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Kicińska AK, Rękas M. Alternative application of an iTrack microcatheter and canaloplasty: case report and literature review. Expert Opin Drug Deliv 2023; 20:1201-1208. [PMID: 37700455 DOI: 10.1080/17425247.2023.2256657] [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: 06/19/2023] [Accepted: 09/05/2023] [Indexed: 09/14/2023]
Abstract
INTRODUCTION Glaucoma is the leading cause of irreversible blindness worldwide. Schlemm's canal surgery using an iTrack flexible microcatheter has become popular because of its high quality-of-life issues and the growing demand for less invasive but effective procedures. The unique design of the microcatheter makes it a multimodal tool, which can be used not only in the field of antiglaucoma surgery but also as a drug delivery system to treat various conditions. AREAS COVERED This review presents an update on the selected aspects of a drug delivery system using the iTrack microcatheter, including glaucoma gene therapy and posterior-segment diseases, both in animal models and human patients. The authors also report the case of a patient with branch retinal vein occlusion treated with suprachoroidal bevacizumab in the submacular region administered with the iTrack catheter. EXPERT OPINION The findings presented in this study may indicate that the application of a microcatheter in open-angle glaucoma gene therapy is reasonable and can be combined with full or partial surgical canaloplasty procedures. Translation of this potential into a treatment modality would require overcoming multiple barriers.
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Affiliation(s)
- Aleksandra K Kicińska
- Department of Ophthalmology, Military Institute of Medicine - National Research Institute, Warsaw, Poland
| | - Marek Rękas
- Department of Ophthalmology, Military Institute of Medicine - National Research Institute, Warsaw, Poland
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Keller L, Tardy C, Ligat L, Le Pennec S, Bery N, Koraïchi F, Chinestra P, David M, Gence R, Favre G, Cabantous S, Olichon A. Tripartite split-GFP assay to identify selective intracellular nanobody that suppresses GTPase RHOA subfamily downstream signaling. Front Immunol 2022; 13:980539. [PMID: 36059552 PMCID: PMC9433928 DOI: 10.3389/fimmu.2022.980539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 07/29/2022] [Indexed: 11/24/2022] Open
Abstract
Strategies based on intracellular expression of artificial binding domains present several advantages over manipulating nucleic acid expression or the use of small molecule inhibitors. Intracellularly-functional nanobodies can be considered as promising macrodrugs to study key signaling pathways by interfering with protein-protein interactions. With the aim of studying the RAS-related small GTPase RHOA family, we previously isolated, from a synthetic phage display library, nanobodies selective towards the GTP-bound conformation of RHOA subfamily proteins that lack selectivity between the highly conserved RHOA-like and RAC subfamilies of GTPases. To identify RHOA/ROCK pathway inhibitory intracellular nanobodies, we implemented a stringent, subtractive phage display selection towards RHOA-GTP followed by a phenotypic screen based on F-actin fiber loss. Intracellular interaction and intracellular selectivity between RHOA and RAC1 proteins was demonstrated by adapting the sensitive intracellular protein-protein interaction reporter based on the tripartite split-GFP method. This strategy led us to identify a functional intracellular nanobody, hereafter named RH28, that does not cross-react with the close RAC subfamily and blocks/disrupts the RHOA/ROCK signaling pathway in several cell lines without further engineering or functionalization. We confirmed these results by showing, using SPR assays, the high specificity of the RH28 nanobody towards the GTP-bound conformation of RHOA subfamily GTPases. In the metastatic melanoma cell line WM266-4, RH28 expression triggered an elongated cellular phenotype associated with a loss of cellular contraction properties, demonstrating the efficient intracellular blocking of RHOA/B/C proteins downstream interactions without the need of manipulating endogenous gene expression. This work paves the way for future therapeutic strategies based on protein-protein interaction disruption with intracellular antibodies.
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Affiliation(s)
- Laura Keller
- Centre de Recherche en Cancérologie de Toulouse (CRCT), Université de Toulouse, Institut National de la Santé et de la Recherche Médicale (INSERM), Centre National de la Recherche Scientifique (CNRS), Université Toulouse III-Paul Sabatier, Centre de Recherches en Cancérologie de Toulouse (CRCT), Toulouse, France
- Laboratoire de Biologie Médicale Oncologique, IUCT-Oncopôle, Toulouse, France
| | - Claudine Tardy
- Centre de Recherche en Cancérologie de Toulouse (CRCT), Université de Toulouse, Institut National de la Santé et de la Recherche Médicale (INSERM), Centre National de la Recherche Scientifique (CNRS), Université Toulouse III-Paul Sabatier, Centre de Recherches en Cancérologie de Toulouse (CRCT), Toulouse, France
| | - Laetitia Ligat
- Le Pôle Technologique du Centre de Recherches en Cancérologie de Toulouse, Plateau de Protéomique, Toulouse, France
| | - Soazig Le Pennec
- Centre de Recherche en Cancérologie de Toulouse (CRCT), Université de Toulouse, Institut National de la Santé et de la Recherche Médicale (INSERM), Centre National de la Recherche Scientifique (CNRS), Université Toulouse III-Paul Sabatier, Centre de Recherches en Cancérologie de Toulouse (CRCT), Toulouse, France
| | - Nicolas Bery
- Centre de Recherche en Cancérologie de Toulouse (CRCT), Université de Toulouse, Institut National de la Santé et de la Recherche Médicale (INSERM), Centre National de la Recherche Scientifique (CNRS), Université Toulouse III-Paul Sabatier, Centre de Recherches en Cancérologie de Toulouse (CRCT), Toulouse, France
| | - Faten Koraïchi
- Centre de Recherche en Cancérologie de Toulouse (CRCT), Université de Toulouse, Institut National de la Santé et de la Recherche Médicale (INSERM), Centre National de la Recherche Scientifique (CNRS), Université Toulouse III-Paul Sabatier, Centre de Recherches en Cancérologie de Toulouse (CRCT), Toulouse, France
| | - Patrick Chinestra
- Centre de Recherche en Cancérologie de Toulouse (CRCT), Université de Toulouse, Institut National de la Santé et de la Recherche Médicale (INSERM), Centre National de la Recherche Scientifique (CNRS), Université Toulouse III-Paul Sabatier, Centre de Recherches en Cancérologie de Toulouse (CRCT), Toulouse, France
| | - Mélissa David
- Centre de Recherche en Cancérologie de Toulouse (CRCT), Université de Toulouse, Institut National de la Santé et de la Recherche Médicale (INSERM), Centre National de la Recherche Scientifique (CNRS), Université Toulouse III-Paul Sabatier, Centre de Recherches en Cancérologie de Toulouse (CRCT), Toulouse, France
| | - Rémi Gence
- Centre de Recherche en Cancérologie de Toulouse (CRCT), Université de Toulouse, Institut National de la Santé et de la Recherche Médicale (INSERM), Centre National de la Recherche Scientifique (CNRS), Université Toulouse III-Paul Sabatier, Centre de Recherches en Cancérologie de Toulouse (CRCT), Toulouse, France
| | - Gilles Favre
- Centre de Recherche en Cancérologie de Toulouse (CRCT), Université de Toulouse, Institut National de la Santé et de la Recherche Médicale (INSERM), Centre National de la Recherche Scientifique (CNRS), Université Toulouse III-Paul Sabatier, Centre de Recherches en Cancérologie de Toulouse (CRCT), Toulouse, France
- Laboratoire de Biologie Médicale Oncologique, IUCT-Oncopôle, Toulouse, France
| | - Stéphanie Cabantous
- Laboratoire de Biologie Médicale Oncologique, IUCT-Oncopôle, Toulouse, France
- *Correspondence: Stéphanie Cabantous, ; Aurélien Olichon,
| | - Aurélien Olichon
- Centre de Recherche en Cancérologie de Toulouse (CRCT), Université de Toulouse, Institut National de la Santé et de la Recherche Médicale (INSERM), Centre National de la Recherche Scientifique (CNRS), Université Toulouse III-Paul Sabatier, Centre de Recherches en Cancérologie de Toulouse (CRCT), Toulouse, France
- Institut National de la Santé et de la Recherche Médicale (INSERM), Unité Mixte de Recherche (UMR) 1188 Diabète athérothrombose Réunion Océan Indien (DéTROI), Université de La Réunion, Saint Denis de La Réunion, France
- *Correspondence: Stéphanie Cabantous, ; Aurélien Olichon,
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Tan J, Liu G, Zhu X, Wu Z, Wang N, Zhou L, Zhang X, Fan N, Liu X. Lentiviral Vector-Mediated Expression of Exoenzyme C3 Transferase Lowers Intraocular Pressure in Monkeys. Mol Ther 2019; 27:1327-1338. [PMID: 31129118 DOI: 10.1016/j.ymthe.2019.04.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 04/22/2019] [Accepted: 04/26/2019] [Indexed: 12/17/2022] Open
Abstract
Primary open-angle glaucoma (POAG) is considered a lifelong disease characterized by optic nerve deterioration and visual field damage. Although the disease progression can usually be controlled by lowering the intraocular pressure (IOP), therapeutic effects of current approaches do not last long. Gene therapy could be a promising method for persistent treatment of the disease. Our previous study demonstrated that gene transfer of exoenzyme C3 transferase (C3) to the trabecular meshwork (TM) to inhibit Rho GTPase (Rho), the upstream signal molecule of Rho-associated kinase (ROCK), resulted in lowered IOP in normal rodent eyes. In the present study, we show that the lentiviral vector (LV)-mediated C3 expression inactivates RhoA in human TM cells by ADP ribosylation, resulting in disruption of the actin cytoskeleton and altered cell morphology. In addition, intracameral delivery of the C3 vector to monkey eyes leads to persistently lowered IOP without obvious signs of inflammation. This is the first report of using a vector to transduce the TM of an alive non-human primate with a gene that alters cellular machinery and physiology. Our results in non-human primates support that LV-mediated C3 expression in the TM may have therapeutic potential for glaucoma, the leading cause of irreversible blindness in humans.
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Affiliation(s)
- Junkai Tan
- Xiamen Eye Center, Xiamen University, Xiamen, China; Shenzhen Key Laboratory of Ophthalmology, Shenzhen Eye Hospital, School of Optometry, Shenzhen University, Shenzhen, China
| | - Guo Liu
- Shenzhen Key Laboratory of Ophthalmology, Shenzhen Eye Hospital, School of Optometry, Shenzhen University, Shenzhen, China
| | - Xianjun Zhu
- Institute of Laboratory Animal Sciences, Sichuan Academy of Medical Sciences, Provincial People's Hospital, Chengdu, Sichuan, China; Chengdu Institute of Biology, Sichuan Translational Medicine Research Hospital, Chinese Academy of Sciences, Chengdu, Sichuan, China
| | - Zhijian Wu
- Ocular Gene Therapy Core, National Eye Institute, NIH, 6 Center Drive, Room 307, Bethesda, MD 20892, USA
| | - Ningli Wang
- Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Liang Zhou
- Institute of Laboratory Animal Sciences, Sichuan Academy of Medical Sciences, Provincial People's Hospital, Chengdu, Sichuan, China
| | - Xiaoguang Zhang
- Shenzhen Key Laboratory of Ophthalmology, Shenzhen Eye Hospital, School of Optometry, Shenzhen University, Shenzhen, China
| | - Ning Fan
- Shenzhen Key Laboratory of Ophthalmology, Shenzhen Eye Hospital, School of Optometry, Shenzhen University, Shenzhen, China
| | - Xuyang Liu
- Xiamen Eye Center, Xiamen University, Xiamen, China; Shenzhen Key Laboratory of Ophthalmology, Shenzhen Eye Hospital, School of Optometry, Shenzhen University, Shenzhen, China.
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Tan J, Fan N, Wang N, Feng B, Yang M, Liu G, Wang Y, Zhu X, Kaufman PL, Pang IH, Liu X. Effects of Lentivirus-Mediated C3 Expression on Trabecular Meshwork Cells and Intraocular Pressure. Invest Ophthalmol Vis Sci 2019; 59:4937-4944. [PMID: 30326062 PMCID: PMC6187949 DOI: 10.1167/iovs.18-24978] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose We evaluated the effects of lentivirus-mediated exoenzyme C3 transferase (C3) expression on cultured primary human trabecular meshwork (HTM) cells in vitro, and on rat intraocular pressure (IOP). Methods HTM cells were cultured and treated with lentivirus vectors expressing either green fluorescent protein (GFP) only (LV-GFP) or GFP and C3 together (LV-C3-GFP). Changes in cell morphology and actin stress fibers were assessed. The vectors were also injected into the anterior chamber of rats, and GFP expression was visualized by a Micron III Retinal Imaging Microscope in vivo and a fluorescence microscope ex vivo. Changes in rat IOP were monitored by using a rebound tonometer and the eyes were evaluated by slit lamp. Results LV-mediated C3 expression induced morphologic changes in HTM cells. The cells became retracted and rounded. GFP expression in the anterior chamber angle of rats was observed in vivo from 8 days to 48 days after injection of LV-C3-GFP or LV-GFP. IOP was significantly decreased in the LV-C3-GFP group starting 3 days post injection, and lasting for at least 40 days, when compared to either the contralateral control eyes (the LV-GFP group) or the ipsilateral baseline before injection (P < 0.05). No obvious inflammatory signs were observed in either the LV-C3-GFP or LV-GFP groups. Conclusions LV-mediated C3 expression induced changes in morphology of cultured HTM cells. Intracameral injection of LV-C3-GFP lowered rat IOP for at least 40 days. No significant inflammatory reactions were observed in either the LV-C3-GFP or LV-GFP groups. This study supports the possible use of C3 gene therapy for the treatment of glaucoma.
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Affiliation(s)
- Junkai Tan
- Shenzhen Key Laboratory of Ophthalmology, Shenzhen Eye Hospital, School of Optometry, Shenzhen University, Shenzhen, China
| | - Ning Fan
- Shenzhen Key Laboratory of Ophthalmology, Shenzhen Eye Hospital, School of Optometry, Shenzhen University, Shenzhen, China
| | - Ningli Wang
- Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - BingKai Feng
- Shenzhen Key Laboratory of Ophthalmology, Shenzhen Eye Hospital, School of Optometry, Shenzhen University, Shenzhen, China
| | - Ming Yang
- Shenzhen Key Laboratory of Ophthalmology, Shenzhen Eye Hospital, School of Optometry, Shenzhen University, Shenzhen, China
| | - Guo Liu
- Shenzhen Key Laboratory of Ophthalmology, Shenzhen Eye Hospital, School of Optometry, Shenzhen University, Shenzhen, China
| | - Yun Wang
- Shenzhen Key Laboratory of Ophthalmology, Shenzhen Eye Hospital, School of Optometry, Shenzhen University, Shenzhen, China
| | - Xianjun Zhu
- Institute of Laboratory Animal Sciences, Sichuan Academy of Medical Sciences and Sichuan Provincial Hospital, Chengdu, Sichuan, China
| | - Paul L Kaufman
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, Wisconsin, United States
| | - Iok-Hou Pang
- Department of Pharmaceutical Sciences and North Texas Eye Research Institute, University of North Texas Health Sciences Center, Fort Worth, Texas, United States
| | - Xuyang Liu
- Shenzhen Key Laboratory of Ophthalmology, Shenzhen Eye Hospital, School of Optometry, Shenzhen University, Shenzhen, China
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Sebestyen Z, Scheper W, Vyborova A, Gu S, Rychnavska Z, Schiffler M, Cleven A, Chéneau C, van Noorden M, Peigné CM, Olive D, Lebbink RJ, Oostvogels R, Mutis T, Schuurhuis GJ, Adams EJ, Scotet E, Kuball J. RhoB Mediates Phosphoantigen Recognition by Vγ9Vδ2 T Cell Receptor. Cell Rep 2016; 15:1973-85. [PMID: 27210746 DOI: 10.1016/j.celrep.2016.04.081] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 03/09/2016] [Accepted: 04/21/2016] [Indexed: 11/16/2022] Open
Abstract
Human Vγ9Vδ2 T cells respond to tumor cells by sensing elevated levels of phosphorylated intermediates of the dysregulated mevalonate pathway, which is translated into activating signals by the ubiquitously expressed butyrophilin A1 (BTN3A1) through yet unknown mechanisms. Here, we developed an unbiased, genome-wide screening method that identified RhoB as a critical mediator of Vγ9Vδ2 TCR activation in tumor cells. Our results show that Vγ9Vδ2 TCR activation is modulated by the GTPase activity of RhoB and its redistribution to BTN3A1. This is associated with cytoskeletal changes that directly stabilize BTN3A1 in the membrane, and the subsequent dissociation of RhoB from BTN3A1. Furthermore, phosphoantigen accumulation induces a conformational change in BTN3A1, rendering its extracellular domains recognizable by Vγ9Vδ2 TCRs. These complementary events provide further evidence for inside-out signaling as an essential step in the recognition of tumor cells by a Vγ9Vδ2 TCR.
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Affiliation(s)
- Zsolt Sebestyen
- Department of Hematology and Laboratory of Translational Immunology, University Medical Center Utrecht, Utrecht 3508, the Netherlands
| | - Wouter Scheper
- Department of Hematology and Laboratory of Translational Immunology, University Medical Center Utrecht, Utrecht 3508, the Netherlands
| | - Anna Vyborova
- Department of Hematology and Laboratory of Translational Immunology, University Medical Center Utrecht, Utrecht 3508, the Netherlands
| | - Siyi Gu
- Department of Clinical Chemistry and Hematology, University Medical Center, Utrecht 3508 GA, the Netherlands
| | - Zuzana Rychnavska
- Department of Hematology and Laboratory of Translational Immunology, University Medical Center Utrecht, Utrecht 3508, the Netherlands
| | - Marleen Schiffler
- Department of Hematology and Laboratory of Translational Immunology, University Medical Center Utrecht, Utrecht 3508, the Netherlands
| | - Astrid Cleven
- Department of Hematology and Laboratory of Translational Immunology, University Medical Center Utrecht, Utrecht 3508, the Netherlands
| | - Coraline Chéneau
- Department of Hematology and Laboratory of Translational Immunology, University Medical Center Utrecht, Utrecht 3508, the Netherlands
| | - Martje van Noorden
- Department of Hematology and Laboratory of Translational Immunology, University Medical Center Utrecht, Utrecht 3508, the Netherlands
| | - Cassie-Marie Peigné
- INSERM, Unité Mixte de Recherche 892, Centre de Recherche en Cancérologie Nantes Angers, 44000 Nantes, France; University of Nantes, 44000 Nantes, France; Centre National de la Recherche Scientifique (CNRS), Unité Mixte de Recherche 6299, 44000 Nantes, France
| | - Daniel Olive
- INSERM, Centre de Recherche en Cancérologie Marseille, Institut Paoli-Calmettes, 13009 Marseille, France
| | - Robert Jan Lebbink
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht 3584, the Netherlands
| | - Rimke Oostvogels
- Department of Clinical Chemistry and Hematology, University Medical Center, Utrecht 3508 GA, the Netherlands
| | - Tuna Mutis
- Department of Clinical Chemistry and Hematology, University Medical Center, Utrecht 3508 GA, the Netherlands
| | - Gerrit Jan Schuurhuis
- Department of Hematology, VU University Medical Center, Amsterdam 1081, the Netherlands
| | - Erin J Adams
- Department of Biochemistry and Molecular Biology, University of Chicago, 929 East 57(th) Street, Chicago, IL 60615, USA
| | - Emmanuel Scotet
- INSERM, Unité Mixte de Recherche 892, Centre de Recherche en Cancérologie Nantes Angers, 44000 Nantes, France; University of Nantes, 44000 Nantes, France; Centre National de la Recherche Scientifique (CNRS), Unité Mixte de Recherche 6299, 44000 Nantes, France
| | - Jürgen Kuball
- Department of Hematology and Laboratory of Translational Immunology, University Medical Center Utrecht, Utrecht 3508, the Netherlands.
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Slauson SR, Peters DM, Schwinn MK, Kaufman PL, Gabelt BT, Brandt CR. Viral Vector Effects on Exoenzyme C3 Transferase-Mediated Actin Disruption and on Outflow Facility. Invest Ophthalmol Vis Sci 2015; 56:2431-8. [PMID: 25783606 DOI: 10.1167/iovs.14-15909] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Purified Clostridium botulinum exoenzyme C3 transferase (C3) effects on the actin cytoskeleton in human trabecular meshwork cells (HTM) and on the outflow facility response in monkey organ-cultured anterior segments (MOCAS) were determined in the presence or absence of viral vectors. METHODS Human adenovirus type 5 (AdV) and feline immunodeficiency virus (FIV) vectors were produced using kits. Cell soluble purified C3 (C3cs) was purchased commercially. Recombinant C3 (C3rec) cDNA was overexpressed in Escherichia coli and purified. The HTM cells were incubated with up to 10 μg/mL C3cs or with 5 μg of C3rec and/or viral vector (multiplicity of infection [MOI] = 25). Cells then were fixed and stained for actin. Outflow facility in MOCAS was measured at baseline, 4 hours, 24 hours, and 3 to 4 days following bolus injection of AdV (1.6 × 107 transducing units) and/or 2.5 μg C3rec. RESULTS The HTM cells treated for 4 hours with C3cs (all doses) or for 24 hours with C3rec developed a rounded morphology and lost stress fibers. Cells transduced with vectors alone showed no changes at any time point. Cells exposed to C3rec and cotransduced with either viral vector showed significant disruption of the actin cytoskeleton within 4 hours after exposure, which persisted at 24 hours. In MOCAS, the AdV vector alone had no effect on outflow facility, but enhanced the response to C3rec at 4 hours. CONCLUSIONS Coadministration of viral vectors enhances the ability of C3 transferase to disrupt actin stress fiber formation in HTM cells and increase outflow facility in MOCAS. Viral vectors potentially could be used to increase the bioavailability of proteins for cells that are difficult to transfect.
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Affiliation(s)
- Sarah R Slauson
- Department of Ophthalmology and Visual Sciences, University of Wisconsin, Madison, Wisconsin, United States
| | - Donna M Peters
- Department of Ophthalmology and Visual Sciences, University of Wisconsin, Madison, Wisconsin, United States 2Department of Pathology and Laboratory Medicine, University of Wisconsin, Madison, Wisconsin, United States 3McPherson Eye Research Institute, Uni
| | - Marie K Schwinn
- Department of Pathology and Laboratory Medicine, University of Wisconsin, Madison, Wisconsin, United States
| | - Paul L Kaufman
- Department of Ophthalmology and Visual Sciences, University of Wisconsin, Madison, Wisconsin, United States 3McPherson Eye Research Institute, University of Wisconsin, Madison, Wisconsin, United States
| | - B'Ann T Gabelt
- Department of Ophthalmology and Visual Sciences, University of Wisconsin, Madison, Wisconsin, United States
| | - Curtis R Brandt
- Department of Ophthalmology and Visual Sciences, University of Wisconsin, Madison, Wisconsin, United States 3McPherson Eye Research Institute, University of Wisconsin, Madison, Wisconsin, United States
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Rho/MRTF-A-Induced Integrin Expression Regulates Angiogenesis in Differentiated Multipotent Mesenchymal Stem Cells. Stem Cells Int 2015; 2015:534758. [PMID: 25949242 PMCID: PMC4408638 DOI: 10.1155/2015/534758] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Revised: 03/13/2015] [Accepted: 03/18/2015] [Indexed: 12/13/2022] Open
Abstract
Mesenchymal stem cells (MSCs) are known to undergo endothelial differentiation in response to treatment with vascular endothelial growth factor (VEGF), but their angiogenic ability is poorly characterized. In the present study, we aimed to further investigate the role of Rho/MRTF-A in angiogenesis by MSCs and the effect of the Rho/MRTF-A pathway on the expression of integrins α1β1 and α5β1, which are known to mediate physiological and pathological angiogenesis. Our results showed that increased expression of α1, α5, and β1 was observed during angiogenesis of differentiated MSCs, and the Rho/MRTF-A signaling pathway was demonstrated to be involved in regulating the expression of integrins α1, α5, and β1. Luciferase reporter assay and ChIP assay determined that MRTF-A could bind to and transactivate the integrin α1 and α5 promoters. Treatment with the Rho inhibitor C3 transferase, the Rho-associated protein kinase (ROCK) inhibitor Y27632 or with shMRTF-A inhibited both the upregulation of α1, α5, and β1 as well as angiogenesis. Furthermore, in human umbilical vein endothelial cells (HUVECs), MRTF-A deletion led to marked reductions in cell migration and vessel network formation compared with the control. These data demonstrate that Rho/MRTF-A signaling is an important mediator that controls integrin gene expression during MSC-mediated angiogenic processes.
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Kakudo N, Kushida S, Suzuki K, Matsumoto N, Kusumoto K. Effect of C3 transferase on human adipose-derived stem cells. Hum Cell 2011; 24:165-9. [PMID: 21984005 DOI: 10.1007/s13577-011-0033-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Accepted: 08/18/2011] [Indexed: 11/25/2022]
Abstract
Human adipose-derived stem cells (ASCs) are adult pluripotent stem cells, which have the ability to differentiate into fat, cartilage, bone, or nerves that can be applied in tissue engineering. On the other hand, the exoenzyme C3 transferase (C3) is a Rho inhibitor. Once in the cytosol, the cell-penetrating moiety is released, thereby allowing C3 transferase to freely diffuse intracellularly and inactivate RhoA, RhoB, and RhoC, but not related GTPases such as Cdc42 or Rac1. In this study, we investigated ASC cytoskeletal changes induced by the addition of C3 employing immunofluorescence staining, changes in alpha-smooth muscle actin (a-SMA) gene expression employing real-time RT-PCR, and the Rho-inhibitory effect employing the pull-down assay. C3 significantly reduced stress fiber disruption and a-SMA expression 24 h after its addition at a concentration of 1 μg/ml, and it also reduced the Rho activity level. While the correlation of the occurrence can be assumed, it requires further examination to verify it. C3 may be an effective inhibitor of intracellular signal transmission in ASC cytoskeletal control involving Rho.
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Affiliation(s)
- Natsuko Kakudo
- Department of Plastic and Reconstructive Surgery, Kansai Medical University, 10-15 Fumizono, Moriguchi, Osaka 570-8506, Japan.
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MST kinases monitor actin cytoskeletal integrity and signal via c-Jun N-terminal kinase stress-activated kinase to regulate p21Waf1/Cip1 stability. Mol Cell Biol 2009; 29:6380-90. [PMID: 19822666 DOI: 10.1128/mcb.00116-09] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
As well as providing a structural framework, the actin cytoskeleton plays integral roles in cell death, survival, and proliferation. The disruption of the actin cytoskeleton results in the activation of the c-Jun N-terminal kinase (JNK) stress-activated protein kinase (SAPK) pathway; however, the sensor of actin integrity that couples to the JNK pathway has not been characterized in mammalian cells. We now report that the mammalian Ste20-like (MST) kinases mediate the activation of the JNK pathway in response to the disruption of the actin cytoskeleton. One consequence of actin disruption is the JNK-mediated stabilization of p21(Waf1/Cip1) (p21) via the phosphorylation of Thr57. The expression of MST1 or MST2 was sufficient to stabilize p21 in a JNK- and Thr57-dependent manner, while the stabilization of p21 by actin disruption required MST activity. These data indicate that, in addition to being components of the Salvador-Warts-Hippo tumor suppressor network and binding partners of c-Raf and the RASSF1A tumor suppressor, MST kinases serve to monitor cytoskeletal integrity and couple via the JNK SAPK pathway to the regulation of a key cell cycle regulatory protein.
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Abstract
In a chronic disease such as glaucoma, a therapy that provides a long lasting local effect with minimal systemic side effects, while circumventing the issue of patient compliance, is very attractive. The field of gene therapy is growing rapidly and ocular applications are expanding. Our understanding of the molecular pathogenesis of glaucoma is leading to greater specificity in ocular tissue targeting. Improvements in gene delivery techniques, refinement of vector construction methods, and development of better animal models combine to bring this potential therapy closer to reality.
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Lartey J, López Bernal A. RHO protein regulation of contraction in the human uterus. Reproduction 2009; 138:407-24. [DOI: 10.1530/rep-09-0160] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The state of contraction in smooth muscle cells of the human uterus is dependent on the interaction of activated forms of actin and myosin. Ras homology (RHO) proteins are small monomeric GTP-binding proteins that regulate actin polymerisation and myosin phosphorylation in smooth muscle cells. Their action is determined by their level of expression, GTP-bound state, intracellular localisation and phosphorylated status. Agonist activated RHO proteins bind to effector kinases such as RHO kinase (ROCK) and diaphanous proteins (DIAPH) to regulate smooth muscle contraction by two mechanisms: ROCK activates smooth muscle myosin either by direct phosphorylation at Ser19/Thr18 or through inhibition of myosin phosphatase which is a trimeric protein regulated by ROCK and by other protein kinases. Actin-polymerising proteins such as DIAPH homolog 1 increase filamentous actin assembly to enhance acto-myosin cross bridge formation and contraction. This review explores recent advances in RHO protein signalling in human myometrium and proposes areas of further research to investigate the involvement of these proteins in the regulation of uterine contractility in pregnancy and labour.
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12
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Ivanov AI, Samarin SN, Bachar M, Parkos CA, Nusrat A. Protein kinase C activation disrupts epithelial apical junctions via ROCK-II dependent stimulation of actomyosin contractility. BMC Cell Biol 2009; 10:36. [PMID: 19422706 PMCID: PMC2685374 DOI: 10.1186/1471-2121-10-36] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2008] [Accepted: 05/07/2009] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND Disruption of epithelial cell-cell adhesions represents an early and important stage in tumor metastasis. This process can be modeled in vitro by exposing cells to chemical tumor promoters, phorbol esters and octylindolactam-V (OI-V), known to activate protein kinase C (PKC). However, molecular events mediating PKC-dependent disruption of epithelial cell-cell contact remain poorly understood. In the present study we investigate mechanisms by which PKC activation induces disassembly of tight junctions (TJs) and adherens junctions (AJs) in a model pancreatic epithelium. RESULTS Exposure of HPAF-II human pancreatic adenocarcinoma cell monolayers to either OI-V or 12-O-tetradecanoylphorbol-13-acetate caused rapid disruption and internalization of AJs and TJs. Activity of classical PKC isoenzymes was responsible for the loss of cell-cell contacts which was accompanied by cell rounding, phosphorylation and relocalization of the F-actin motor nonmuscle myosin (NM) II. The OI-V-induced disruption of AJs and TJs was prevented by either pharmacological inhibition of NM II with blebbistatin or by siRNA-mediated downregulation of NM IIA. Furthermore, AJ/TJ disassembly was attenuated by inhibition of Rho-associated kinase (ROCK) II, but was insensitive to blockage of MLCK, calmodulin, ERK1/2, caspases and RhoA GTPase. CONCLUSION Our data suggest that stimulation of PKC disrupts epithelial apical junctions via ROCK-II dependent activation of NM II, which increases contractility of perijunctional actin filaments. This mechanism is likely to be important for cancer cell dissociation and tumor metastasis.
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Affiliation(s)
- Andrei I Ivanov
- Department of Medicine, University of Rochester, Rochester, NY 14642, USA.
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13
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Abstract
Rho kinase (ROCK1 and ROCK2) is a serine/threonine kinase that serves as an important downstream effector of Rho GTPase, and plays a critical role in regulating the contractile tone of smooth muscle tissues in a calcium-independent manner. Several lines of experimental evidence indicate that modulating ROCK activity within the aqueous humor outflow pathway using selective inhibitors could achieve very significant benefits for the treatment of increased intraocular pressure in patients with glaucoma. The rationale for such an approach stems from experimental data suggesting that both ROCK and Rho GTPase inhibitors can increase aqueous humor drainage through the trabecular meshwork, leading to a decrease in intraocular pressure. In addition to their ocular hypotensive properties, inhibitors of both ROCK and Rho GTPase have been shown to enhance ocular blood flow, retinal ganglion cell survival and axon regeneration. These properties of the ROCK and Rho GTPase inhibitors indicate that targeting the Rho GTPase/ROCK pathway with selective inhibitors represents a novel therapeutic approach aimed at lowering increased intraocular pressure in glaucoma patients.
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Affiliation(s)
- Vasantha P Rao
- Department of Ophthalmology, Duke University School of Medicine, Durham, North Carolina, USA.
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14
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Coleman ML, Densham RM, Croft DR, Olson MF. Stability of p21Waf1/Cip1 CDK inhibitor protein is responsive to RhoA-mediated regulation of the actin cytoskeleton. Oncogene 2006; 25:2708-16. [PMID: 16407839 DOI: 10.1038/sj.onc.1209322] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The proto-oncogene Ras GTPase stimulates transcription of p21Waf1/Cip1 (p21), which is repressed by the RhoA GTPase. We previously showed that Ras also elevates p21 protein levels by reducing its proteasome-mediated degradation. Therefore, we investigated whether RhoA also influenced p21 protein degradation. Pulse-chase analysis of p21 protein stability revealed that inhibitors of Rho function, which disrupt filamentous actin (F-actin), drastically slowed p21 degradation. Direct F-actin disruption mimicked Rho inhibition to stabilize p21. We found that Rho inhibition, or F-actin disruption, activated the JNK stress-activated protein kinase, and that interfering with JNK signalling, but not p38, abrogated p21 stabilization by Rho inhibition or F-actin-disrupting drugs. In addition, Ras-transformation led to increased constitutive JNK activity that contributed to the elevated p21 protein levels. These data suggest that p21 stability is influenced by a mechanism that monitors F-actin downstream of Rho, and which acts through a pathway involving activation of JNK. These results may have significant implications for therapies that target Rho-signalling pathways to induce p21-mediated cell-cycle arrest.
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Affiliation(s)
- M L Coleman
- The Wellcome Trust Centre for Human Genetics, Oxford, UK
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15
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Gadea G, Boublik Y, Delga S, Roux P. Efficient production of Clostridium botulinum exotoxin C3 in bacteria: a screening method to optimize production yields. Protein Expr Purif 2005; 40:164-8. [PMID: 15721784 DOI: 10.1016/j.pep.2004.12.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2004] [Revised: 12/03/2004] [Indexed: 10/26/2022]
Abstract
Clostridium botulinum exoenzyme C3 is responsible for the inactivation of members of the Rho GTPase family that are implicated in actin-cytoskeleton reorganization. This property has been extensively used in the field to investigate the functionality of the Rho GTPases. However, systematic analysis of Rho GTPase functions requires large amounts of such inhibitors and consequently an optimization of the production yield of these proteins. Bacterial production of soluble proteins often requires a refolding step that noticeably affects the production yields and necessitates additional experiments to verify functional activity. This is particularly true for TAT-C3, the production yields of which are generally low. In this report, we describe a rapid and efficient method for the production of soluble C3 exoenzyme developed by screening a collection of bacterial strains. The recombinant C3 protein was fused to the TAT protein-transduction domain from HIV, to allow protein delivery into cells, and to a hexahistidine tag, that permitted purification by Nickel affinity chromatography. We have demonstrated the production of large amounts of soluble and functional protein using the bacterial strain AD494 (DE3)pLysS. This rapid and efficient method for the production of soluble C3 exoenzyme could also be useful for the production of other proteins with solubility problems.
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Affiliation(s)
- Gilles Gadea
- Centre de Recherche en Biochimie Macromoléculaire, CNRS FRE 2593, IFR 122, 1919 route de Mende, F-34293 Montpellier cedex 5, France
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16
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Kreibich TA, Chalasani SH, Raper JA. The neurotransmitter glutamate reduces axonal responsiveness to multiple repellents through the activation of metabotropic glutamate receptor 1. J Neurosci 2005; 24:7085-95. [PMID: 15306642 PMCID: PMC6729176 DOI: 10.1523/jneurosci.0349-04.2004] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Glutamate is the major excitatory neurotransmitter in the mammalian CNS. Here, we propose a new role for this neurotransmitter in the developing nervous system. We show that glutamate or the metabotropic class I agonist S-3,5-dihydroxyphenyl glycine, acting through the metabotropic glutamate receptor 1 (mGluR1), can reduce the activity of multiple axonal repellents in vitro. This effect is mediated by a pertussis toxin-sensitive activation of protein kinase A and the subsequent inactivation of Rho. This signaling pathway appears to be identical to the one we described previously for stromal derived factor-1-induced reduction of axonal repellent activities. Activation of mGluR1 can also promote increased survival of embryonic retinal ganglion cells in culture. We propose that neurotransmitter-induced modulation of repellent strength provides a novel mechanism by which activity can influence neuronal morphology.
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Affiliation(s)
- Thomas A Kreibich
- Department of Neuroscience, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA
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17
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Ren XD, Wang R, Li Q, Kahek LAF, Kaibuchi K, Clark RAF. Disruption of Rho signal transduction upon cell detachment. J Cell Sci 2004; 117:3511-8. [PMID: 15226371 DOI: 10.1242/jcs.01205] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Serum-soluble factors play a dominant role in the activation of the small GTPase RhoA. Cell adhesion also modulates RhoA activity but the effect is modest in the absence of serum. Here, we show that cell adhesion is required for serum-stimulated Rho signal transduction leading to myosin light chain (MLC) phosphorylation. Characterization of Rho-kinase substrates revealed that diphosphorylation of MLC at Thr-18 and Ser-19 (ppMLC(T18/S19)) and phosphorylation of the myosin-binding subunit (MBS) of myosin phosphatase at Thr-853 (pMBS(T853)) were mostly Rho and Rho-kinase dependent in attached fibroblasts. MLC monophosphorylation at Ser-19 (pMLC(S19)) was partially dependent on Rho kinase, whereas phosphorylation of MBS at Thr-696 (pMBS(T696)) and phosphorylation of CPI-17 at Thr-38 (pCPI-17(T38)) were mostly Rho-kinase independent. Cell detachment caused a significant reduction in pMLC(S19) and a more dramatic decrease of ppMLC(T18/S19) without inhibiting RhoA. pMBS(T853), pMBS(T696) and pCPI-17(T38) were not significantly reduced, suggesting that myosin-phosphatase activity was little changed. Cells expressing active RhoA (RhoA(V14)) or Rho-kinase catalytic domain maintained elevated pMBS(T853) upon detachment but failed to support ppMLC(T18/S19), indicating that the ability of Rho kinase to phosphorylate MLC is impaired. Reattachment to immobilized fibronectin resulted in a gradual recovery of Rho-kinase-induced ppMLC(T18/S19) that is absent from the cells attached to poly-L-lysine. The convergence of signals from soluble factors and cell adhesion might therefore occur at the point of MLC phosphorylation, providing an effective mechanism for dynamic control of contractility during cell migration.
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Affiliation(s)
- Xiang-Dong Ren
- Department of Dermatology, SUNY at Stony Brook, Stony Brook, NY 11794, USA.
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18
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Rocha CL, Coburn J, Rucks EA, Olson JC. Characterization of Pseudomonas aeruginosa exoenzyme S as a bifunctional enzyme in J774A.1 macrophages. Infect Immun 2003; 71:5296-305. [PMID: 12933877 PMCID: PMC187317 DOI: 10.1128/iai.71.9.5296-5305.2003] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pseudomonas aeruginosa exoenzyme S (ExoS) is a type III secretion (TTS) effector, which includes both a GTPase-activating protein (GAP) activity toward the Rho family of low-molecular-weight G (LMWG) proteins and an ADP-ribosyltransferase (ADPRT) activity that targets LMWG proteins in the Ras, Rab, and Rho families. The coordinate function of both activities of ExoS in J774A.1 macrophages was assessed by using P. aeruginosa strains expressing and translocating wild-type ExoS or ExoS defective in GAP and/or ADPRT activity. Distinct and coordinated functions were identified for both domains. The GAP activity was required for the antiphagocytic effect of ExoS and was linked to interference of lamellopodium and membrane ruffle formation. Alternatively, the ADPRT activity of ExoS altered cellular adherence and morphology and was linked to effects on filopodium formation. The cellular mechanism of ExoS GAP activity included an inactivation of Rac1 function, as determined in p21-activated kinase 1-glutathione S-transferase (GST) pull-down assays. The ADPRT activity of ExoS targeted Ras and RalA but not Rab or Rho proteins, and Ral binding protein 1-GST pull-down assays identified an effect of ExoS ADPRT activity on RalA activation. The results from these studies confirm the bifunctional nature of ExoS activity within macrophages when translocated by TTS.
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Affiliation(s)
- Claudia L Rocha
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, South Carolina 29425, USA
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19
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Henriksson ML, Sundin C, Jansson AL, Forsberg A, Palmer RH, Hallberg B. Exoenzyme S shows selective ADP-ribosylation and GTPase-activating protein (GAP) activities towards small GTPases in vivo. Biochem J 2002; 367:617-28. [PMID: 12132999 PMCID: PMC1222916 DOI: 10.1042/bj20020714] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2002] [Revised: 07/06/2002] [Accepted: 07/22/2002] [Indexed: 11/17/2022]
Abstract
Intracellular targeting of the Pseudomonas aeruginosa toxins exoenzyme S (ExoS) and exoenzyme T (ExoT) initially results in disruption of the actin microfilament structure of eukaryotic cells. ExoS and ExoT are bifunctional cytotoxins, with N-terminal GTPase-activating protein (GAP) and C-terminal ADP-ribosyltransferase activities. We show that ExoS can modify multiple GTPases of the Ras superfamily in vivo. In contrast, ExoT shows no ADP-ribosylation activity towards any of the GTPases tested in vivo. We further examined ExoS targets in vivo and observed that ExoS modulates the activity of several of these small GTP-binding proteins, such as Ras, Rap1, Rap2, Ral, Rac1, RhoA and Cdc42. We suggest that ExoS is the major ADP-ribosyltransferase protein modulating small GTPase function encoded by P. aeruginosa. Furthermore, we show that the GAP activity of ExoS abrogates the activation of RhoA, Cdc42 and Rap1.
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Affiliation(s)
- Maria L Henriksson
- Department of Medical Biosciences/Pathology, Umeå University, S-901 87 Umeå, Sweden
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20
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Mechanisms underlying the Hallmark features of the execution-phase of apoptosis. ACTA ACUST UNITED AC 2001. [DOI: 10.1016/s1566-3124(01)05001-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
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21
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Shiraga M, Ritchie A, Aidoudi S, Baron V, Wilcox D, White G, Ybarrondo B, Murphy G, Leavitt A, Shattil S. Primary megakaryocytes reveal a role for transcription factor NF-E2 in integrin alpha IIb beta 3 signaling. J Cell Biol 1999; 147:1419-30. [PMID: 10613901 PMCID: PMC2174239 DOI: 10.1083/jcb.147.7.1419] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/1999] [Accepted: 11/24/1999] [Indexed: 01/10/2023] Open
Abstract
Platelet integrin alphaIIbbeta3 responds to intracellular signals by binding fibrinogen and triggering cytoskeletal reorganization, but the mechanisms of alphaIIbbeta3 signaling remain poorly understood. To better understand this process, we established conditions to study alphaIIbbeta3 signaling in primary murine megakaryocytes. Unlike platelets, these platelet precursors are amenable to genetic manipulation. Cytokine-stimulated bone marrow cultures produced three arbitrary populations of alphaIIbbeta3-expressing cells with increasing size and DNA ploidy: small progenitors, intermediate-size young megakaryocytes, and large mature megakaryocytes. A majority of the large megakaryocytes bound fibrinogen in response to agonists, while almost none of the smaller cells did. Fibrinogen binding to large megakaryocytes was inhibited by Sindbis virus-mediated expression of isolated beta3 integrin cytoplasmic tails. Strikingly, large megakaryocytes from mice deficient in the transcription factor NF-E2 failed to bind fibrinogen in response to agonists, despite normal surface expression of alphaIIbbeta3. Furthermore, while megakaryocytes from wild-type mice spread on immobilized fibrinogen and exhibited filopodia, lamellipodia and Rho-dependent focal adhesions and stress fibers, NF-E2-deficient megakaryocytes adhered poorly. These studies establish that agonist-induced activation of alphaIIbbeta3 is controlled by NF-E2-regulated signaling pathways that mature late in megakaryocyte development and converge at the beta3 cytoplasmic tail. Megakaryocytes provide a physiologically relevant and tractable system for analysis of bidirectional alphaIIbbeta3 signaling.
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Affiliation(s)
- Masamichi Shiraga
- Department of Vascular Biology, The Scripps Research Institute, La Jolla, California 92037
| | - Alec Ritchie
- Department of Vascular Biology, The Scripps Research Institute, La Jolla, California 92037
| | - Sallouha Aidoudi
- Department of Vascular Biology, The Scripps Research Institute, La Jolla, California 92037
| | - Veronique Baron
- Department of Vascular Biology, The Scripps Research Institute, La Jolla, California 92037
| | - David Wilcox
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
| | - Gilbert White
- Department of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | | | - George Murphy
- Department of Laboratory Medicine, The University of California at San Francisco, San Francisco, California 94143
| | - Andrew Leavitt
- Department of Laboratory Medicine, The University of California at San Francisco, San Francisco, California 94143
| | - Sanford Shattil
- Department of Vascular Biology, The Scripps Research Institute, La Jolla, California 92037
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22
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Hahn YS, Guanzon A, Rice CM, Hahn CS. Class I MHC Molecule-Mediated Inhibition of Sindbis Virus Replication. THE JOURNAL OF IMMUNOLOGY 1999. [DOI: 10.4049/jimmunol.162.1.69] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
The threshold for systemic viral infection relies on the amplification of virus at a primary infection site. We have identified that class I MHC molecules can trigger the inhibition of replication of Sindbis virus in a haplotype- and allele-specific manner. Class I MHC molecules of H-2d haplotypes exhibit a strong inhibitory effect whereas H-2k haplotypes show minimal inhibition of Sindbis viral replication. By a single gene transfection of H-2d class I MHC molecules, into cells that express class I MHC molecules of H-2k haplotype and are susceptible to viral replication, these cells became resistant to viral replication. The inhibition of viral replication by class I MHC molecules occurs neither during the stage of virus entry/endocytosis nor during virus maturation. Rather, viral-specific RNA replication, as well as viral gene expression, are inhibited in cells expressing inhibitory class I MHC molecules. This class I MHC molecule-mediated inhibition requires newly synthesized host gene products, implying the activation of an intracellular signaling mechanism that is triggered by specific class I MHC molecules.
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Affiliation(s)
- Young S. Hahn
- *Beirne Carter Center for Immunology Research and Departments of
- †Pathology and
| | - Angelo Guanzon
- *Beirne Carter Center for Immunology Research and Departments of
| | - Charles M. Rice
- §Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110
| | - Chang S. Hahn
- *Beirne Carter Center for Immunology Research and Departments of
- ‡Microbiology, University of Virginia Health Sciences Center, Charlottesville, VA 22908; and
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23
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Barth H, Hofmann F, Olenik C, Just I, Aktories K. The N-terminal part of the enzyme component (C2I) of the binary Clostridium botulinum C2 toxin interacts with the binding component C2II and functions as a carrier system for a Rho ADP-ribosylating C3-like fusion toxin. Infect Immun 1998; 66:1364-9. [PMID: 9529054 PMCID: PMC108061 DOI: 10.1128/iai.66.4.1364-1369.1998] [Citation(s) in RCA: 142] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The binary actin-ADP-ribosylating Clostridium botulinum C2 toxin consists of the enzyme component C2I and the binding component C2II, which are separate proteins. The active component C2I enters cells through C2II by receptor-mediated endocytosis and membrane translocation. The N-terminal part of C2I (C2IN), which consists of 225 amino acid residues but lacks ADP-ribosyltransferase activity, was identified as the C2II contact site. A fusion protein (C2IN-C3) of C2IN and the full-length C3-like ADP-ribosyltransferase from Clostridium limosum was constructed. The fusion protein C2IN-C3 ADP-ribosylated Rho but not actin in CHO cell lysates. Together with C2II, C2IN-C3 induced complete rounding up of CHO and HeLa cells after incubation for 3 h. No cell rounding was observed without C2II or with the original C3-like transferase from C. limosum. The data indicate that the N-terminal 225 amino acid residues of C2I are sufficient to cause the cellular uptake of C. limosum transferase via the binding component of C2II, thereby increasing the cytotoxicity of the C3-like exoenzyme several hundred-fold.
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Affiliation(s)
- H Barth
- Institut für Pharmakologie und Toxikologie der Albert-Ludwigs-Universität Freiburg, Germany
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24
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Mills JC, Stone NL, Erhardt J, Pittman RN. Apoptotic membrane blebbing is regulated by myosin light chain phosphorylation. J Cell Biol 1998; 140:627-36. [PMID: 9456322 PMCID: PMC2140178 DOI: 10.1083/jcb.140.3.627] [Citation(s) in RCA: 377] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/1997] [Revised: 12/10/1997] [Indexed: 02/06/2023] Open
Abstract
The evolutionarily conserved execution phase of apoptosis is defined by characteristic changes occurring during the final stages of death; specifically cell shrinkage, dynamic membrane blebbing, condensation of chromatin, and DNA fragmentation. Mechanisms underlying these hallmark features of apoptosis have previously been elusive, largely because the execution phase is a rapid event whose onset is asynchronous across a population of cells. In the present study, a model system is described for using the caspase inhibitor, z-VAD-FMK, to block apoptosis and generate a synchronous population of cells actively extruding and retracting membrane blebs. This model system allowed us to determine signaling mechanisms underlying this characteristic feature of apoptosis. A screen of kinase inhibitors performed on synchronized blebbing cells indicated that only myosin light chain kinase (MLCK) inhibitors decreased blebbing. Immunoprecipitation of myosin II demonstrated that myosin regulatory light chain (MLC) phosphorylation was increased in blebbing cells and that MLC phosphorylation was prevented by inhibitors of MLCK. MLC phosphorylation is also mediated by the small G protein, Rho. C3 transferase inhibited apoptotic membrane blebbing, supporting a role for a Rho family member in this process. Finally, blebbing was also inhibited by disruption of the actin cytoskeleton. Based on these results, a working model is proposed for how actin/myosin II interactions cause cell contraction and membrane blebbing. Our results provide the first evidence that MLC phosphorylation is critical for apoptotic membrane blebbing and also implicate Rho signaling in these active morphological changes. The model system described here should facilitate future studies of MLCK, Rho, and other signal transduction pathways activated during the execution phase of apoptosis.
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Affiliation(s)
- J C Mills
- Department of Pharmacology, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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25
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6.10 Bacterial Exotoxins. J Microbiol Methods 1998. [DOI: 10.1016/s0580-9517(08)70291-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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26
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Lucius C, Arner A, Steusloff A, Troschka M, Hofmann F, Aktories K, Pfitzer G. Clostridium difficile toxin B inhibits carbachol-induced force and myosin light chain phosphorylation in guinea-pig smooth muscle: role of Rho proteins. J Physiol 1998; 506 ( Pt 1):83-93. [PMID: 9481674 PMCID: PMC2230702 DOI: 10.1111/j.1469-7793.1998.083bx.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
1. Clostridium difficile toxin B glucosylates the Ras-related low molecular mass GTPases of the Rho subfamily thereby inactivating them. In the present report, toxin B was applied as a tool to test whether Rho proteins participate in the carbachol-induced increase in the Ca2+ sensitivity of force and myosin light chain (MLC) phosphorylation in intact intestinal smooth muscle. 2. Small strips of the longitudinal muscle of guinea-pig small intestine were incubated in toxin B (40 ng ml-1) overnight. Carbachol-induced force and intracellular [Ca2+], and, in a separate series, force and MLC phosphorylation, were determined. 3. Carbachol induced a biphasic contraction: an initial rapid increase in force (peak 1) followed by a partial relaxation and a second delayed increase in force (peak 2). The peak of the Ca2+ signal measured with fura-2 preceded peak 1 of force and then declined to a lower suprabasal steady-state level. Peak 2 was not associated with a significant increase in [Ca2+]. Toxin B nearly completely inhibited peak 2 while peak 1 was not significantly inhibited. Toxin B had no effect on the Ca2+ transient. 4. In control strips, MLC phosphorylation at peak 2 was 27.7% which was significantly higher than the resting value (18.6%). The inhibition of the second, delayed, rise in force induced by toxin B was associated with complete inhibition of the increase in MLC phosphorylation. The resting MLC phosphorylation was not significantly different from that of the control strips. 5. The initial increase in MLC phosphorylation determined 3 s after exposure to carbachol was 54% in the control strips. Toxin B also inhibited this initial phosphorylation peak despite the fact that the Ca2+ transient and the initial increase in force were not inhibited by toxin B. This suggests that Rho proteins play an important role in setting the balance between MLC phosphorylation and dephosphorylation reactions even at high levels of intracellular Ca2+. 6. These findings are consistent with the hypothesis that the delayed rise in force elicited by carbachol is due to an increase in the Ca2+ sensitivity of MLC phosphorylation mediated by Rho proteins.
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Affiliation(s)
- C Lucius
- Institut für Physiologie, Charité, Humboldt-Universität zu Berlin, Germany
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27
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9.3 Cytoskeletal Rearrangements Induced by Bacterial Pathogens. METHODS IN MICROBIOLOGY 1998. [DOI: 10.1016/s0580-9517(08)70308-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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28
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Henning SW, Galandrini R, Hall A, Cantrell DA. The GTPase Rho has a critical regulatory role in thymus development. EMBO J 1997; 16:2397-407. [PMID: 9171353 PMCID: PMC1169840 DOI: 10.1093/emboj/16.9.2397] [Citation(s) in RCA: 115] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The present study employs a genetic approach to explore the role of Rho GTPases in murine thymic development. Inactivation of Rho function in the thymus was achieved by thymic targeting of a transgene encoding C3 transferase from Clostridium botulinum which selectively ADP-ribosylates Rho within its effector domain and thereby abolishes its biological function. Thymi lacking functional Rho isolated from C3 transgenic mice were strikingly smaller and showed a marked (90%) decrease in cellularity compared with their normal litter mates. We also observed a similar decrease in levels of peripheral T cells in C3 transgenic mice. Analysis of the maturation status of thymocytes indicated that differentiation of progenitor cells to mature T cells can occur in the absence of Rho function, and both positive and negative selection of T cells appear to be intact. However, transgenic mice that lack Rho function in the thymus show maturational, proliferative and cell survival defects during T-cell development that severely impair the generation of normal numbers of thymocytes and mature peripheral T cells. The present study thus identifies a role for Rho-dependent signalling pathways in thymocyte development. The data show that the function of Rho GTPases is critical for the proliferative expansion of thymocytes. This defines a selective role for the GTPase Rho in early thymic development as a critical integrator of proliferation and cell survival signals.
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Affiliation(s)
- S W Henning
- Lymphocyte Activation Laboratory, Imperial Cancer Research Fund, London, UK.
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Affiliation(s)
- K Aktories
- Institut für Pharmakologie and Toxikologie, Albert-Ludwigs-Universität Freiburg, Germany.
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Aktories K. Identification of the catalytic site of clostridial ADP-ribosyltransferases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1997; 419:53-60. [PMID: 9193636 DOI: 10.1007/978-1-4419-8632-0_6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The catalytic sites of clostridial ADP-ribosyltransferases were studied by photoaffinity-labelling with [carbonyl-14C]NAD+. In C3-like transferases, which are known to modify low molecular mass GTP-binding Rho proteins, Glu-174 was identified to be essential for catalysis. In C. perfringens iota toxin, Glu-380 and Glu-378 may have pivotal roles in the active site of this actin-ADP-ribosylating toxin.
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Affiliation(s)
- K Aktories
- Institut für Pharmakologie und Toxikologie, Albert-Ludwigs-Universität Freiburg, Germany
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Hakomori SI. Functional Roles of Glycosphingolipids and Sphingolipids in Signal Transduction. SPHINGOLIPID-MEDIATED SIGNAL TRANSDUCTION 1997. [DOI: 10.1007/978-3-662-22425-0_10] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Otto B, Steusloff A, Just I, Aktories K, Pfitzer G. Role of Rho proteins in carbachol-induced contractions in intact and permeabilized guinea-pig intestinal smooth muscle. J Physiol 1996; 496 ( Pt 2):317-29. [PMID: 8910218 PMCID: PMC1160879 DOI: 10.1113/jphysiol.1996.sp021687] [Citation(s) in RCA: 95] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
1. The aim of this study was to determine whether the low molecular mass GTPase RhoA or related proteins are involved in carbachol- and high-K(+)-induced contractions in intact intestinal smooth muscle as well as the carbachol-induced increase in Ca2+ sensitivity of the myofilaments in permeabilized preparations. 2. The carbachol-induced increase in the Ca2+ sensitivity of force production in beta-escin-permeabilized intestinal smooth muscle was enhanced in preparations that were loaded with the constitutively active mutant of RhoA, Val14RhoA, and was inhibited by exoenzyme C3 from Clostridium botulinum, which ADP-ribosylates and inactivates small GTPases of the Rho family. The effect of C3 on Ca2+ sensitivity in the absence of the agonist was negligible, while the maximal Ca(2+)-activated force was inhibited by about 20%. 3. Inhibition of carbachol-induced force was associated with an increase in ADP-ribosylation of a protein band with a molecular mass of approximately 22 kDa, corresponding to Rho, and was partially reversed in the presence of Ile41RhoA, which is not a substrate for C3. Val14RhoA did not restore carbachol-induced Ca2+ sensitization in C3-treated smooth muscle. 4. In intact intestinal smooth muscle, toxin B from Clostridium difficile, which monoglucosylates members of the Rho family, inhibited high-K(+)-induced contractions and the initial phasic response to carbachol by about 30%. The delayed contractile response to carbachol was completely inhibited. 5. In smooth muscle preparations that were permeabilized with beta-escin after treatment with toxin B, carbachol-and GTP gamma S-induced Ca2+ sensitization was significantly inhibited. 6. These findings are consistent with a role for Rho or Rho-like proteins in agonist-induced increase in Ca2+ sensitivity of force production in intact and permeabilized intestinal smooth muscle.
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Affiliation(s)
- B Otto
- II. Physiologisches Institut, Universität Heidelberg, Germany
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Rebollo A, Gómez J, Martínez-A C. Lessons from immunological, biochemical, and molecular pathways of the activation mediated by IL-2 and IL-4. Adv Immunol 1996; 63:127-96. [PMID: 8787631 DOI: 10.1016/s0065-2776(08)60856-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- A Rebollo
- Department of Immunology and Oncology, Centro Nacional de Biotecnología, Universidad Autónoma de Madrid, Spain
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Just I, Selzer J, von Eichel-Streiber C, Aktories K. The low molecular mass GTP-binding protein Rho is affected by toxin A from Clostridium difficile. J Clin Invest 1995; 95:1026-31. [PMID: 7883950 PMCID: PMC441436 DOI: 10.1172/jci117747] [Citation(s) in RCA: 102] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Enterotoxin A is one of the major virulence factors of Clostridium difficile, and the causative agent of antibiotic-associated pseudomembranous colitis. In cell culture (NIH-3T3, rat basophilic leukemia cells) toxin A inhibits Clostridium botulinum ADP-ribosyltransferase C3 (C3)-catalyzed ADP-ribosylation of the low molecular mass GTP-binding Rho proteins. Rho participates in the regulation of the microfilament cytoskeleton. Decrease in ADP-ribosylation of Rho occurs in a time- and concentration-dependent manner and precedes the toxin A-induced destruction of the actin cytoskeleton. Action of toxin A is not due to proteolytical degradation of Rho or to an inherent ADP-ribosyltransferase activity of toxin A. Toxin A-induced decrease in ADP-ribosylation is observed also in cell lysates and with recombinant RhoA protein. A heat stable low molecular mass cytosolic factor is essential for the toxin effect on Rho. Thus, the enterotoxin (toxin A) resembles the effects of the C. difficile cytotoxin (toxin B) on Rho proteins (Just, I., G. Fritz, K. Aktories, M. Giry, M. R. Popoff, P. Boquet, S. Hegenbath, and C. Von Eichel-Streiber. 1994. J. Biol. Chem. 269:10706-10712). The data indicate that despite different in vivo effects, toxin A and toxin B act on the same cellular target protein Rho to elicit their toxic effects.
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Affiliation(s)
- I Just
- Institut für Pharmakologie und Toxikologie, Universität des Saarlandes, Homburg, Germany
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Affiliation(s)
- K Aktories
- Institute of Pharmacology and Toxicology, Albert-Ludwigs University, Freiburg, Germany
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Aktories K. Clostridial ADP-ribosylating toxins: effects on ATP and GTP-binding proteins. Mol Cell Biochem 1994; 138:167-76. [PMID: 7898461 DOI: 10.1007/bf00928459] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The actin cytoskeleton appears to be as the cellular target of various clostridial ADP-ribosyltransferases which have been described during recent years. Clostridium botulinum C2 toxin, Clostridium perfringens iota toxin and Clostridium spiroforme toxin ADP-ribosylate actin monomers and inhibit actin polymerization. Clostridium botulinum exoenzyme C3 and Clostridium limosum exoenzyme ADP-ribosylate the low-molecular-mass GTP-binding proteins of the Rho family, which participate in the regulation of the actin cytoskeleton. ADP-ribosylation inactivates the regulatory Rho proteins and disturbs the organization of the actin cytoskeleton.
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Affiliation(s)
- K Aktories
- Institut für Pharmakologie und Toxikologie, Universität des Saarlandes, Homburg-Saar, Germany
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Fritz G, Just I, Wollenberg P, Aktories K. Differentiation-induced increase in Clostridium botulinum C3 exoenzyme-catalyzed ADP-ribosylation of the small GTP-binding protein Rho. EUROPEAN JOURNAL OF BIOCHEMISTRY 1994; 223:909-16. [PMID: 8055968 DOI: 10.1111/j.1432-1033.1994.tb19068.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The specific [32P]ADP-ribosylation by Clostridium botulinum exoenzyme C3 was used to study differentiation-dependent changes in the regulation of the low-molecular-mass GTP-binding protein Rho. Differentiation of F9 teratocarcinoma cells to neuronal-like cells by treatment with retinoic acid and dibutyryl-adenosine 3',5'-monophosphate [(Bt)2cAMP] increased the C3-catalyzed ADP-ribosylation of RhoA proteins in cytosolic and membrane fractions by about threefold and sixfold, respectively. Phenotypical differentiation of F9 cells was not required for increase in ADP-ribosylation. Increase in ADP-ribosylation after (Bt)2cAMP and retinoic acid treatments was blocked by cycloheximide, indicating the requirement of protein biosynthesis. As deduced from specific rho mRNA amounts and from Western analysis with a monoclonal RhoA antibody, the stimulation in the [32P]ADP-ribosylation of Rho was not caused by an increased de-novo synthesis of Rho proteins. GDP increased the ADP-ribosylation of membrane-associated Rho from non-differentiated, but not from differentiated F9 cells. GTP[S] decreased ADP-ribosylation of membranous Rho from differentiated and much less from non-differentiated F9 cells. Differentiation-dependent increase in ADP-ribosylation of cytosolic Rho was reversed by protein phosphatase type-1. Treatment with SDS (0.01%) which releases Rho from complexation with guanine nucleotide dissociation inhibitor, increased ADP-ribosylation both in differentiated and non-differentiated cells, indicating no differentiation-specific change of such complexes. In total, our data indicate that the induction of the differentiation process in F9 cells is accompanied by changes in the regulation of cytosolic and membrane-associated Rho proteins.
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Affiliation(s)
- G Fritz
- Institut für Pharmakologie und Toxikologie, Universität des Saarlandes, Homburg, Germany
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Fritz G, Aktories K. ADP-ribosylation of Rho proteins by Clostridium botulinum exoenzyme C3 is influenced by phosphorylation of Rho-associated factors. Biochem J 1994; 300 ( Pt 1):133-9. [PMID: 8198524 PMCID: PMC1138134 DOI: 10.1042/bj3000133] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Specific [32P]ADP-ribosylation by Clostridium botulinum exoenzyme C3 was used to study the involvement of phosphorylation in the regulation of the low-molecular-mass GTP-binding protein Rho. Dephosphorylation of CHO cell extracts by alkaline phosphatase treatment resulted in a 80-90% reduction in the C3-catalysed [32P]ADP-ribosylation of Rho proteins in both cytosolic and membrane fractions. Similar results were obtained after dephosphorylation with protein phosphatase type-1 from bovine retina, whereas type-2B and type-2C phosphatases had no effect on the level of subsequent [32P]ADP-ribosylation of Rho by C3. Incubation of CHO cell lysate under phosphorylation conditions increased the subsequent C3-mediated [32P]ADP-ribosylation of Rho proteins. The protein kinase inhibitors H7 and H9 had no effect on [32P]ADP-ribosylation at concentrations which are specific for inhibition of protein kinase A or C. Recombinant glutathione S-transferase-RhoA fusion protein (GST-RhoA) was phosphorylated by protein kinase A; however, the phosphorylation had no stimulatory effect on the ADP-ribosylation of GST-RhoA by C3. An approx. 48 kDa phosphoprotein was identified which bound specifically to recombinant GST-RhoA fusion protein. By gel-permeation chromatography, Rho-containing complexes of approx. 50 kDa and 130-170 kDa were detected. The ADP-ribosylation of Rho in the 130-170 kDa complex was reduced by alkaline phosphatase pretreatment. The data suggest that Rho activity is influenced by phosphorylation of Rho-associated regulatory factors. Phosphorylation/dephosphorylation of these Rho-regulating factors appears to alter the ability of Rho to serve as a substrate for C3-induced [32P]ADP-ribosylation.
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Affiliation(s)
- G Fritz
- Institut für Pharmakologie und Toxikologie, Universität des Saarlandes, Homburg, Germany
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Koch G, Norgauer J, Aktories K. ADP-ribosylation of the GTP-binding protein Rho by Clostridium limosum exoenzyme affects basal, but not N-formyl-peptide-stimulated, actin polymerization in human myeloid leukaemic (HL60) cells. Biochem J 1994; 299 ( Pt 3):775-9. [PMID: 8192667 PMCID: PMC1138088 DOI: 10.1042/bj2990775] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Treatment of human myeloid leukaemic (HL60) cells with Clostridium limosum exoenzyme, which inactivates the small GTP-binding protein Rho by ADP-ribosylation, decreased the basal F-actin content. Inhibition of F-actin occurred after long-term treatment (24 h) of intact HL60 cells or after introduction of the toxin by electropermeabilization in a toxin-concentration-dependent manner. Concomitantly with the decrease in the basal F-actin content, the GTP-binding protein Rho was ADP-ribosylated in intact cells. However, Clostridium limosum toxin had no inhibitory effect on N-formyl-peptide-induced actin polymerization. Moreover, the relative N-formyl-peptide-stimulated polymerization was substantially enhanced in cells treated with Clostridium limosum transferase. In contrast with Clostridium limosum exoenzyme, component C21 of the Clostridium botulinum C2 toxin, which ADP-ribosylates G-actin, depolymerized basal F-actin and inhibited N-formyl-peptide-induced actin polymerization in electropermeabilized HL60 cells. These findings indicate that Rho proteins are involved in the basal, but not the ligand-evoked, actin polymerization in HL60 cells.
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Affiliation(s)
- G Koch
- Institut für Pharmakologie und Toxikologie, Universität des Saarlandes, Homburg-Saar, Germany
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