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Balderson B, Fane M, Harvey TJ, Piper M, Smith A, Bodén M. Systematic analysis of the transcriptional landscape of melanoma reveals drug-target expression plasticity. Brief Funct Genomics 2024:elad055. [PMID: 38183207 DOI: 10.1093/bfgp/elad055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 10/25/2023] [Accepted: 12/04/2023] [Indexed: 01/07/2024] Open
Abstract
Metastatic melanoma originates from melanocytes of the skin. Melanoma metastasis results in poor treatment prognosis for patients and is associated with epigenetic and transcriptional changes that reflect the developmental program of melanocyte differentiation from neural crest stem cells. Several studies have explored melanoma transcriptional heterogeneity using microarray, bulk and single-cell RNA-sequencing technologies to derive data-driven models of the transcriptional-state change which occurs during melanoma progression. No study has systematically examined how different models of melanoma progression derived from different data types, technologies and biological conditions compare. Here, we perform a cross-sectional study to identify averaging effects of bulk-based studies that mask and distort apparent melanoma transcriptional heterogeneity; we describe new transcriptionally distinct melanoma cell states, identify differential co-expression of genes between studies and examine the effects of predicted drug susceptibilities of different cell states between studies. Importantly, we observe considerable variability in drug-target gene expression between studies, indicating potential transcriptional plasticity of melanoma to down-regulate these drug targets and thereby circumvent treatment. Overall, observed differences in gene co-expression and predicted drug susceptibility between studies suggest bulk-based transcriptional measurements do not reliably gauge heterogeneity and that melanoma transcriptional plasticity is greater than described when studies are considered in isolation.
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Affiliation(s)
- Brad Balderson
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072 Queensland, Australia
| | - Mitchell Fane
- Fox Chase Cancer Centre, Philadelphia, 19019 Pennsylvania, United States of America
| | - Tracey J Harvey
- School of Biomedical Sciences, University of Queensland, Brisbane, 4072 Queensland, Australia
| | - Michael Piper
- School of Biomedical Sciences, University of Queensland, Brisbane, 4072 Queensland, Australia
| | - Aaron Smith
- School of Biomedical Sciences, Queensland University of Technology, Brisbane, 4072 Queensland, Australia
| | - Mikael Bodén
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072 Queensland, Australia
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2
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Cossar PJ, Cardoso D, Mathwin D, Russell CC, Chiew B, Hamilton MP, Baker JR, Young KA, Chau N, Robinson PJ, McCluskey A. Wiskostatin and other carbazole scaffolds as off target inhibitors of dynamin I GTPase activity and endocytosis. Eur J Med Chem 2023; 247:115001. [PMID: 36577213 DOI: 10.1016/j.ejmech.2022.115001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 11/30/2022] [Accepted: 11/30/2022] [Indexed: 12/23/2022]
Abstract
Wiskostatin (1-(3,6-dibromo-9H-carbazol-9-yl)-3-(dimethylamino)propan-2-ol) (1) is a carbazole-based compound reported as a specific and relatively potent inhibitor of the N-WASP actin remodelling complex (S-isomer EC50 = 4.35 μM; R-isomer EC50 = 3.44 μM). An NMR solution structure showed that wiskostatin interacts with a cleft in the regulatory GTPase binding domain of N-WASP. However, numerous studies have reported wiskostatin's actions on membrane transport and cytokinesis that are independent of the N-WASP-Arp2/3 complex pathway, but offer limited alternative explanation. The large GTPase, dynamin has established functional roles in these pathways. This study reveals that wiskostatin and its analogues, as well as other carbazole-based compounds, are inhibitors of helical dynamin GTPase activity and endocytosis. We characterise the effects of wiskostatin on in vitro dynamin GTPase activity, in-cell endocytosis, and determine the importance of wiskostatin functional groups on these activities through design and synthesis of libraries of wiskostatin analogues. We also examine whether other carbazole-based scaffolds frequently used in research or the clinic also modulate dynamin and endocytosis. Understanding off-targets for compounds used as research tools is important to be able to confidently interpret their action on biological systems, particularly when the target and off-targets affect overlapping mechanisms (e.g. cytokinesis and endocytosis). Herein we demonstrate that wiskostatin is a dynamin inhibitor (IC50 20.7 ± 1.2 μM) and a potent inhibitor of clathrin mediated endocytosis (IC50 = 6.9 ± 0.3 μM). Synthesis of wiskostatin analogues gave rise to 1-(9H-carbazol-9-yl)-3-((4-methylbenzyl)amino)propan-2-ol (35) and 1-(9H-carbazol-9-yl)-3-((4-chlorobenzyl)amino)propan-2-ol (43) as potent dynamin inhibitors (IC50 = 1.0 ± 0.2 μM), and (S)-1-(3,6-dibromo-9H-carbazol-9-yl)-3-(dimethylamino)propan-2-ol (8a) and (R)-1-(3,6-dibromo-9H-carbazol-9-yl)-3-(dimethylamino)propan-2-ol (8b) that are amongst the most potent inhibitors of clathrin mediated endocytosis yet reported (IC50 = 2.3 ± 3.3 and 2.1 ± 1.7 μM, respectively).
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Affiliation(s)
- Peter J Cossar
- Chemistry, School of Environmental & Life Sciences, The University of Newcastle, University Drive, Callaghan NSW, 2308, Australia
| | - David Cardoso
- Cell Signalling Unit, Children's Medical Research Institute, The University of Sydney, Sydney, NSW, 2145, Australia
| | - Daniel Mathwin
- Chemistry, School of Environmental & Life Sciences, The University of Newcastle, University Drive, Callaghan NSW, 2308, Australia
| | - Cecilia C Russell
- Chemistry, School of Environmental & Life Sciences, The University of Newcastle, University Drive, Callaghan NSW, 2308, Australia
| | - Beatrice Chiew
- Chemistry, School of Environmental & Life Sciences, The University of Newcastle, University Drive, Callaghan NSW, 2308, Australia
| | - Michael P Hamilton
- Chemistry, School of Environmental & Life Sciences, The University of Newcastle, University Drive, Callaghan NSW, 2308, Australia
| | - Jennifer R Baker
- Chemistry, School of Environmental & Life Sciences, The University of Newcastle, University Drive, Callaghan NSW, 2308, Australia
| | - Kelly A Young
- Chemistry, School of Environmental & Life Sciences, The University of Newcastle, University Drive, Callaghan NSW, 2308, Australia
| | - Ngoc Chau
- Cell Signalling Unit, Children's Medical Research Institute, The University of Sydney, Sydney, NSW, 2145, Australia
| | - Phillip J Robinson
- Cell Signalling Unit, Children's Medical Research Institute, The University of Sydney, Sydney, NSW, 2145, Australia
| | - Adam McCluskey
- Chemistry, School of Environmental & Life Sciences, The University of Newcastle, University Drive, Callaghan NSW, 2308, Australia.
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3
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Li Y, Wang D, Ge H, Güngör C, Gong X, Chen Y. Cytoskeletal and Cytoskeleton-Associated Proteins: Key Regulators of Cancer Stem Cell Properties. Pharmaceuticals (Basel) 2022; 15:1369. [PMID: 36355541 PMCID: PMC9698833 DOI: 10.3390/ph15111369] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2022] [Revised: 11/02/2022] [Accepted: 11/06/2022] [Indexed: 08/08/2023] Open
Abstract
Cancer stem cells (CSCs) are a subpopulation of cancer cells possessing stemness characteristics that are closely associated with tumor proliferation, recurrence and resistance to therapy. Recent studies have shown that different cytoskeletal components and remodeling processes have a profound impact on the behavior of CSCs. In this review, we outline the different cytoskeletal components regulating the properties of CSCs and discuss current and ongoing therapeutic strategies targeting the cytoskeleton. Given the many challenges currently faced in targeted cancer therapy, a deeper comprehension of the molecular events involved in the interaction of the cytoskeleton and CSCs will help us identify more effective therapeutic strategies to eliminate CSCs and ultimately improve patient survival.
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Affiliation(s)
- Yuqiang Li
- Department of General Surgery, Xiangya Hospital, Central South University, Changsha 410008, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha 410008, China
- NHC Key Laboratory of Cancer Proteomics, Laboratory of Structural Biology, Xiangya Hospital, Central South University, Changsha 410008, China
| | - Dan Wang
- Department of General Surgery, Xiangya Hospital, Central South University, Changsha 410008, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha 410008, China
- Department of General Visceral and Thoracic Surgery, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Heming Ge
- Department of General Surgery, Xiangya Hospital, Central South University, Changsha 410008, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha 410008, China
- Department of General Visceral and Thoracic Surgery, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Cenap Güngör
- Department of General Visceral and Thoracic Surgery, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Xuejun Gong
- Department of General Surgery, Xiangya Hospital, Central South University, Changsha 410008, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha 410008, China
| | - Yongheng Chen
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha 410008, China
- NHC Key Laboratory of Cancer Proteomics, Laboratory of Structural Biology, Xiangya Hospital, Central South University, Changsha 410008, China
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4
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Kramer DA, Piper HK, Chen B. WASP family proteins: Molecular mechanisms and implications in human disease. Eur J Cell Biol 2022; 101:151244. [PMID: 35667337 PMCID: PMC9357188 DOI: 10.1016/j.ejcb.2022.151244] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Revised: 05/25/2022] [Accepted: 05/27/2022] [Indexed: 02/08/2023] Open
Abstract
Proteins of the Wiskott-Aldrich syndrome protein (WASP) family play a central role in regulating actin cytoskeletal dynamics in a wide range of cellular processes. Genetic mutations or misregulation of these proteins are tightly associated with many diseases. The WASP-family proteins act by transmitting various upstream signals to their conserved WH2-Central-Acidic (WCA) peptide sequence at the C-terminus, which in turn binds to the Arp2/3 complex to stimulate the formation of branched actin networks at membranes. Despite this common feature, the regulatory mechanisms and cellular functions of distinct WASP-family proteins are very different. Here, we summarize and clarify our current understanding of WASP-family proteins and how disruption of their functions is related to human disease.
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Affiliation(s)
- Daniel A Kramer
- Roy J. Carver Department of Biochemistry, Biophysics & Molecular Biology, Iowa State University, 2437 Pammel Drive, Ames, IA 50011, USA
| | - Hannah K Piper
- Roy J. Carver Department of Biochemistry, Biophysics & Molecular Biology, Iowa State University, 2437 Pammel Drive, Ames, IA 50011, USA
| | - Baoyu Chen
- Roy J. Carver Department of Biochemistry, Biophysics & Molecular Biology, Iowa State University, 2437 Pammel Drive, Ames, IA 50011, USA.
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5
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Mageswaran SK, Yang WY, Chakrabarty Y, Oikonomou CM, Jensen GJ. A cryo-electron tomography workflow reveals protrusion-mediated shedding on injured plasma membrane. SCIENCE ADVANCES 2021; 7:7/13/eabc6345. [PMID: 33771860 PMCID: PMC7997517 DOI: 10.1126/sciadv.abc6345] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 02/09/2021] [Indexed: 06/12/2023]
Abstract
Cryo-electron tomography (cryo-ET) provides structural context to molecular mechanisms underlying biological processes. Although straightforward to implement for studying stable macromolecular complexes, using it to locate short-lived structures and events can be impractical. A combination of live-cell microscopy, correlative light and electron microscopy, and cryo-ET will alleviate this issue. We developed a workflow combining the three to study the ubiquitous and dynamic process of shedding in response to plasma membrane damage in HeLa cells. We found filopodia-like protrusions enriched at damage sites and acting as scaffolds for shedding, which involves F-actin dynamics, myosin-1a, and vacuolar protein sorting 4B (a component of the 'endosomal sorting complex required for transport' machinery). Overall, shedding is more complex than current models of vesiculation from flat membranes. Its similarities to constitutive shedding in enterocytes argue for a conserved mechanism. Our workflow can also be adapted to study other damage response pathways and dynamic cellular events.
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Affiliation(s)
- Shrawan Kumar Mageswaran
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
- Department of Biophysics and Biochemistry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Wei Yuan Yang
- Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan.
| | - Yogaditya Chakrabarty
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Catherine M Oikonomou
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Grant J Jensen
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84604, USA
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6
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Biber G, Ben-Shmuel A, Sabag B, Barda-Saad M. Actin regulators in cancer progression and metastases: From structure and function to cytoskeletal dynamics. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2020; 356:131-196. [PMID: 33066873 DOI: 10.1016/bs.ircmb.2020.05.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The cytoskeleton is a central factor contributing to various hallmarks of cancer. In recent years, there has been increasing evidence demonstrating the involvement of actin regulatory proteins in malignancy, and their dysregulation was shown to predict poor clinical prognosis. Although enhanced cytoskeletal activity is often associated with cancer progression, the expression of several inducers of actin polymerization is remarkably reduced in certain malignancies, and it is not completely clear how these changes promote tumorigenesis and metastases. The complexities involved in cytoskeletal induction of cancer progression therefore pose considerable difficulties for therapeutic intervention; it is not always clear which cytoskeletal regulator should be targeted in order to impede cancer progression, and whether this targeting may inadvertently enhance alternative invasive pathways which can aggravate tumor growth. The entire constellation of cytoskeletal machineries in eukaryotic cells are numerous and complex; the system is comprised of and regulated by hundreds of proteins, which could not be covered in a single review. Therefore, we will focus here on the actin cytoskeleton, which encompasses the biological machinery behind most of the key cellular functions altered in cancer, with specific emphasis on actin nucleating factors and nucleation-promoting factors. Finally, we discuss current therapeutic strategies for cancer which aim to target the cytoskeleton.
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Affiliation(s)
- G Biber
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
| | - A Ben-Shmuel
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
| | - B Sabag
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
| | - M Barda-Saad
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel.
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7
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Sun L, Cao X, Lechuga S, Feygin A, Naydenov NG, Ivanov AI. A Septin Cytoskeleton-Targeting Small Molecule, Forchlorfenuron, Inhibits Epithelial Migration via Septin-Independent Perturbation of Cellular Signaling. Cells 2019; 9:cells9010084. [PMID: 31905721 PMCID: PMC7016606 DOI: 10.3390/cells9010084] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 12/24/2019] [Accepted: 12/26/2019] [Indexed: 12/19/2022] Open
Abstract
Septins are GTP-binding proteins that self-assemble into high-order cytoskeletal structures, filaments, and rings. The septin cytoskeleton has a number of cellular functions, including regulation of cytokinesis, cell migration, vesicle trafficking, and receptor signaling. A plant cytokinin, forchlorfenuron (FCF), interacts with septin subunits, resulting in the altered organization of the septin cytoskeleton. Although FCF has been extensively used to examine the roles of septins in various cellular processes, its specificity, and possible off-target effects in vertebrate systems, has not been investigated. In the present study, we demonstrate that FCF inhibits spontaneous, as well as hepatocyte growth factor-induced, migration of HT-29 and DU145 human epithelial cells. Additionally, FCF increases paracellular permeability of HT-29 cell monolayers. These inhibitory effects of FCF persist in epithelial cells where the septin cytoskeleton has been disassembled by either CRISPR/Cas9-mediated knockout or siRNA-mediated knockdown of septin 7, insinuating off-target effects of FCF. Biochemical analysis reveals that FCF-dependent inhibition of the motility of control and septin-depleted cells is accompanied by decreased expression of the c-Jun transcription factor and inhibited ERK activity. The described off-target effects of FCF strongly suggests that caution is warranted while using this compound to examine the biological functions of septins in cellular systems and model organisms.
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Affiliation(s)
- Lei Sun
- Department of Inflammation and Immunity, Lerner Research Institute of Cleveland Clinic Foundation, Cleveland, OH 44195, USA; (L.S.); (X.C.); (S.L.); (N.G.N.)
| | - Xuelei Cao
- Department of Inflammation and Immunity, Lerner Research Institute of Cleveland Clinic Foundation, Cleveland, OH 44195, USA; (L.S.); (X.C.); (S.L.); (N.G.N.)
| | - Susana Lechuga
- Department of Inflammation and Immunity, Lerner Research Institute of Cleveland Clinic Foundation, Cleveland, OH 44195, USA; (L.S.); (X.C.); (S.L.); (N.G.N.)
| | - Alex Feygin
- School of Nursing, Virginia Commonwealth University School of Nursing, Richmond, VA 23298, USA;
| | - Nayden G. Naydenov
- Department of Inflammation and Immunity, Lerner Research Institute of Cleveland Clinic Foundation, Cleveland, OH 44195, USA; (L.S.); (X.C.); (S.L.); (N.G.N.)
| | - Andrei I. Ivanov
- Department of Inflammation and Immunity, Lerner Research Institute of Cleveland Clinic Foundation, Cleveland, OH 44195, USA; (L.S.); (X.C.); (S.L.); (N.G.N.)
- Correspondence: ; Tel.: +1-216-444-5620
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8
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Butler-Fernández KM, Ramos Z, Francis-Malavé AM, Bloom J, Dharmawardhane S, Hernández E. Synthesis, Anti-Cancer and Anti-Migratory Evaluation of 3,6-Dibromocarbazole and 5-Bromoindole Derivatives. Molecules 2019; 24:E2686. [PMID: 31344865 PMCID: PMC6696445 DOI: 10.3390/molecules24152686] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 07/18/2019] [Accepted: 07/19/2019] [Indexed: 11/16/2022] Open
Abstract
In this study, a new series of N-alkyl-3,6-dibromocarbazole and N-alkyl-5-bromoindole derivatives have been synthesized and evaluated in vitro as anti-cancer and anti-migration agents. Cytotoxic and anti-migratory effects of these compounds were evaluated in MCF-7 and MDA-MB-231 breast cancer cell lines and an insight on the structure-activity relationship was developed. Preliminary investigations of their anti-cancer activity demonstrated that several compounds have moderate antiproliferative effects on cancer cell lines with GI50 values in the range of 4.7-32.2 µM. Moreover, carbazole derivatives 10, 14, 15, 23, and 24 inhibit migration activity of metastatic cell line MDA-MB-231 in the range of 18-20%. The effect of compounds 10, 14, and 15 in extension of invadopodia and filopodia was evaluated by fluorescence microscopy and results demonstrated a reduction in actin-based cell extensions by compounds 10 and 15.
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Affiliation(s)
- Krystal M Butler-Fernández
- Department of Pharmaceutical Sciences, University of Puerto Rico, School of Pharmacy, San Juan 00936, Puerto Rico
| | - Zulma Ramos
- Department of Pharmaceutical Sciences, University of Puerto Rico, School of Pharmacy, San Juan 00936, Puerto Rico
| | - Adela M Francis-Malavé
- Department of Biology, College of Natural Sciences, University of Puerto Rico, San Juan 00931, Puerto Rico
| | - Joseph Bloom
- Department of Pharmaceutical Sciences, University of Puerto Rico, School of Pharmacy, San Juan 00936, Puerto Rico
| | - Suranganie Dharmawardhane
- Department of Biochemistry, University of Puerto Rico, School of Medicine, San Juan 00936, Puerto Rico
| | - Eliud Hernández
- Department of Pharmaceutical Sciences, University of Puerto Rico, School of Pharmacy, San Juan 00936, Puerto Rico.
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9
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Khasa R, Vaidya A, Vrati S, Kalia M. Membrane trafficking RNA interference screen identifies a crucial role of the clathrin endocytic pathway and ARP2/3 complex for Japanese encephalitis virus infection in HeLa cells. J Gen Virol 2019; 100:176-186. [DOI: 10.1099/jgv.0.001182] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Affiliation(s)
- Renu Khasa
- 1Vaccine and Infectious Disease Research Centre, Translational Health Science and Technology Institute, NCR Biotech Science Cluster, Faridabad, Haryana, India
- 2Symbiosis School of Biological Sciences, Symbiosis International (Deemed University), Pune, Maharashtra, India
| | - Anuradha Vaidya
- 2Symbiosis School of Biological Sciences, Symbiosis International (Deemed University), Pune, Maharashtra, India
| | - Sudhanshu Vrati
- 1Vaccine and Infectious Disease Research Centre, Translational Health Science and Technology Institute, NCR Biotech Science Cluster, Faridabad, Haryana, India
- 3Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, Haryana, India
| | - Manjula Kalia
- 1Vaccine and Infectious Disease Research Centre, Translational Health Science and Technology Institute, NCR Biotech Science Cluster, Faridabad, Haryana, India
- 3Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, Haryana, India
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10
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Rajasekaran SS, Illies C, Shears SB, Wang H, Ayala TS, Martins JO, Daré E, Berggren PO, Barker CJ. Protein kinase- and lipase inhibitors of inositide metabolism deplete IP 7 indirectly in pancreatic β-cells: Off-target effects on cellular bioenergetics and direct effects on IP6K activity. Cell Signal 2017; 42:127-133. [PMID: 29042286 PMCID: PMC5765549 DOI: 10.1016/j.cellsig.2017.10.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 10/11/2017] [Accepted: 10/13/2017] [Indexed: 12/22/2022]
Abstract
Inositol pyrophosphates have emerged as important regulators of many critical cellular processes from vesicle trafficking and cytoskeletal rearrangement to telomere length regulation and apoptosis. We have previously demonstrated that 5-di-phosphoinositol pentakisphosphate, IP7, is at a high level in pancreatic β-cells and is important for insulin exocytosis. To better understand IP7 regulation in β-cells, we used an insulin secreting cell line, HIT-T15, to screen a number of different pharmacological inhibitors of inositide metabolism for their impact on cellular IP7. Although the inhibitors have diverse targets, they all perturbed IP7 levels. This made us suspicious that indirect, off-target effects of the inhibitors could be involved. It is known that IP7 levels are decreased by metabolic poisons. The fact that the inositol hexakisphosphate kinases (IP6Ks) have a high Km for ATP makes IP7 synthesis potentially vulnerable to ATP depletion. Furthermore, many kinase inhibitors are targeted to the ATP binding site of kinases, but given the similarity of such sites, high specificity is difficult to achieve. Here, we show that IP7 concentrations in HIT-T15 cells were reduced by inhibitors of PI3K (wortmannin, LY294002), PI4K (Phenylarsine Oxide, PAO), PLC (U73122) and the insulin receptor (HNMPA). Each of these inhibitors also decreased the ATP/ADP ratio. Thus reagents that compromise energy metabolism reduce IP7 indirectly. Additionally, PAO, U73122 and LY294002 also directly inhibited the activity of purified IP6K. These data are of particular concern for those studying signal transduction in pancreatic β-cells, but also highlight the fact that employment of these inhibitors could have erroneously suggested the involvement of key signal transduction pathways in various cellular processes. Conversely, IP7’s role in cellular signal transduction is likely to have been underestimated. In pancreatic β-cells several inhibitors of signal transduction reduce IP7 levels. There is a positive correlation between IP7 reduction and decrease in ATP/ADP. Inhibitors deplete IP7 levels indirectly by decreasing ATP/ADP levels. Some purportedly specific cell-signaling inhibitors directly target IP6K activity. Caution is required in interpreting data obtained using inhibitors of inositide metabolism.
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Affiliation(s)
- Subu Surendran Rajasekaran
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, SE-171 76 Stockholm, Sweden
| | - Christopher Illies
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, SE-171 76 Stockholm, Sweden
| | - Stephen B Shears
- Signal Transduction Laboratory/Inositol Signaling Group, NIEHS, Building 101, Room F239, 111 T.W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Huanchen Wang
- Signal Transduction Laboratory/Inositol Signaling Group, NIEHS, Building 101, Room F239, 111 T.W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Thais S Ayala
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, SE-171 76 Stockholm, Sweden; Laboratory of Immunoendocrinology, Department of Clinical and Toxicological Analyses, Faculty of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil
| | - Joilson O Martins
- Laboratory of Immunoendocrinology, Department of Clinical and Toxicological Analyses, Faculty of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil
| | - Elisabetta Daré
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, SE-171 76 Stockholm, Sweden
| | - Per-Olof Berggren
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, SE-171 76 Stockholm, Sweden.
| | - Christopher J Barker
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, SE-171 76 Stockholm, Sweden.
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11
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Tunduguru R, Zhang J, Aslamy A, Salunkhe VA, Brozinick JT, Elmendorf JS, Thurmond DC. The actin-related p41ARC subunit contributes to p21-activated kinase-1 (PAK1)-mediated glucose uptake into skeletal muscle cells. J Biol Chem 2017; 292:19034-19043. [PMID: 28972183 DOI: 10.1074/jbc.m117.801340] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 09/21/2017] [Indexed: 02/04/2023] Open
Abstract
Defects in translocation of the glucose transporter GLUT4 are associated with peripheral insulin resistance, preclinical diabetes, and progression to type 2 diabetes. GLUT4 recruitment to the plasma membrane of skeletal muscle cells requires F-actin remodeling. Insulin signaling in muscle requires p21-activated kinase-1 (PAK1), whose downstream signaling triggers actin remodeling, which promotes GLUT4 vesicle translocation and glucose uptake into skeletal muscle cells. Actin remodeling is a cyclic process, and although PAK1 is known to initiate changes to the cortical actin-binding protein cofilin to stimulate the depolymerizing arm of the cycle, how PAK1 might trigger the polymerizing arm of the cycle remains unresolved. Toward this, we investigated whether PAK1 contributes to the mechanisms involving the actin-binding and -polymerizing proteins neural Wiskott-Aldrich syndrome protein (N-WASP), cortactin, and ARP2/3 subunits. We found that the actin-polymerizing ARP2/3 subunit p41ARC is a PAK1 substrate in skeletal muscle cells. Moreover, co-immunoprecipitation experiments revealed that insulin stimulates p41ARC phosphorylation and increases its association with N-WASP coordinately with the associations of N-WASP with cortactin and actin. Importantly, all of these associations were ablated by the PAK inhibitor IPA3, suggesting that PAK1 activation lies upstream of these actin-polymerizing complexes. Using the N-WASP inhibitor wiskostatin, we further demonstrated that N-WASP is required for localized F-actin polymerization, GLUT4 vesicle translocation, and glucose uptake. These results expand the model of insulin-stimulated glucose uptake in skeletal muscle cells by implicating p41ARC as a new component of the insulin-signaling cascade and connecting PAK1 signaling to N-WASP-cortactin-mediated actin polymerization and GLUT4 vesicle translocation.
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Affiliation(s)
- Ragadeepthi Tunduguru
- From the Departments of Biochemistry and Molecular Biology and.,the Department of Molecular and Cellular Endocrinology, Diabetes and Metabolism Research Institute and Beckman Research Institute of the City of Hope, Duarte, California 91010, and
| | - Jing Zhang
- the Department of Molecular and Cellular Endocrinology, Diabetes and Metabolism Research Institute and Beckman Research Institute of the City of Hope, Duarte, California 91010, and
| | - Arianne Aslamy
- the Department of Molecular and Cellular Endocrinology, Diabetes and Metabolism Research Institute and Beckman Research Institute of the City of Hope, Duarte, California 91010, and.,Cellular and Integrative Physiology, Center for Diabetes and Metabolic Diseases,Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Vishal A Salunkhe
- the Department of Molecular and Cellular Endocrinology, Diabetes and Metabolism Research Institute and Beckman Research Institute of the City of Hope, Duarte, California 91010, and
| | | | - Jeffrey S Elmendorf
- From the Departments of Biochemistry and Molecular Biology and.,Cellular and Integrative Physiology, Center for Diabetes and Metabolic Diseases,Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Debbie C Thurmond
- From the Departments of Biochemistry and Molecular Biology and .,the Department of Molecular and Cellular Endocrinology, Diabetes and Metabolism Research Institute and Beckman Research Institute of the City of Hope, Duarte, California 91010, and.,Cellular and Integrative Physiology, Center for Diabetes and Metabolic Diseases,Indiana University School of Medicine, Indianapolis, Indiana 46202
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12
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Fritz-Laylin LK, Lord SJ, Mullins RD. WASP and SCAR are evolutionarily conserved in actin-filled pseudopod-based motility. J Cell Biol 2017; 216:1673-1688. [PMID: 28473602 PMCID: PMC5461030 DOI: 10.1083/jcb.201701074] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Revised: 03/12/2017] [Accepted: 03/31/2017] [Indexed: 01/08/2023] Open
Abstract
Eukaryotic cells use diverse cellular mechanisms to crawl through complex environments. Fritz-Laylin et al. define α-motility as a mode of migration associated with dynamic, actin-filled pseudopods and show that WASP and SCAR constitute an evolutionarily conserved genetic signature of α-motility. Diverse eukaryotic cells crawl through complex environments using distinct modes of migration. To understand the underlying mechanisms and their evolutionary relationships, we must define each mode and identify its phenotypic and molecular markers. In this study, we focus on a widely dispersed migration mode characterized by dynamic actin-filled pseudopods that we call “α-motility.” Mining genomic data reveals a clear trend: only organisms with both WASP and SCAR/WAVE—activators of branched actin assembly—make actin-filled pseudopods. Although SCAR has been shown to drive pseudopod formation, WASP’s role in this process is controversial. We hypothesize that these genes collectively represent a genetic signature of α-motility because both are used for pseudopod formation. WASP depletion from human neutrophils confirms that both proteins are involved in explosive actin polymerization, pseudopod formation, and cell migration. WASP and WAVE also colocalize to dynamic signaling structures. Moreover, retention of WASP together with SCAR correctly predicts α-motility in disease-causing chytrid fungi, which we show crawl at >30 µm/min with actin-filled pseudopods. By focusing on one migration mode in many eukaryotes, we identify a genetic marker of pseudopod formation, the morphological feature of α-motility, providing evidence for a widely distributed mode of cell crawling with a single evolutionary origin.
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Affiliation(s)
- Lillian K Fritz-Laylin
- Department of Cellular and Molecular Pharmacology, Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94143
| | - Samuel J Lord
- Department of Cellular and Molecular Pharmacology, Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94143
| | - R Dyche Mullins
- Department of Cellular and Molecular Pharmacology, Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94143
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13
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Mallela SK, Almeida R, Ejsing CS, Conzelmann A. Functions of Ceramide Synthase Paralogs YPR114w and YJR116w of Saccharomyces cerevisiae. PLoS One 2016; 11:e0145831. [PMID: 26752183 PMCID: PMC4713442 DOI: 10.1371/journal.pone.0145831] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 11/04/2015] [Indexed: 12/22/2022] Open
Abstract
Ceramide is synthesized in yeast by two redundant acyl-CoA dependent synthases, Lag1 and Lac1. In lag1∆ lac1∆ cells, free fatty acids and sphingoid bases are elevated, and ceramides are produced through the redundant alkaline ceramidases Ypc1 and Ydc1, working backwards. Even with all four of these genes deleted, cells are surviving and continue to contain small amounts of complex sphingolipids. Here we show that these residual sphingolipids are not synthesized by YPR114w or YJR116w, proteins of unknown function showing a high degree of homology to Lag1 and Lac1. Indeed, the hextuple lag1∆ lac1∆ ypc1∆ ydc1∆ ypr114w∆ yjr116w∆ mutant still contains ceramides and complex sphingolipids. Yjr116w∆ exhibit an oxygen-dependent hypersensitivity to Cu2+ due to an increased mitochondrial production of reactive oxygen species (ROS) and a mitochondrially orchestrated programmed cell death in presence of copper, but also a general copper hypersensitivity that cannot be counteracted by the antioxidant N-acetyl-cysteine (NAC). Myriocin efficiently represses the synthesis of sphingoid bases of ypr114w∆, but not its growth. Both yjr116w∆ and ypr114w∆ have fragmented vacuoles and produce less ROS than wild type, before and after diauxic shift. Ypr114w∆/ypr114w∆ have an increased chronological life span. Thus, Yjr116w and Ypr114w are related, but not functionally redundant.
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Affiliation(s)
- Shamroop K. Mallela
- Division of Biochemistry, Department of Biology, University of Fribourg, Chemin du Musée 10, Fribourg, CH-1700, Switzerland
| | - Reinaldo Almeida
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230, Odense M, Denmark
| | - Christer S. Ejsing
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230, Odense M, Denmark
| | - Andreas Conzelmann
- Division of Biochemistry, Department of Biology, University of Fribourg, Chemin du Musée 10, Fribourg, CH-1700, Switzerland
- * E-mail:
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14
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Actin-Dynamics in Plant Cells: The Function of Actin-Perturbing Substances: Jasplakinolide, Chondramides, Phalloidin, Cytochalasins, and Latrunculins. Methods Mol Biol 2016; 1365:243-61. [PMID: 26498789 DOI: 10.1007/978-1-4939-3124-8_13] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
This chapter gives an overview of the most common F-actin-perturbing substances that are used to study actin dynamics in living plant cells in studies on morphogenesis, motility, organelle movement, or when apoptosis has to be induced. These substances can be divided into two major subclasses: F-actin-stabilizing and -polymerizing substances like jasplakinolide and chondramides and F-actin-severing compounds like chytochalasins and latrunculins. Jasplakinolide was originally isolated form a marine sponge, and can now be synthesized and has become commercially available, which is responsible for its wide distribution as membrane-permeable F-actin-stabilizing and -polymerizing agent, which may even have anticancer activities. Cytochalasins, derived from fungi, show an F-actin-severing function and many derivatives are commercially available (A, B, C, D, E, H, J), also making it a widely used compound for F-actin disruption. The same can be stated for latrunculins (A, B), derived from red sea sponges; however the mode of action is different by binding to G-actin and inhibiting incorporation into the filament. In the case of swinholide a stable complex with actin dimers is formed resulting also in severing of F-actin. For influencing F-actin dynamics in plant cells only membrane permeable drugs are useful in a broad range. We however introduce also the phallotoxins and synthetic derivatives, as they are widely used to visualize F-actin in fixed cells. A particular uptake mechanism has been shown for hepatocytes, but has also been described in siphonal giant algae. In the present chapter the focus is set on F-actin dynamics in plant cells where alterations in cytoplasmic streaming can be particularly well studied; however methods by fluorescence applications including phalloidin and antibody staining as well as immunofluorescence-localization of the inhibitor drugs are given.
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EtpE Binding to DNase X Induces Ehrlichial Entry via CD147 and hnRNP-K Recruitment, Followed by Mobilization of N-WASP and Actin. mBio 2015; 6:e01541-15. [PMID: 26530384 PMCID: PMC4631803 DOI: 10.1128/mbio.01541-15] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Obligate intracellular bacteria, such as Ehrlichia chaffeensis, perish unless they can enter eukaryotic cells. E. chaffeensis is the etiological agent of human monocytic ehrlichiosis, an emerging infectious disease. To infect cells, Ehrlichia uses the C terminus of the outer membrane invasin entry-triggering protein (EtpE) of Ehrlichia (EtpE-C), which directly binds the mammalian cell surface glycosylphosphatidyl inositol-anchored protein, DNase X. How this binding drives Ehrlichia entry is unknown. Here, using affinity pulldown of host cell lysates with recombinant EtpE-C (rEtpE-C), we identified two new human proteins that interact with EtpE-C: CD147 and heterogeneous nuclear ribonucleoprotein K (hnRNP-K). The interaction of CD147 with rEtpE-C was validated by far-Western blotting and coimmunoprecipitation of native EtpE with endogenous CD147. CD147 was ubiquitous on the cell surface and also present around foci of rEtpE-C-coated-bead entry. Functional neutralization of surface-exposed CD147 with a specific antibody inhibited Ehrlichia internalization and infection but not binding. Downregulation of CD147 by short hairpin RNA (shRNA) impaired E. chaffeensis infection. Functional ablation of cytoplasmic hnRNP-K by a nanoscale intracellular antibody markedly attenuated bacterial entry and infection but not binding. EtpE-C also interacted with neuronal Wiskott-Aldrich syndrome protein (N-WASP), which is activated by hnRNP-K. Wiskostatin, which inhibits N-WASP activation, and cytochalasin D, which inhibits actin polymerization, inhibited Ehrlichia entry. Upon incubation with host cell lysate, EtpE-C but not an EtpE N-terminal fragment stimulated in vitro actin polymerization in an N-WASP- and DNase X-dependent manner. Time-lapse video images revealed N-WASP recruitment at EtpE-C-coated bead entry foci. Thus, EtpE-C binding to DNase X drives Ehrlichia entry by engaging CD147 and hnRNP-K and activating N-WASP-dependent actin polymerization. Ehrlichia chaffeensis, an obligate intracellular bacterium, causes a blood-borne disease called human monocytic ehrlichiosis, one of the most prevalent life-threatening emerging tick-transmitted infectious diseases in the United States. The survival of Ehrlichia bacteria, and hence, their ability to cause disease, depends on their specific mode of entry into eukaryotic host cells. Understanding the mechanism by which E. chaffeensis enters cells will create new opportunities for developing effective therapies to prevent bacterial entry and disease in humans. Our findings reveal a novel cellular signaling pathway triggered by an ehrlichial surface protein called EtpE to induce its infectious entry. The results are also important from the viewpoint of human cell physiology because three EtpE-interacting human proteins, DNase X, CD147, and hnRNP-K, are hitherto unknown partners that drive the uptake of small particles, including bacteria, into human cells.
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16
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Rassokhin MA, Pakhomov AG. Cellular regulation of extension and retraction of pseudopod-like blebs produced by nanosecond pulsed electric field (nsPEF). Cell Biochem Biophys 2015; 69:555-66. [PMID: 24488232 DOI: 10.1007/s12013-014-9831-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Recently we described a new phenomenon of anodotropic pseudopod-like blebbing in U937 cells exposed to nanosecond pulsed electric field (nsPEF). In Ca(2+)-free buffer such exposure initiates formation of pseudopod-like blebs (PLBs), protrusive cylindrical cell extensions that are distinct from apoptotic and necrotic blebs. PLBs nucleate predominantly on anode-facing cell pole and extend toward anode during nsPEF exposure. Bleb extension depends on actin polymerization and availability of actin monomers. Inhibition of intracellular Ca(2+), cell contractility, and RhoA produced no effect on PLB initiation. Meanwhile, inhibition of WASP by wiskostatin causes dose-dependent suppression of PLB growth. Soon after the end of nsPEF exposure PLBs lose directionality of growth and then retract. Microtubule toxins nocodazole and paclitaxel did not show immediate effect on PLBs; however, nocodazole increased mobility of intracellular components during PLB extension and retraction. Retraction of PLBs is produced by myosin activation and the corresponding increase in PLB cortex contractility. Inhibition of myosin by blebbistatin reduces retraction while inhibition of RhoA-ROCK pathway by Y-27632 completely prevents retraction. Contraction of PLBs can produce cell translocation resembling active cell movement. Overall, the formation, properties, and life cycle of PLBs share common features with protrusions associated with ameboid cell migration. PLB life cycle may be controlled through activation of WASP by its upstream effectors such as Cdc42 and PIP2, and main ROCK activator-RhoA. Parallels between pseudopod-like blebbing and motility blebbing may provide new insights into their underlying mechanisms.
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Affiliation(s)
- Mikhail A Rassokhin
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, 4211 Monarch Way Ste 300, Norfolk, VA, 23508, USA,
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17
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Involvement of the Cdc42 pathway in CFTR post-translational turnover and in its plasma membrane stability in airway epithelial cells. PLoS One 2015; 10:e0118943. [PMID: 25768293 PMCID: PMC4359135 DOI: 10.1371/journal.pone.0118943] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 01/07/2015] [Indexed: 12/21/2022] Open
Abstract
Cystic fibrosis transmembrane conductance regulator (CFTR) is a chloride channel that is expressed on the apical plasma membrane (PM) of epithelial cells. The most common deleterious allele encodes a trafficking-defective mutant protein undergoing endoplasmic reticulum-associated degradation (ERAD) and presenting lower PM stability. In this study, we investigated the involvement of the Cdc42 pathway in CFTR turnover and trafficking in a human bronchiolar epithelial cell line (CFBE41o-) expressing wild-type CFTR. Cdc42 is a small GTPase of the Rho family that fulfils numerous cell functions, one of which is endocytosis and recycling process via actin cytoskeleton remodelling. When we treated cells with chemical inhibitors such as ML141 against Cdc42 and wiskostatin against the downstream effector N-WASP, we observed that CFTR channel activity was inhibited, in correlation with a decrease in CFTR amount at the cell surface and an increase in dynamin-dependent CFTR endocytosis. Anchoring of CFTR to the cortical cytoskeleton was then presumably impaired by actin disorganization. When we performed siRNA-mediated depletion of Cdc42, actin polymerization was not impacted, but we observed actin-independent consequences upon CFTR. Total and PM CFTR amounts were increased, resulting in greater activation of CFTR. Pulse-chase experiments showed that while CFTR degradation was slowed, CFTR maturation through the Golgi apparatus remained unaffected. In addition, we observed increased stability of CFTR in PM and reduction of its endocytosis. This study highlights the involvement of the Cdc42 pathway at several levels of CFTR biogenesis and trafficking: (i) Cdc42 is implicated in the first steps of CFTR biosynthesis and processing; (ii) it contributes to the stability of CFTR in PM via its anchoring to cortical actin; (iii) it promotes CFTR endocytosis and presumably its sorting toward lysosomal degradation.
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18
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Jeganathan S, Fiorino C, Naik U, Sun HS, Harrison RE. Modulation of osteoclastogenesis with macrophage M1- and M2-inducing stimuli. PLoS One 2014; 9:e104498. [PMID: 25101660 PMCID: PMC4125219 DOI: 10.1371/journal.pone.0104498] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Accepted: 07/14/2014] [Indexed: 12/15/2022] Open
Abstract
Macrophages are generated through the differentiation of monocytes in tissues and they have important functions in innate and adaptive immunity. In addition to their roles as phagocytes, macrophages can be further differentiated, in the presence of receptor activator of nuclear factor kappa-B ligand (RANKL) and macrophage colony-stimulating factor (M-CSF), into osteoclasts (multinucleated giant cells that are responsible for bone resorption). In this work, we set out to characterize whether various inflammatory stimuli, known to induce macrophage polarization, can alter the type of multinucleated giant cell obtained from RANKL differentiation. Following a four-day differentiation protocol, along with lipopolysaccharide (LPS)/interferon gamma (IFNγ) as one stimulus, and interleukin-4 (IL-4) as the other, three types of multinucleated cells were generated. Using various microscopy techniques (bright field, epifluorescence and scanning electron), functional assays, and western blotting for osteoclast markers, we found that, as expected, RANKL treatment alone resulted in osteoclasts, whereas the addition of LPS/IFNγ to RANKL pre-treated macrophages generated Langhans-type giant cells, while IL-4 led to giant cells resembling foreign body giant cells with osteoclast-like characteristics. Finally, to gain insight into the modulation of osteoclastogenesis, we characterized the formation and morphology of RANKL and LPS/IFNγ-induced multinucleated giant cells.
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Affiliation(s)
- Sujeeve Jeganathan
- Ontario Cancer Institute and Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada
| | - Cara Fiorino
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
| | - Urja Naik
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
| | - He song Sun
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
| | - Rene E. Harrison
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
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19
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Biro M, Munoz MA, Weninger W. Targeting Rho-GTPases in immune cell migration and inflammation. Br J Pharmacol 2014; 171:5491-506. [PMID: 24571448 PMCID: PMC4282076 DOI: 10.1111/bph.12658] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 02/19/2014] [Accepted: 02/20/2014] [Indexed: 12/28/2022] Open
Abstract
Leukocytes are unmatched migrators capable of traversing barriers and tissues of remarkably varied structural composition. An effective immune response relies on the ability of its constituent cells to infiltrate target sites. Yet, unwarranted mobilization of immune cells can lead to inflammatory diseases and tissue damage ranging in severity from mild to life-threatening. The efficacy and plasticity of leukocyte migration is driven by the precise spatiotemporal regulation of the actin cytoskeleton. The small GTPases of the Rho family (Rho-GTPases), and their immediate downstream effector kinases, are key regulators of cellular actomyosin dynamics and are therefore considered prime pharmacological targets for stemming leukocyte motility in inflammatory disorders. This review describes advances in the development of small-molecule inhibitors aimed at modulating the Rho-GTPase-centric regulatory pathways governing motility, many of which stem from studies of cancer invasiveness. These inhibitors promise the advent of novel treatment options with high selectivity and potency against immune-mediated pathologies.
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Affiliation(s)
- Maté Biro
- Centenary Institute of Cancer Medicine and Cell Biology, Immune Imaging Program, Newtown, NSW, Australia; Sydney Medical School, The University of Sydney, Sydney, NSW, Australia
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20
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Olivares MJ, González-Jamett AM, Guerra MJ, Baez-Matus X, Haro-Acuña V, Martínez-Quiles N, Cárdenas AM. Src kinases regulate de novo actin polymerization during exocytosis in neuroendocrine chromaffin cells. PLoS One 2014; 9:e99001. [PMID: 24901433 PMCID: PMC4047038 DOI: 10.1371/journal.pone.0099001] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Accepted: 05/09/2014] [Indexed: 11/19/2022] Open
Abstract
The cortical actin network is dynamically rearranged during secretory processes. Nevertheless, it is unclear how de novo actin polymerization and the disruption of the preexisting actin network control transmitter release. Here we show that in bovine adrenal chromaffin cells, both formation of new actin filaments and disruption of the preexisting cortical actin network are induced by Ca2+ concentrations that trigger exocytosis. These two processes appear to regulate different stages of exocytosis; whereas the inhibition of actin polymerization with the N-WASP inhibitor wiskostatin restricts fusion pore expansion, thus limiting the release of transmitters, the disruption of the cortical actin network with cytochalasin D increases the amount of transmitter released per event. Further, the Src kinase inhibitor PP2, and cSrc SH2 and SH3 domains also suppress Ca2+-dependent actin polymerization, and slow down fusion pore expansion without disturbing the cortical F-actin organization. Finally, the isolated SH3 domain of c-Src prevents both the disruption of the actin network and the increase in the quantal release induced by cytochalasin D. These findings support a model where a rise in the cytosolic Ca2+ triggers actin polymerization through a mechanism that involves Src kinases. The newly formed actin filaments would speed up the expansion of the initial fusion pore, whereas the preexisting actin network might control a different step of the exocytosis process.
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Affiliation(s)
- María José Olivares
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Playa Ancha, Valparaíso, Chile
| | - Arlek M. González-Jamett
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Playa Ancha, Valparaíso, Chile
| | - María José Guerra
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Playa Ancha, Valparaíso, Chile
| | - Ximena Baez-Matus
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Playa Ancha, Valparaíso, Chile
| | - Valentina Haro-Acuña
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Playa Ancha, Valparaíso, Chile
| | - Narcisa Martínez-Quiles
- Departamento de Microbiología (Inmunología), Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain
| | - Ana M. Cárdenas
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Playa Ancha, Valparaíso, Chile
- * E-mail:
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21
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The F-BAR protein PSTPIP1 controls extracellular matrix degradation and filopodia formation in macrophages. Blood 2014; 123:2703-14. [PMID: 24421327 DOI: 10.1182/blood-2013-07-516948] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
PSTPIP1 is a cytoskeletal adaptor and F-BAR protein that has been implicated in autoinflammatory disease, most notably in the PAPA syndrome: pyogenic sterile arthritis, pyoderma gangrenosum, and acne. However, the mechanism by which PSTPIP1 regulates the actin cytoskeleton and contributes to disease pathogenesis remains elusive. Here, we show that endogenous PSTPIP1 negatively regulates macrophage podosome organization and matrix degradation. We identify a novel PSTPIP1-R405C mutation in a patient presenting with aggressive pyoderma gangrenosum. Identification of this mutation reveals that PSTPIP1 regulates the balance of podosomes and filopodia in macrophages. The PSTPIP1-R405C mutation is in the SRC homology 3 (SH3) domain and impairs Wiskott-Aldrich syndrome protein (WASP) binding, but it does not affect interaction with protein-tyrosine phosphatase (PTP)-PEST. Accordingly, WASP inhibition reverses the elevated F-actin content, filopodia formation, and matrix degradation induced by PSTPIP1-R405C. Our results uncover a novel role for PSTPIP1 and WASP in orchestrating different types of actin-based protrusions. Our findings implicate the cytoskeletal regulatory functions of PSTPIP1 in the pathogenesis of pyoderma gangrenosum and suggest that the cytoskeleton is a rational target for therapeutic intervention in autoinflammatory disease.
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Tsujita K, Kondo A, Kurisu S, Hasegawa J, Itoh T, Takenawa T. Antagonistic regulation of F-BAR protein assemblies controls actin polymerization during podosome formation. J Cell Sci 2013; 126:2267-78. [PMID: 23525018 DOI: 10.1242/jcs.122515] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
FBP17, an F-BAR domain protein, has emerged as a crucial factor linking the plasma membrane to WASP-mediated actin polymerization. Although it is well established that FBP17 has a powerful self-polymerizing ability that promotes actin nucleation on membranes in vitro, knowledge of inhibitory factors that counteract this activity in vivo is limited. Here, we demonstrate that the assembly of FBP17 on the plasma membranes is antagonized by PSTPIP2, another F-BAR protein implicated in auto-inflammatory disorder. Knockdown of PSTPIP2 in macrophage promotes the assembly of FBP17 as well as subsequent actin nucleation at podosomes, resulting in an enhancement of matrix degradation. This phenotype is rescued by expression of PSTPIP2 in a manner dependent on its F-BAR domain. Time-lapse total internal reflection fluorescence (TIRF) microscopy observations reveal that the self-assembly of FBP17 at the podosomal membrane initiates actin polymerization, whereas the clustering of PSTPIP2 has an opposite effect. Biochemical analysis and live-cell imaging show that PSTPIP2 inhibits actin polymerization by competing with FBP17 for assembly at artificial as well as the plasma membrane. Interestingly, the assembly of FBP17 is dependent on WASP, and its dissociation by WASP inhibition strongly induces a self-organization of PSTPIP2 at podosomes. Thus, our data uncover a previously unappreciated antagonism between different F-BAR domain assemblies that determines the threshold of actin polymerization for the formation of functional podosomes and may explain how the absence of PSTPIP2 causes auto-inflammatory disorder.
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Affiliation(s)
- Kazuya Tsujita
- Division of Lipid Biochemistry, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017, Japan
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23
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Guenin-Macé L, Veyron-Churlet R, Thoulouze MI, Romet-Lemonne G, Hong H, Leadlay PF, Danckaert A, Ruf MT, Mostowy S, Zurzolo C, Bousso P, Chrétien F, Carlier MF, Demangel C. Mycolactone activation of Wiskott-Aldrich syndrome proteins underpins Buruli ulcer formation. J Clin Invest 2013; 123:1501-12. [PMID: 23549080 DOI: 10.1172/jci66576] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Accepted: 01/29/2013] [Indexed: 12/30/2022] Open
Abstract
Mycolactone is a diffusible lipid secreted by the human pathogen Mycobacterium ulcerans, which induces the formation of open skin lesions referred to as Buruli ulcers. Here, we show that mycolactone operates by hijacking the Wiskott-Aldrich syndrome protein (WASP) family of actin-nucleating factors. By disrupting WASP autoinhibition, mycolactone leads to uncontrolled activation of ARP2/3-mediated assembly of actin in the cytoplasm. In epithelial cells, mycolactone-induced stimulation of ARP2/3 concentrated in the perinuclear region, resulting in defective cell adhesion and directional migration. In vivo injection of mycolactone into mouse ears consistently altered the junctional organization and stratification of keratinocytes, leading to epidermal thinning, followed by rupture. This degradation process was efficiently suppressed by coadministration of the N-WASP inhibitor wiskostatin. These results elucidate the molecular basis of mycolactone activity and provide a mechanism for Buruli ulcer pathogenesis. Our findings should allow for the rationale design of competitive inhibitors of mycolactone binding to N-WASP, with anti-Buruli ulcer therapeutic potential.
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Affiliation(s)
- Laure Guenin-Macé
- Institut Pasteur, Unité d'Immunobiologie de l'Infection, Paris, France
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Tanabe K, Ohashi E, Henmi Y, Takei K. Receptor sorting and actin dynamics at early endosomes. Commun Integr Biol 2012; 4:742-4. [PMID: 22446543 DOI: 10.4161/cib.17628] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The sorting machinery in early endosomes is crucial for intracellular homeostasis and signal transduction and its disruption leads to the development of various diseases. In spite of its significance, the molecular mechanism underlying this machinery remains largely unknown. Actin filaments are implicated in intracellular trafficking, including membrane fission at endocytosis, membrane stretching at the Golgi complex, and maturation of endosomes. We have recently found that actin is required for receptor sorting in early endosomes and identified cortactin as a candidate for actin regulation in early endosomes. Inhibition of actin dynamics leads to enlargement of early endosomes and impairment of the sorting; the latter is also observed in cortactin-depleted cells. The endosomal localization of cortactin was enhanced by dynasore, a dynamin inhibitor that effectively inhibits endosomal sorting, indicating that cortactin is involved in the sorting machinery in early endosomes. Here we discuss the role of actin filaments in early endosomes and other molecules implicated in endosomal trafficking.
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Affiliation(s)
- Kenji Tanabe
- Department of Neuroscience, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences; Okayama, Japan
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Claudin-5 is involved in breast cancer cell motility through the N-WASP and ROCK signalling pathways. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2012; 31:43. [PMID: 22559840 PMCID: PMC3432004 DOI: 10.1186/1756-9966-31-43] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Accepted: 02/18/2012] [Indexed: 01/02/2023]
Abstract
BACKGROUND Recent studies have shown dysregulation in TJ structure of several cancers including breast. Claudin-5 is a protein member of the TJ structure expressed in both endothelial and epithelial cells. This study examined the level of expression and distribution of Claudin-5 in human breast cancer tissues and the effect of knockdown and forced expression of Claudin-5 in the MDA-MB-231 breast cancer cell line. METHODS Immunohistochemistry and quantitative-PCR were used to analyse patient tissue samples. The Claudin-5 gene was cloned and overexpressed or knocked down using ribozyme technology in human breast cancer cells. Changes in function were assessed using in vitro assays for invasion, growth, adhesion, wounding, motility, transepithelial resistance and electric cell-substrate impedance sensing. Changes in cell behaviour were achieved through the use of Hepatocyte Growth factor (HGF) which we have shown to affect TJ function and expression of TJ proteins. In addition, an in vivo model was used for tumour growth assays. Results data was analyzed using a Students two sample t-test and by Two-way Anova test when the data was found to be normalized and have equal variances. In all cases 95% confidence intervals were used. RESULTS Patients whose tumours expressed high levels of Claudin-5 had shorter survival than those with low levels (p = 0.004). Investigating in vitro the effect of altering levels of expression of Claudin-5 in MDA-MB-231 cells revealed that the insertion of Claudin-5 gene resulted in significantly more motile cells (p < 0.005). Low levels of Claudin-5 resulted in a decrease in adhesion to matrix (p < 0.001). Furthermore, a possible link between Claudin-5 and N-WASP, and Claudin-5 and ROCK was demonstrated when interactions between these proteins were seen in the cells. Moreover, followed by treatment of N-WASP inhibitor (Wiskostatin) and ROCK inhibitor (Y-27632) cell motility was assessed in response to the inhibitors. Results showed that the knockdown of Claudin-5 in MDA-MB-231 masked their response after treatment with N-WASP inhibitor; however treatment with ROCK inhibitor did not reveal any differences in motility in this cell line. CONCLUSIONS This study portrays a very new and interesting role for Claudin-5 in cell motility involving the N-WASP signalling cascade indicating a possible role for Claudin-5 in the metastasis of human breast cancer.
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Impact of the carbazole derivative wiskostatin on mechanical stability and dynamics of motile cells. J Muscle Res Cell Motil 2012; 33:95-106. [PMID: 22407517 DOI: 10.1007/s10974-012-9287-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Accepted: 02/26/2012] [Indexed: 10/28/2022]
Abstract
Many essential functions in eukaryotic cells like phagocytosis, division, and motility rely on the dynamical properties of the actin cytoskeleton. A central player in the actin system is the Arp2/3 complex. Its activity is controlled by members of the WASP (Wiskott-Aldrich syndrome protein) family. In this work, we investigated the effect of the carbazole derivative wiskostatin, a recently identified N-WASP inhibitor, on actin-driven processes in motile cells of the social ameba Dictyostelium discoideum. Drug-treated cells exhibited an altered morphology and strongly reduced pseudopod formation. However, TIRF microscopy images revealed that the overall cortical network structure remained intact. We probed the mechanical stability of wiskostatin-treated cells using a microfluidic device. While the total amount of F-actin in the cells remained constant, their stiffness was strongly reduced. Furthermore, wiskostatin treatment enhanced the resistance to fluid shear stress, while spontaneous motility as well as chemotactic motion in gradients of cAMP were reduced. Our results suggest that wiskostatin affects the mechanical integrity of the actin cortex so that its rigidity is reduced and actin-driven force generation is impaired.
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Müller KH, Kakkola L, Nagaraj AS, Cheltsov AV, Anastasina M, Kainov DE. Emerging cellular targets for influenza antiviral agents. Trends Pharmacol Sci 2012; 33:89-99. [DOI: 10.1016/j.tips.2011.10.004] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Revised: 10/12/2011] [Accepted: 10/14/2011] [Indexed: 01/23/2023]
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Screening for small molecule inhibitors of embryonic pathways: sometimes you gotta crack a few eggs. Bioorg Med Chem 2011; 20:1869-77. [PMID: 22261025 DOI: 10.1016/j.bmc.2011.12.044] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Revised: 12/07/2011] [Accepted: 12/20/2011] [Indexed: 12/17/2022]
Abstract
Extract prepared from Xenopus eggs represents a cell-free system that has been shown to recapitulate a multitude of cellular processes, including cell cycle regulation, DNA replication/repair, and cytoskeletal dynamics. In addition, this system has been used to successfully reconstitute the Wnt pathway. Xenopus egg extract, which can be biochemically manipulated, offers an ideal medium in which small molecule screening can be performed in near native milieu. Thus, the use of Xenopus egg extract for small molecule screening represents an ideal bridge between targeted and phenotypic screening approaches. This review focuses on the use of this system for small molecules modulators of major signal transduction pathways (Notch, Hedgehog, and Wnt) that are critical for the development of the early Xenopus embryo. We describe the properties of Xenopus egg extract and our own high throughput screen for small molecules that modulate the Wnt pathway using this cell-free system. We propose that Xenopus egg extract could similarly be adapted for screening for modulators of the Notch and Hedgehog pathways.
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Karpushev AV, Levchenko V, Ilatovskaya DV, Pavlov TS, Staruschenko A. Novel role of Rac1/WAVE signaling mechanism in regulation of the epithelial Na+ channel. Hypertension 2011; 57:996-1002. [PMID: 21464391 DOI: 10.1161/hypertensionaha.110.157784] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The epithelial Na(+) channel (ENaC) is an essential channel responsible for Na(+) reabsorption in the aldosterone-sensitive distal nephron. Consequently, ENaC is a major effector impacting systemic blood volume and pressure. We have shown recently that Rac1 increases ENaC activity, whereas Cdc42 fails to change channel activity. Here we tested whether Rac1 signaling plays a physiological role in modulating ENaC in native tissue and polarized epithelial cells. We found that Rac1 inhibitor NSC23766 markedly decreased ENaC activity in freshly isolated collecting ducts. Knockdown of Rac1 in native principal cells decreased ENaC-mediated sodium reabsorption and the number of channels at the apical plasma membrane. Members of the Wiskott-Aldrich syndrome protein (WASP) family play a central role in the control of the actin cytoskeleton. N-WASP functions downstream of Cdc42, whereas WAVEs are effectors of Rac1 activity. N-WASP and all 3 isoforms of WAVE significantly increased ENaC activity when coexpressed in Chinese hamster ovary cells. However, wiskostatin, an inhibitor of N-WASP, had no effect on ENaC activity. Immunoblotting demonstrated the presence of WAVE1 and WAVE2 and absence of N-WASP and WAVE3 in mpkCCD(c14) and M-1 principal cells. Immunohistochemistry analysis also revealed localization of WAVE1 and WAVE2 but not N-WASP in the cortical collecting duct of Sprague-Dawley rat kidneys. Moreover, patch clamp analysis revealed that Rac1 and WAVE1/2 are parts of the same signaling pathway with respect to activation of ENaC. Thus, our findings suggest that Rac1 is essential for ENaC activity and regulates the channel via WAVE proteins.
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Affiliation(s)
- Alexey V Karpushev
- Department of Physiology, Medical College of Wisconsin, 8701 Watertown Plank Rd, Milwaukee, WI 53226, USA
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Fazlollahi F, Angelow S, Yacobi NR, Marchelletta R, Yu ASL, Hamm-Alvarez SF, Borok Z, Kim KJ, Crandall ED. Polystyrene nanoparticle trafficking across MDCK-II. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2011; 7:588-94. [PMID: 21310266 DOI: 10.1016/j.nano.2011.01.008] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2010] [Revised: 12/24/2010] [Accepted: 01/23/2011] [Indexed: 01/09/2023]
Abstract
Polystyrene nanoparticles (PNP) cross rat alveolar epithelial cell monolayers via non-endocytic transcellular pathways. To evaluate epithelial cell type-specificity of PNP trafficking, we studied PNP flux across Madin Darby canine kidney cell II monolayers (MDCK-II). The effects of calcium chelation (EGTA), energy depletion (sodium azide (NaN(3)) or decreased temperature), and endocytosis inhibitors methyl-β-cyclodextrin (MBC), monodansylcadaverine and dynasore were determined. Amidine-modified PNP cross MDCK-II 500 times faster than carboxylate-modified PNP. PNP flux did not increase in the presence of EGTA. PNP flux at 4 °C and after treatment with NaN(3) decreased 75% and 80%, respectively. MBC exposure did not decrease PNP flux, whereas dansylcadaverine- or dynasore-treated MDCK-II exhibited ∼80% decreases in PNP flux. Confocal laser scanning microscopy revealed intracellular colocalization of PNP with clathrin heavy chain. These data indicate that PNP translocation across MDCK-II (1) occurs via clathrin-mediated endocytosis and (2) is dependent on PNP physicochemical properties. We conclude that uptake/trafficking of nanoparticles (NPs) into/across epithelia depends both on properties of the NPs and on the specific epithelial cell type.
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Affiliation(s)
- Farnoosh Fazlollahi
- Will Rogers Institute Pulmonary Research Center, University of Southern California, Los Angeles, California 90033, USA.
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Carter GC, Bernstone L, Baskaran D, James W. HIV-1 infects macrophages by exploiting an endocytic route dependent on dynamin, Rac1 and Pak1. Virology 2011; 409:234-50. [DOI: 10.1016/j.virol.2010.10.018] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2010] [Revised: 10/04/2010] [Accepted: 10/13/2010] [Indexed: 01/12/2023]
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Montague P, Kennedy PGE, Barnett SC. Subcellular localization of Mayven following expression of wild type and mutant EGFP tagged cDNAs. BMC Neurosci 2010; 11:63. [PMID: 20504342 PMCID: PMC2901378 DOI: 10.1186/1471-2202-11-63] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2009] [Accepted: 05/26/2010] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Process formation by glial cells is crucial to their function. Mayven, an actin binding, multi-domain polypeptide, and member of the BTB-BACK-Kelch family have been shown to be important in oligodendrocyte process extension. To assess the role of Mayven in neural cell process extension we have tracked the subcellular distribution of exogenous Mayven following expression of a rat Mayven -EGFP cDNA in a variety of neural cell backgrounds and specifically in OEC tranfectants following drug treatment to disrupt the integrity of the cytoskeleton. A comparison was made between the subcellular localization following transient transfection of OECs with full-length Mayven cDNA and a series of mutant domain constructs. RESULTS The subcellular location of Mayven in OEC transfectants showed a characteristic distribution with intense foci of staining towards the process tips corresponding to regions of accumulated Mayven overlapping in part with lammelipodial actin and was absent from the filipodia and the outer membrane. This signature pattern was also observed in Schwann cells, Oli-Neu cells, astrocytes and the neuroblastoma cell line B104 transfectants and resembled the exogenous and endogenous Mayven distribution in oligodendrocytes. This contrasted with the localization pattern in non-neural cells. There was a re-localization of Mayven in OEC transfectants following drug treatment to challenge the integrity of the actin cytoskeleton while breakdown of the microtubular component had no discernible impact on the accumulation of Mayven in the process tips. Deletion of the first three amino acids of the SH3 motif of the putative Fyn Kinase binding domain at the amino terminus significantly compromised this signature pattern as did the removal of the last Kelch repeat unit of six unit Kelch domain comprising the carboxyl terminus. In addition, there was a reduction in process length in mutant transfectants. Co-expression studies with a haemagglutinin (HA) tagged wild type Mayven cDNA and EGFP tagged mutant cDNAs suggested a homomeric interaction mediated by the BTB/POZ domain. CONCLUSIONS Exogenous Mayven is transported to the lamellipodia in neural transfectants associating with the actin cytoskeletal network. In addition to the importance of the internal BTB/POZ domain, this subcellular distribution pattern is dependent on the presence of an intact amino and carboxyl terminus.
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Affiliation(s)
- Paul Montague
- Division of Clinical Neuroscience, Glasgow Biomedical Research Centre, Room 4B17, 120 University Place, University of Glasgow, Glasgow G12 8TA, UK
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Kellmann R, Schaffner CA, Grønset TA, Satake M, Ziegler M, Fladmark KE. Proteomic response of human neuroblastoma cells to azaspiracid-1. J Proteomics 2009; 72:695-707. [DOI: 10.1016/j.jprot.2009.02.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2008] [Revised: 02/11/2009] [Accepted: 02/16/2009] [Indexed: 12/25/2022]
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Bompard G, Rabeharivelo G, Morin N. Inhibition of cytokinesis by wiskostatin does not rely on N-WASP/Arp2/3 complex pathway. BMC Cell Biol 2008; 9:42. [PMID: 18667055 PMCID: PMC2527559 DOI: 10.1186/1471-2121-9-42] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2008] [Accepted: 07/30/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Cytokinesis is the final step of cell division taking place at the end of mitosis during which the cytoplasmic content and replicated chromosomes of a cell are equally partitioned between the two daughter cells. This process is achieved by the formation and the ingression of an actomyosin contractile ring under the control of equatorial microtubules. The mechanisms of contractile ring formation are not fully understood but involve recruitment of preexisting actin filaments and de novo actin polymerisation. RESULTS In this study, we evaluated the role of the actin nucleation factor, Arp2/3 complex, during cytokinesis. We found that the Arp2/3 complex is recruited late to the cleavage furrow suggesting a potential involvement of Arp2/3 complex during this process. Furthermore, wiskostatin a potent inhibitor of N-WASP activity towards the Arp2/3 complex blocked cytokinesis without affecting mitosis. Nonetheless, this inhibition could not be reproduced using alternative approaches targeting the N-WASP/Arp2/3 complex pathway. CONCLUSION We conclude that the wiskostatin induced defective cytokinesis does not occur through the inhibition of the N-WASP/Arp2/3 pathway. Wiskostatin is likely to either directly target other proteins required for cytokinesis progression or alternately wiskostatin bound to N-WASP could affect the activity of other factors involved in cytokinesis.
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Affiliation(s)
- Guillaume Bompard
- CRBM, CNRS UMR 5237, Université Montpellier I et II, 1919 route de Mende, 34293 Montpellier Cedex 5, France.
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Aga M, Bradley JM, Keller KE, Kelley MJ, Acott TS. Specialized podosome- or invadopodia-like structures (PILS) for focal trabecular meshwork extracellular matrix turnover. Invest Ophthalmol Vis Sci 2008; 49:5353-65. [PMID: 18641286 DOI: 10.1167/iovs.07-1666] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
PURPOSE There are distinctive areas of colocalization of matrix metalloproteinase (MMP)-2 and -14 on trabecular meshwork (TM) cells that resemble podosomes or invadopodia. Studies were conducted to determine whether TM cells exhibit podosome- or invadopodia-like structures (PILS) and whether they produce focal extracellular matrix (ECM) turnover. METHODS Porcine and human TM cells and perfused anterior segment organ cultures were studied. Localization of PILS components on TM cells and in sections from anterior segments was determined by immunohistochemistry and confocal microscopy. Cells were grown on type I collagen labeled with fluorescein isothiocyanate (FITC) for degradation analysis. Confocal time lapse images were taken of labeled TM cells on FITC-collagen. RESULTS Immunostaining for MMP-2, MMP-14, and the typical PILS components cortactin, caldesmon, alpha-actinin, N-WASP, Arp-3, and cdc42 colocalized on these distinctive structures. Integrin-alphaV and -beta1, fibronectin, and versican colocalized with PILS components. TM cells on FITC-conjugated collagen developed focal regions of degradation. Time-lapse imaging showed dramatic and controlled movement of TM cell processes during this ECM degradation and fragment internalization. MMP-2, MMP-14, and cortactin colocalized at regions that appear to be PILS on cells within the outflow pathway in sections of human anterior segments. CONCLUSIONS TM cells exhibit areas where PILS components colocalize with MMP-2 and -14. Similar structures are found in sections, suggesting that PILS occur in situ in the outflow pathway. The collagen degradation suggests that PILS may serve as focal sites for targeted ECM turnover, an event linked to modifications of aqueous outflow resistance and intraocular pressure homeostasis.
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Affiliation(s)
- Mini Aga
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon 97239-4197, USA
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Okiyoneda T, Lukacs GL. Cell surface dynamics of CFTR: the ins and outs. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2007; 1773:476-9. [PMID: 17306384 DOI: 10.1016/j.bbamcr.2007.01.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2006] [Revised: 01/04/2007] [Accepted: 01/10/2007] [Indexed: 11/18/2022]
Abstract
Ganeshan et al. (Biochem Biophys. Acta 1173 (2007) 192-200) recent study documents the effect of N-WASP inhibition and actin cytoskeleton disruption on the constitutive internalization and recycling of the cystic fibrosis transmembrane conductance regulator (CFTR) channel. The results implicate the cytoskeleton network as a potential modulator of immobilized CFTR pool size at the plasma membrane and the recycling efficiency of endocytosed channel back to the cell surface.
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Affiliation(s)
- Tsukasa Okiyoneda
- Hospital for Sick Children Research Institutes, Cell Biology, 555 University Av., Toronto, Ontario, Canada M5G 1X8
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Legg JA, Bompard G, Dawson J, Morris HL, Andrew N, Cooper L, Johnston SA, Tramountanis G, Machesky LM. N-WASP involvement in dorsal ruffle formation in mouse embryonic fibroblasts. Mol Biol Cell 2006; 18:678-87. [PMID: 17182853 PMCID: PMC1783773 DOI: 10.1091/mbc.e06-06-0569] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The Wiskott-Aldrich syndrome protein (WASP) family activates the Arp2/3 complex leading to the formation of new actin filaments. Here, we study the involvement of Scar1, Scar2, N-WASP, and Arp2/3 complex in dorsal ruffle formation in mouse embryonic fibroblasts (MEFs). Using platelet-derived growth factor to stimulate circular dorsal ruffle assembly in primary E13 and immortalized E9 Scar1(+/+) and Scar1 null MEFs, we establish that Scar1 loss does not impair the formation of dorsal ruffles. Reduction of Scar2 protein levels via small interfering RNA (siRNA) also did not affect dorsal ruffle production. In contrast, wiskostatin, a chemical inhibitor of N-WASP, potently suppressed dorsal ruffle formation in a dose-dependent manner. Furthermore, N-WASP and Arp2 siRNA treatment significantly decreased the formation of dorsal ruffles in MEFs. In addition, the expression of an N-WASP truncation mutant that cannot bind Arp2/3 complex blocked the formation of these structures. Finally, N-WASP(-/-) fibroblast-like cells generated aberrant dorsal ruffles. These ruffles were highly unstable, severely depleted of Arp2/3 complex, and diminished in size. We hypothesize that N-WASP and Arp2/3 complex are part of a multiprotein assembly important for the generation of dorsal ruffles and that Scar1 and Scar2 are dispensable for this process.
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Affiliation(s)
| | - Guillaume Bompard
- Centre de Recherches de Biochimie Macromoléculaire, Centre National de la Recherche Scientifique FRE2593, 34293 Montpellier, Cedex 5, France
| | | | | | | | - Lisa Cooper
- Medicine, The University of Birmingham, Birmingham, Edgbaston, West Midlands, B15 2TT, United Kingdom; and
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