recruitment of the Myc cofactor TRRAP, enhanced histone acetylation, recruitment of RNA polymerase I (Pol I), and activation of rDNA transcription. Using small interfering RNAs (siRNAs) against c-Myc and an inhibitor of Myc-Max interactions, we demonstrate that c-Myc is required for activating rDNA transcription in response to mitogenic signals. Furthermore, using the ligand-activated MycER (ER, oestrogen receptor) system, we show that c-Myc can activate Pol I transcription in the absence of Pol II transcription. These results suggest that c-Myc coordinates the activity of all three nuclear RNA polymerases, and thereby plays a key role in regulating ribosome biogenesis and cell growth.
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