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Wang Y, Wakelam MJO, Bankaitis VA, McDermott MI. The wide world of non-mammalian phospholipase D enzymes. Adv Biol Regul 2024; 91:101000. [PMID: 38081756 DOI: 10.1016/j.jbior.2023.101000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Accepted: 11/15/2023] [Indexed: 02/25/2024]
Abstract
Phospholipase D (PLD) hydrolyses phosphatidylcholine (PtdCho) to produce free choline and the critically important lipid signaling molecule phosphatidic acid (PtdOH). Since the initial discovery of PLD activities in plants and bacteria, PLDs have been identified in a diverse range of organisms spanning the taxa. While widespread interest in these proteins grew following the discovery of mammalian isoforms, research into the PLDs of non-mammalian organisms has revealed a fascinating array of functions ranging from roles in microbial pathogenesis, to the stress responses of plants and the developmental patterning of flies. Furthermore, studies in non-mammalian model systems have aided our understanding of the entire PLD superfamily, with translational relevance to human biology and health. Increasingly, the promise for utilization of non-mammalian PLDs in biotechnology is also being recognized, with widespread potential applications ranging from roles in lipid synthesis, to their exploitation for agricultural and pharmaceutical applications.
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Affiliation(s)
- Y Wang
- Department of Cell Biology & Genetics, Texas A&M Health Science Center, College Station, TX, 77843, USA; Department of Microbiology, University of Washington, Seattle, WA98109, USA
| | - M J O Wakelam
- Babraham Institute, Babraham Research Campus, Cambridge, CB22 3AT, United Kingdom
| | - V A Bankaitis
- Department of Cell Biology & Genetics, Texas A&M Health Science Center, College Station, TX, 77843, USA; Department of Biochemistry & Biophysics, Texas A&M University, College Station, TX, 77843, USA; Department of Chemistry, Texas A&M University, College Station, TX, 77843, USA
| | - M I McDermott
- Department of Cell Biology & Genetics, Texas A&M Health Science Center, College Station, TX, 77843, USA.
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2
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Auclair N, Sané AT, Delvin E, Spahis S, Levy E. Phospholipase D as a Potential Modulator of Metabolic Syndrome: Impact of Functional Foods. Antioxid Redox Signal 2021; 34:252-278. [PMID: 32586106 DOI: 10.1089/ars.2020.8081] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Significance: Cardiometabolic disorders (CMD) are composed of a plethora of metabolic dysfunctions such as dyslipidemia, nonalcoholic fatty liver disease, insulin resistance, and hypertension. The development of these disorders is highly linked to inflammation and oxidative stress (OxS), two metabolic states closely related to physiological and pathological conditions. Given the drastically rising CMD prevalence, the discovery of new therapeutic targets/novel nutritional approaches is of utmost importance. Recent Advances: The tremendous progress in methods/technologies and animal modeling has allowed the clarification of phospholipase D (PLD) critical roles in multiple cellular processes, whether directly or indirectly via phosphatidic acid, the lipid product mediating signaling functions. In view of its multiple features and implications in various diseases, PLD has emerged as a drug target. Critical Issues: Although insulin stimulates PLD activity and, in turn, PLD regulates insulin signaling, the impact of the two important PLD isoforms on the metabolic syndrome components remains vague. Therefore, after outlining PLD1/PLD2 characteristics and functions, their role in inflammation, OxS, and CMD has been analyzed and critically reported in the present exhaustive review. The influence of functional foods and nutrients in the regulation of PLD has also been examined. Future Directions: Available evidence supports the implication of PLD in CMD, but only few studies emphasize its mechanisms of action and specific regulation by nutraceutical compounds. Therefore, additional investigations are first needed to clarify the functional role of nutraceutics and, second, to elucidate whether targeting PLDs with food compounds represents an appropriate therapeutic strategy to treat CMD. Antioxid. Redox Signal. 34, 252-278.
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Affiliation(s)
- Nickolas Auclair
- Research Center, CHU Sainte-Justine, Université de Montréal, Montreal, Quebec, Canada.,Department of Pharmacology & Physiology and Université de Montréal, Montreal, Quebec, Canada
| | - Alain T Sané
- Research Center, CHU Sainte-Justine, Université de Montréal, Montreal, Quebec, Canada
| | - Edgard Delvin
- Research Center, CHU Sainte-Justine, Université de Montréal, Montreal, Quebec, Canada
| | - Schohraya Spahis
- Research Center, CHU Sainte-Justine, Université de Montréal, Montreal, Quebec, Canada.,Department of Nutrition, Université de Montréal, Montreal, Quebec, Canada
| | - Emile Levy
- Research Center, CHU Sainte-Justine, Université de Montréal, Montreal, Quebec, Canada.,Department of Pharmacology & Physiology and Université de Montréal, Montreal, Quebec, Canada.,Department of Nutrition, Université de Montréal, Montreal, Quebec, Canada
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3
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Guido I, Diehl D, Olszok NA, Bodenschatz E. Cellular velocity, electrical persistence and sensing in developed and vegetative cells during electrotaxis. PLoS One 2020; 15:e0239379. [PMID: 32946489 PMCID: PMC7500600 DOI: 10.1371/journal.pone.0239379] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 09/07/2020] [Indexed: 01/14/2023] Open
Abstract
Cells have the ability to detect electric fields and respond to them with directed migratory movement. Investigations identified genes and proteins that play important roles in defining the migration efficiency. Nevertheless, the sensing and transduction mechanisms underlying directed cell migration are still under discussion. We use Dictyostelium discoideum cells as model system for studying eukaryotic cell migration in DC electric fields. We have defined the temporal electric persistence to characterize the memory that cells have in a varying electric field. In addition to imposing a directional bias, we observed that the electric field influences the cellular kinematics by accelerating the movement of cells along their paths. Moreover, the study of vegetative and briefly starved cells provided insight into the electrical sensing of cells. We found evidence that conditioned medium of starved cells was able to trigger the electrical sensing of vegetative cells that would otherwise not orient themselves in the electric field. This observation may be explained by the presence of the conditioned medium factor (CMF), a protein secreted by the cells, when they begin to starve. The results of this study give new insights into understanding the mechanism that triggers the electrical sensing and transduces the external stimulus into directed cell migration. Finally, the observed increased mobility of cells over time in an electric field could offer a novel perspective towards wound healing assays.
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Affiliation(s)
- Isabella Guido
- Max-Planck Institute for Dynamics and Self-organization, Göttingen, Germany
- * E-mail:
| | - Douglas Diehl
- Max-Planck Institute for Dynamics and Self-organization, Göttingen, Germany
| | - Nora Aleida Olszok
- Max-Planck Institute for Dynamics and Self-organization, Göttingen, Germany
| | - Eberhard Bodenschatz
- Max-Planck Institute for Dynamics and Self-organization, Göttingen, Germany
- Institute for Dynamics of Complex Systems, Georg-August-University Göttingen, Göttingen, Germany
- Laboratory of Atomic and Solid-State Physics, Cornell University, Ithaca, NY, United States of America
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McDermott MI, Wang Y, Wakelam MJO, Bankaitis VA. Mammalian phospholipase D: Function, and therapeutics. Prog Lipid Res 2019; 78:101018. [PMID: 31830503 DOI: 10.1016/j.plipres.2019.101018] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 10/08/2019] [Accepted: 10/14/2019] [Indexed: 01/23/2023]
Abstract
Despite being discovered over 60 years ago, the precise role of phospholipase D (PLD) is still being elucidated. PLD enzymes catalyze the hydrolysis of the phosphodiester bond of glycerophospholipids producing phosphatidic acid and the free headgroup. PLD family members are found in organisms ranging from viruses, and bacteria to plants, and mammals. They display a range of substrate specificities, are regulated by a diverse range of molecules, and have been implicated in a broad range of cellular processes including receptor signaling, cytoskeletal regulation and membrane trafficking. Recent technological advances including: the development of PLD knockout mice, isoform-specific antibodies, and specific inhibitors are finally permitting a thorough analysis of the in vivo role of mammalian PLDs. These studies are facilitating increased recognition of PLD's role in disease states including cancers and Alzheimer's disease, offering potential as a target for therapeutic intervention.
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Affiliation(s)
- M I McDermott
- Department of Molecular and Cellular Medicine, Texas A&M Health Science Center, College Station, TX 77843-1114, United States of America.
| | - Y Wang
- Department of Molecular and Cellular Medicine, Texas A&M Health Science Center, College Station, TX 77843-1114, United States of America; Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843-2128, United States of America
| | - M J O Wakelam
- Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, United Kingdom
| | - V A Bankaitis
- Department of Molecular and Cellular Medicine, Texas A&M Health Science Center, College Station, TX 77843-1114, United States of America; Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843-2128, United States of America; Department of Chemistry, Texas A&M University, College Station, Texas 77840, United States of America
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5
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Singh S, Mohamed W, Aguessy A, Dyett E, Shah S, Khan M, Baskar R, Brazill D. Functional interaction of PkcA and PldB regulate aggregation and development in Dictyostelium discoideum. Cell Signal 2017; 34:47-54. [PMID: 28257811 DOI: 10.1016/j.cellsig.2017.02.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 02/24/2017] [Accepted: 02/24/2017] [Indexed: 10/20/2022]
Abstract
Multicellular development in Dictyostelium discoideum involves tightly regulated signaling events controlling the entry into development, initiation of aggregation and chemotaxis, and cellular differentiation. Here we show that PkcA, a Dictyostelium discoideum Protein Kinase C-orthologue, is involved in quorum sensing and the initiation of development, as well as cAMP sensing during chemotaxis. Additionally, by epistasis analysis we provide evidence that PkcA and PldB (a Phospholipase D-orthologue) functionally interact to regulate aggregation, differentiation, and cell-cell adhesion during development. Finally, we show that PkcA acts as a positive regulator of intracellular PLD-activity during development. Taken together, our results suggest that PkcA act through PldB, by regulating PLD-activity, in order to control events during development.
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Affiliation(s)
- Sean Singh
- Department of Biological Sciences, Hunter College and The Graduate Center, The City University of New York, New York, NY, USA
| | - Wasima Mohamed
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology-Madras, Chennai 600036, India
| | - Annelie Aguessy
- Department of Biological Sciences, Hunter College and The Graduate Center, The City University of New York, New York, NY, USA
| | - Ella Dyett
- Department of Biological Sciences, Hunter College and The Graduate Center, The City University of New York, New York, NY, USA
| | - Shriraj Shah
- Department of Biological Sciences, Hunter College and The Graduate Center, The City University of New York, New York, NY, USA
| | - Mohammedasad Khan
- Department of Biological Sciences, Hunter College and The Graduate Center, The City University of New York, New York, NY, USA
| | - Ramamurthy Baskar
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology-Madras, Chennai 600036, India
| | - Derrick Brazill
- Department of Biological Sciences, Hunter College and The Graduate Center, The City University of New York, New York, NY, USA.
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6
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Determination of cell uptake pathways for tumor inhibitor lysyl oxidase propeptide. Mol Oncol 2015; 10:1-23. [PMID: 26297052 DOI: 10.1016/j.molonc.2015.07.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2015] [Revised: 07/24/2015] [Accepted: 07/27/2015] [Indexed: 01/13/2023] Open
Abstract
The lysyl oxidase propeptide (LOX-PP) is derived from pro-lysyl oxidase (Pro-LOX) by extracellular biosynthetic proteolysis. LOX-PP inhibits breast and prostate cancer xenograft tumor growth and has tumor suppressor activity. Although, several intracellular targets and molecular mechanisms of action of LOX-PP have been identified, LOX-PP uptake pathways have not been reported. Here we demonstrate that the major uptake pathway for recombinant LOX-PP (rLOX-PP) is PI3K-dependent macropinocytosis in PWR-1E, PC3, SCC9, MDA-MB-231 cell lines. A secondary pathway appears to be dynamin- and caveola dependent. The ionic properties of highly basic rLOX-PP provide buffering capacity at both high and low pHs. We suggest that the buffering capacity of rLOX-PP, which serves to limit endosomal acidification, sustains PI3K-dependent macropinocytosis in endosomes which in turn is likely to facilitate LOX-PP endosomal escape into the cytoplasm and its observed interactions with cytoplasmic targets and nuclear uptake.
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7
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Speranza F, Mahankali M, Henkels KM, Gomez-Cambronero J. The molecular basis of leukocyte adhesion involving phosphatidic acid and phospholipase D. J Biol Chem 2014; 289:28885-97. [PMID: 25187519 DOI: 10.1074/jbc.m114.597146] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Defining how leukocytes adhere to solid surfaces, such as capillary beds, and the subsequent migration through the extracellular matrix, is a central biological issue. We show here that phospholipase D (PLD) and its enzymatic reaction product, phosphatidic acid (PA), regulate cell adhesion of immune cells (macrophages and neutrophils) to collagen and have defined the underlying molecular mechanism in a spatio-temporal manner that coincides with PLD activity timing. A rapid (t½ = 4 min) and transient activation of the PLD1 isoform occurs upon adhesion, and a slower (t½ = 7.5 min) but prolonged (>30 min) activation occurs for PLD2. Importantly, PA directly binds to actin-related protein 3 (Arp3) at EC50 = 22 nm, whereas control phosphatidylcholine did not bind. PA-activated Arp3 hastens actin nucleation with a kinetics of t½ = 3 min at 300 nm (compared with controls of no PA, t½ = 5 min). Thus, PLD and PA are intrinsic components of cell adhesion, which reinforce each other in a positive feedback loop and react from cues from their respective solid substrates. In nascent adhesion, PLD1 is key, whereas a sustained adhesion in mature or established focal points is dependent upon PLD2, PA, and Arp3. A prolonged adhesion could effectively counteract the reversible intrinsic nature of this cellular process and constitute a key player in chronic inflammation.
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Affiliation(s)
- Francis Speranza
- From the Department of Biochemistry and Molecular Biology, Wright State University School of Medicine, Dayton, Ohio 45435
| | - Madhu Mahankali
- From the Department of Biochemistry and Molecular Biology, Wright State University School of Medicine, Dayton, Ohio 45435
| | - Karen M Henkels
- From the Department of Biochemistry and Molecular Biology, Wright State University School of Medicine, Dayton, Ohio 45435
| | - Julian Gomez-Cambronero
- From the Department of Biochemistry and Molecular Biology, Wright State University School of Medicine, Dayton, Ohio 45435
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8
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Gomez-Cambronero J. Phospholipase D in cell signaling: from a myriad of cell functions to cancer growth and metastasis. J Biol Chem 2014; 289:22557-22566. [PMID: 24990944 PMCID: PMC4132763 DOI: 10.1074/jbc.r114.574152] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Phospholipase D (PLD) enzymes play a double vital role in cells: they maintain the integrity of cellular membranes and they participate in cell signaling including intracellular protein trafficking, cytoskeletal dynamics, cell migration, and cell proliferation. The particular involvement of PLD in cell migration is accomplished: (a) through the actions of its enzymatic product of reaction, phosphatidic acid, and its unique shape-binding role on membrane geometry; (b) through a particular guanine nucleotide exchange factor (GEF) activity (the first of its class assigned to a phospholipase) in the case of the mammalian isoform PLD2; and (c) through protein-protein interactions with a wide network of molecules: Wiskott-Aldrich syndrome protein (WASp), Grb2, ribosomal S6 kinase (S6K), and Rac2. Further, PLD interacts with a variety of kinases (PKC, FES, EGF receptor (EGFR), and JAK3) that are activated by it, or PLD becomes the target substrate. Out of these myriads of functions, PLD is becoming recognized as a major player in cell migration, cell invasion, and cancer metastasis. This is the story of the evolution of PLD from being involved in a large number of seemingly unrelated cellular functions to its most recent role in cancer signaling, a subfield that is expected to grow exponentially.
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Affiliation(s)
- Julian Gomez-Cambronero
- Department of Biochemistry and Molecular Biology, Boonshoft School of Medicine, Wright State University School of Medicine, Dayton, Ohio 45435.
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9
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Calabrese B, Saffin JM, Halpain S. Activity-dependent dendritic spine shrinkage and growth involve downregulation of cofilin via distinct mechanisms. PLoS One 2014; 9:e94787. [PMID: 24740405 PMCID: PMC3989342 DOI: 10.1371/journal.pone.0094787] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Accepted: 03/19/2014] [Indexed: 01/09/2023] Open
Abstract
A current model posits that cofilin-dependent actin severing negatively impacts dendritic spine volume. Studies suggested that increased cofilin activity underlies activity-dependent spine shrinkage, and that reduced cofilin activity induces activity-dependent spine growth. We suggest instead that both types of structural plasticity correlate with decreased cofilin activity. However, the mechanism of inhibition determines the outcome for spine morphology. RNAi in rat hippocampal cultures demonstrates that cofilin is essential for normal spine maintenance. Cofilin-F-actin binding and filament barbed-end production decrease during the early phase of activity-dependent spine shrinkage; cofilin concentration also decreases. Inhibition of the cathepsin B/L family of proteases prevents both cofilin loss and spine shrinkage. Conversely, during activity-dependent spine growth, LIM kinase stimulates cofilin phosphorylation, which activates phospholipase D-1 to promote actin polymerization. These results implicate novel molecular mechanisms and prompt a revision of the current model for how cofilin functions in activity-dependent structural plasticity.
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Affiliation(s)
- Barbara Calabrese
- Division of Biological Sciences, and Sanford Consortium for Regenerative Medicine, University of California San Diego, La Jolla, California, United States of America
| | - Jean-Michel Saffin
- Division of Biological Sciences, and Sanford Consortium for Regenerative Medicine, University of California San Diego, La Jolla, California, United States of America
| | - Shelley Halpain
- Division of Biological Sciences, and Sanford Consortium for Regenerative Medicine, University of California San Diego, La Jolla, California, United States of America
- * E-mail:
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10
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Dallaire-Dufresne S, Barbeau X, Sarty D, Tanaka KH, Denoncourt AM, Lagüe P, Reith ME, Charette SJ. Aeromonas salmonicida Ati2 is an effector protein of the type three secretion system. Microbiology (Reading) 2013; 159:1937-1945. [DOI: 10.1099/mic.0.067959-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Affiliation(s)
- Stéphanie Dallaire-Dufresne
- Centre de recherche de l’Institut universitaire de cardiologie et de pneumologie de Québec, Quebec City, Quebec G1V 4G5, Canada
- Département de biochimie, de microbiologie et de bio-informatique, Faculté des sciences et de génie, Université Laval, Quebec City, Quebec G1V 0A6, Canada
- Institut de biologie intégrative et des systèmes, Faculté des sciences et de génie, Université Laval, Quebec City, Quebec G1V 0A6, Canada
| | - Xavier Barbeau
- Département de biochimie, de microbiologie et de bio-informatique, Faculté des sciences et de génie, Université Laval, Quebec City, Quebec G1V 0A6, Canada
- Institut de biologie intégrative et des systèmes, Faculté des sciences et de génie, Université Laval, Quebec City, Quebec G1V 0A6, Canada
| | - Darren Sarty
- Aquatic and Crop Resource Development, National Research Council Canada, Halifax, Nova Scotia B3H 3Z1, Canada
| | - Katherine H. Tanaka
- Centre de recherche de l’Institut universitaire de cardiologie et de pneumologie de Québec, Quebec City, Quebec G1V 4G5, Canada
- Département de biochimie, de microbiologie et de bio-informatique, Faculté des sciences et de génie, Université Laval, Quebec City, Quebec G1V 0A6, Canada
- Institut de biologie intégrative et des systèmes, Faculté des sciences et de génie, Université Laval, Quebec City, Quebec G1V 0A6, Canada
| | - Alix M. Denoncourt
- Centre de recherche de l’Institut universitaire de cardiologie et de pneumologie de Québec, Quebec City, Quebec G1V 4G5, Canada
- Département de biochimie, de microbiologie et de bio-informatique, Faculté des sciences et de génie, Université Laval, Quebec City, Quebec G1V 0A6, Canada
- Institut de biologie intégrative et des systèmes, Faculté des sciences et de génie, Université Laval, Quebec City, Quebec G1V 0A6, Canada
| | - Patrick Lagüe
- Département de biochimie, de microbiologie et de bio-informatique, Faculté des sciences et de génie, Université Laval, Quebec City, Quebec G1V 0A6, Canada
- Institut de biologie intégrative et des systèmes, Faculté des sciences et de génie, Université Laval, Quebec City, Quebec G1V 0A6, Canada
| | - Michael E. Reith
- Aquatic and Crop Resource Development, National Research Council Canada, Halifax, Nova Scotia B3H 3Z1, Canada
| | - Steve J. Charette
- Centre de recherche de l’Institut universitaire de cardiologie et de pneumologie de Québec, Quebec City, Quebec G1V 4G5, Canada
- Département de biochimie, de microbiologie et de bio-informatique, Faculté des sciences et de génie, Université Laval, Quebec City, Quebec G1V 0A6, Canada
- Institut de biologie intégrative et des systèmes, Faculté des sciences et de génie, Université Laval, Quebec City, Quebec G1V 0A6, Canada
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Phospholipase D (PLD) drives cell invasion, tumor growth and metastasis in a human breast cancer xenograph model. Oncogene 2013; 32:5551-62. [PMID: 23752189 PMCID: PMC3966651 DOI: 10.1038/onc.2013.207] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Revised: 04/18/2013] [Accepted: 04/21/2013] [Indexed: 12/19/2022]
Abstract
Breast cancer is one of the most common malignancies in human females in the world. One protein that has elevated enzymatic lipase activity in breast cancers in vitro is phospholipase D (PLD), which is also involved in cell migration. We demonstrate that the PLD2 isoform, which was analyzed directly in the tumors, is crucial for cell invasion that contributes critically to the growth and development of breast tumors and lung metastases in vivo. We used three complementary strategies in a SCID mouse model and also addressed the underlying molecular mechanism. First, the PLD2 gene was silenced in highly metastatic, aggressive breast cancer cells (MDA-MB-231) with lentivirus-based shRNA, which were xenotransplanted in SCID mice. The resulting mouse primary mammary tumors were reduced in size (65%, p<0.05) and their onset delayed when compared to control tumors. Second, we stably overexpressed PLD2 in low-invasive breast cancer cells (MCF-7) with a biscistronic MIEG retroviral vector and observed that these cells were converted into a highly aggressive phenotype, as primary tumors that formed following xenotransplantation were larger, grew faster and developed lung metastases more readily. Third, we implanted osmotic pumps into SCID xenotransplanted mice that delivered two different small-molecule inhibitors of PLD activity (FIPI and NOPT). These inhibitors led to significant (>70%, p<0.05) inhibition of primary tumor growth, metastatic axillary tumors and lung metastases. In order to define the underlying mechanism, we determined that the machinery of PLD-induced cell invasion is mediated by phosphatidic acid (PA), WASp, Grb2 and Rac2 signaling events that ultimately affect actin polymerization and cell invasion. In summary, this study shows that PLD has a central role in the development, metastasis and level of aggressiveness of breast cancer, raising the possibility that PLD2 could be used as a new therapeutic target.
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Williams JT, Ingram SL, Henderson G, Chavkin C, von Zastrow M, Schulz S, Koch T, Evans CJ, Christie MJ. Regulation of μ-opioid receptors: desensitization, phosphorylation, internalization, and tolerance. Pharmacol Rev 2013; 65:223-54. [PMID: 23321159 DOI: 10.1124/pr.112.005942] [Citation(s) in RCA: 585] [Impact Index Per Article: 53.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Morphine and related µ-opioid receptor (MOR) agonists remain among the most effective drugs known for acute relief of severe pain. A major problem in treating painful conditions is that tolerance limits the long-term utility of opioid agonists. Considerable effort has been expended on developing an understanding of the molecular and cellular processes that underlie acute MOR signaling, short-term receptor regulation, and the progression of events that lead to tolerance for different MOR agonists. Although great progress has been made in the past decade, many points of contention and controversy cloud the realization of this progress. This review attempts to clarify some confusion by clearly defining terms, such as desensitization and tolerance, and addressing optimal pharmacological analyses for discerning relative importance of these cellular mechanisms. Cellular and molecular mechanisms regulating MOR function by phosphorylation relative to receptor desensitization and endocytosis are comprehensively reviewed, with an emphasis on agonist-biased regulation and areas where knowledge is lacking or controversial. The implications of these mechanisms for understanding the substantial contribution of MOR signaling to opioid tolerance are then considered in detail. While some functional MOR regulatory mechanisms contributing to tolerance are clearly understood, there are large gaps in understanding the molecular processes responsible for loss of MOR function after chronic exposure to opioids. Further elucidation of the cellular mechanisms that are regulated by opioids will be necessary for the successful development of MOR-based approaches to new pain therapeutics that limit the development of tolerance.
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Affiliation(s)
- John T Williams
- Vollum Institute, Oregon Health Sciences University, Portland, Oregon, USA
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Poloz Y, O'Day DH. Colchicine affects cell motility, pattern formation and stalk cell differentiation in Dictyostelium by altering calcium signaling. Differentiation 2012; 83:185-99. [PMID: 22381626 DOI: 10.1016/j.diff.2011.12.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Revised: 12/05/2011] [Accepted: 12/23/2011] [Indexed: 11/26/2022]
Abstract
Previous work, verified here, showed that colchicine affects Dictyostelium pattern formation, disrupts morphogenesis, inhibits spore differentiation and induces terminal stalk cell differentiation. Here we show that colchicine specifically induces ecmB expression and enhances accumulation of ecmB-expressing cells at the posterior end of multicellular structures. Colchicine did not induce a nuclear translocation of DimB, a DIF-1 responsive transcription factor in vitro. It also induced terminal stalk cell differentiation in a mutant strain that does not produce DIF-1 (dmtA-) and after the treatment of cells with DIF-1 synthesis inhibitor cerulenin (100 μM). This suggests that colchicine induces the differentiation of ecmB-expressing cells independent of DIF-1 production and likely through a signaling pathway that is distinct from the one that is utilized by DIF-1. Depending on concentration, colchicine enhanced random cell motility, but not chemotaxis, by 3-5 fold (10-50 mM colchicine, respectively) through a Ca(2+)-mediated signaling pathway involving phospholipase C, calmodulin and heterotrimeric G proteins. Colchicine's effects were not due to microtubule depolymerization as other microtubule-depolymerizing agents did not have these effects. Finally normal morphogenesis and stalk and spore cell differentiation of cells treated with 10 mM colchicine were rescued through chelation of Ca2+ by BAPTA-AM and EDTA and calmodulin antagonism by W-7 but not PLC inhibition by U-73122. Morphogenesis or spore cell differentiation of cells treated with 50 mM colchicine could not be rescued by the above treatments but terminal stalk cell differentiation was inhibited by BAPTA-AM, EDTA and W-7, but not U-73122. Thus colchicine disrupts morphogenesis and induces stalk cell differentiation through a Ca(2+)-mediated signaling pathway involving specific changes in gene expression and cell motility.
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Affiliation(s)
- Yekaterina Poloz
- Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, Ontario, Canada M5S 3G5.
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14
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Abstract
Phosphatidylinositol lipids generated through the action of phosphinositide 3-kinase (PI3K) are key mediators of a wide array of biological responses. In particular, their role in the regulation of cell migration has been extensively studied and extends to amoeboid as well as mesenchymal migration. Through the emergence of fluorescent probes that target PI3K products as well as the use of specific inhibitors and knockout technologies, the spatio-temporal distribution of PI3K products in chemotaxing cells has been shown to represent a key anterior polarity signal that targets downstream effectors to actin polymerization. In addition, through intricate cross-talk networks PI3K products have been shown to regulate signals that control posterior effectors. Yet, in more complex environments or in conditions where chemoattractant gradients are steep, a variety of cell types can still chemotax in the absence of PI3K signals. Indeed, parallel signal transduction pathways have been shown to coordinately regulate cell polarity and directed movement. In this chapter, we will review the current role PI3K products play in the regulation of directed cell migration in various cell types, highlight the importance of mathematical modeling in the study of chemotaxis, and end with a brief overview of other signaling cascades known to also regulate chemotaxis.
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Affiliation(s)
- Michael C Weiger
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, National Institutes of Health, 37 Convent Drive, Bldg.37/Rm2066, 20892-4256, Bethesda, MD, USA
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15
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Itach SBS, Finklestein M, Etkovitz N, Breitbart H. Hyper-activated motility in sperm capacitation is mediated by phospholipase D-dependent actin polymerization. Dev Biol 2011; 362:154-61. [PMID: 22178154 DOI: 10.1016/j.ydbio.2011.12.002] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2011] [Revised: 11/22/2011] [Accepted: 12/01/2011] [Indexed: 12/15/2022]
Abstract
In order to fertilize the oocyte, sperm must undergo a series of biochemical changes in the female reproductive tract, known as capacitation. Once capacitated, spermatozoon can bind to the zona pellucida of the egg and undergo the acrosome reaction (AR), a process that enables its penetration and fertilization of the oocyte. Important processes that characterize sperm capacitation are actin polymerization and the development of hyper-activated motility (HAM). Previously, we showed that Phospholipase D (PLD)-dependent actin polymerization occurs during sperm capacitation, however the role of this process in sperm capacitation is not yet known. In the present study, we showed for the first time the involvement of PLD-dependent actin polymerization in sperm motility during mouse and human capacitation. Sperm incubated under capacitation conditions revealed a time dependent increase in actin polymerization and HAM. Inhibition of Phosphatidic Acid (PA) formation by PLD using butan-1-ol, inhibited actin polymerization and motility, as well as in vitro fertilization (IVF) and the ability of the sperm to undergo the AR. The inhibition of sperm HAM by low concentration of butan-1-ol is completely restored by adding PA, further indicating the involvement of PLD in these processes. Furthermore, exogenous PA enhanced rapid actin polymerization that was followed by a rise in the HAM, as well as an increased in IVF rate. In conclusion, our results demonstrate that PLD-dependent actin polymerization is a critical step needed for the development of HAM during mouse and human sperm capacitation.
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Affiliation(s)
- Sarit Bar-Sheshet Itach
- The Mina & Everard Goodman Faculty of Life Sciences, Bar-Ilan University Ramat-Gan, 52900, Israel
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16
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Gomez-Cambronero J. The exquisite regulation of PLD2 by a wealth of interacting proteins: S6K, Grb2, Sos, WASp and Rac2 (and a surprise discovery: PLD2 is a GEF). Cell Signal 2011; 23:1885-95. [PMID: 21740967 PMCID: PMC3204931 DOI: 10.1016/j.cellsig.2011.06.017] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Accepted: 06/21/2011] [Indexed: 11/28/2022]
Abstract
Phospholipase D (PLD) catalyzes the conversion of the membrane phospholipid phosphatidylcholine to choline and phosphatidic acid (PA). PLD's mission in the cell is two-fold: phospholipid turnover with maintenance of the structural integrity of cellular/intracellular membranes and cell signaling through PA and its metabolites. Precisely, through its product of the reaction, PA, PLD has been implicated in a variety of physiological cellular functions, such as intracellular protein trafficking, cytoskeletal dynamics, chemotaxis of leukocytes and cell proliferation. The catalytic (HKD) and regulatory (PH and PX) domains were studied in detail in the PLD1 isoform, but PLD2 was traditionally studied in lesser detail and much less was known about its regulation. Our laboratory has been focusing on the study of PLD2 regulation in mammalian cells. Over the past few years, we have reported, in regards to the catalytic action of PLD, that PA is a chemoattractant agent that binds to and signals inside the cell through the ribosomal S6 kinases (S6K). Regarding the regulatory domains of PLD2, we have reported the discovery of the PLD2 interaction with Grb2 via Y169 in the PX domain, and further association to Sos, which results in an increase of de novo DNA synthesis and an interaction (also with Grb2) via the adjacent residue Y179, leading to the regulation of cell ruffling, chemotaxis and phagocytosis of leukocytes. We also present the complex regulation by tyrosine phosphorylation by epidermal growth factor receptor (EGF-R), Janus Kinase 3 (JAK3) and Src and the role of phosphatases. Recently, there is evidence supporting a new level of regulation of PLD2 at the PH domain, by the discovery of CRIB domains and a Rac2-PLD2 interaction that leads to a dual (positive and negative) effect on its enzymatic activity. Lastly, we review the surprising finding of PLD2 acting as a GEF. A phospholipase such as PLD that exists already in the cell membrane that acts directly on Rac allows a quick response of the cell without intermediary signaling molecules. This provides only the latest level of PLD2 regulation in a field that promises newer and exciting advances in the next few years.
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Affiliation(s)
- Julian Gomez-Cambronero
- Department of Biochemistry and Molecular Biology, Wright State University School of Medicine, Dayton, OH 45435, USA.
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17
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Selvy PE, Lavieri RR, Lindsley CW, Brown HA. Phospholipase D: enzymology, functionality, and chemical modulation. Chem Rev 2011; 111:6064-119. [PMID: 21936578 PMCID: PMC3233269 DOI: 10.1021/cr200296t] [Citation(s) in RCA: 267] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Paige E Selvy
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee 37064, USA
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18
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Norton LJ, Zhang Q, Saqib KM, Schrewe H, Macura K, Anderson KE, Lindsley CW, Brown HA, Rudge SA, Wakelam MJO. PLD1 rather than PLD2 regulates phorbol-ester-, adhesion-dependent and Fc{gamma}-receptor-stimulated ROS production in neutrophils. J Cell Sci 2011; 124:1973-83. [PMID: 21610093 DOI: 10.1242/jcs.082008] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The signalling lipid phosphatidic acid (PA) is generated by the hydrolysis of phosphatidylcholine (PC), which is catalysed by phospholipase D (PLD) enzymes. Neutrophils, important cells of the innate immune system, maintain the body's defence against infection. Previous studies have implicated PLD-generated PA in neutrophil function; these have relied heavily on the use of primary alcohols to act as inhibitors of PA production. The recent development of isoform-selective small molecule inhibitors and the generation of a knockout mouse model provide us with accurate tools to study the role of PLDs in neutrophil responses. We show that PLD1 is a regulator of phorbol-ester-, chemoattractant, adhesion-dependent and Fcγ-receptor-stimulated production of reactive oxygen species (ROS) in neutrophils. Significantly we found that this role of PLD is isoform specific: the absence of PLD2 does not negatively affect these processes. Contrary to expectation, other functions required for an efficient immune response operate effectively in Pld2-deficient neutrophils or when both isoforms are inhibited pharmacologically. We conclude that although PLD1 does have important regulatory roles in neutrophils, the field has been confused by the use of primary alcohols; now that gold standard Pld-knockout mouse models are available, previous work might need to be reassessed.
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Affiliation(s)
- Laura J Norton
- The Inositide Laboratory, The Babraham Institute, Babraham, Cambridge CB223AT, UK
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19
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Paxillin and phospholipase D interact to regulate actin-based processes in Dictyostelium discoideum. EUKARYOTIC CELL 2011; 10:977-84. [PMID: 21531871 DOI: 10.1128/ec.00282-10] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The actin cytoskeleton forms a membrane-associated network whose proper regulation is essential for numerous processes, including cell differentiation, proliferation, adhesion, chemotaxis, endocytosis, exocytosis, and multicellular development. In this report, we show that in Dictyostelium discoideum, paxillin (PaxB) and phospholipase D (PldB) colocalize and coimmunoprecipitate, suggesting that they interact physically. Additionally, the phenotypes observed during development, cell sorting, and several actin-required processes, including cyclic AMP (cAMP) chemotaxis, cell-substrate adhesion, actin polymerization, phagocytosis, and exocytosis, reveal a genetic interaction between paxB and pldB, suggesting a functional interaction between their gene products. Taken together, our data point to PldB being a required binding partner of PaxB during processes involving actin reorganization.
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20
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Abstract
The social amoeba Dictyostelium discoideum is one of the leading model systems used to study how cells count themselves to determine the number and/or density of cells. In this review, we describe work on three different cell-density sensing systems used by Dictyostelium. The first involves a negative feedback loop in which two secreted signals inhibit cell proliferation during the growth phase. As the cell density increases, the concentrations of the secreted factors concomitantly increase, allowing the cells to sense their density. The two signals act as message authenticators for each other, and the existence of two different signals that require each other for activity may explain why previous efforts to identify autocrine proliferation-inhibiting signals in higher eukaryotes have generally failed. The second system involves a signal made by growing cells that is secreted only when they starve. This then allows cells to sense the density of just the starving cells, and is an example of a mechanism that allows cells in a tissue to sense the density of one specific cell type. The third cell density counting system involves cells in aggregation streams secreting a signal that limits the size of fruiting bodies. Computer simulations predicted, and experiments then showed, that the factor increases random cell motility and decreases cell-cell adhesion to cause streams to break up if there are too many cells in the stream. Together, studies on Dictyostelium cell density counting systems will help elucidate how higher eukaryotes regulate the size and composition of tissues.
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Affiliation(s)
- Richard H Gomer
- Department of Biology, ILSB MS 3474, Texas A&M University, College Station, Texas 77843-3474, USA.
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21
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Ray S, Chen Y, Ayoung J, Hanna R, Brazill D. Phospholipase D controls Dictyostelium development by regulating G protein signaling. Cell Signal 2010; 23:335-43. [PMID: 20950684 DOI: 10.1016/j.cellsig.2010.09.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2010] [Revised: 09/21/2010] [Accepted: 09/28/2010] [Indexed: 10/19/2022]
Abstract
Dictyostelium discoideum cells normally exist as individual amoebae, but will enter a period of multicellular development upon starvation. The initial stages of development involve the aggregation of individual cells, using cAMP as a chemoattractant. Chemotaxis is initiated when cAMP binds to its receptor, cAR1, and activates the associated G protein, Gα2βγ. However, chemotaxis will not occur unless there is a high density of starving cells present, as measured by high levels of the secreted quorum sensing molecule, CMF. We previously demonstrated that cells lacking PldB bypass the need for CMF and can aggregate at low cell density, whereas cells overexpressing pldB do not aggregate even at high cell density. Here, we found that PldB controlled both cAMP chemotaxis and cell sorting. PldB was also required by CMF to regulate G protein signaling. Specifically, CMF used PldB, to regulate the dissociation of Gα2 from Gβγ. Using fluorescence resonance energy transfer (FRET), we found that along with cAMP, CMF increased the dissociation of the G protein. In fact, CMF augmented the dissociation induced by cAMP. This augmentation was lost in cells lacking PldB. PldB appears to mediate the CMF signal through the production of phosphatidic acid, as exogenously added phosphatidic acid phenocopies overexpression of pldB. These results suggest that phospholipase D activity is required for CMF to alter the kinetics of cAMP-induced G protein signaling.
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Affiliation(s)
- Sibnath Ray
- Department of Biological Sciences, Hunter College, New York, New York 10065, USA
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22
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Fang M, Olivares-Navarrete R, Wieland M, Cochran DL, Boyan BD, Schwartz Z. The role of phospholipase D in osteoblast response to titanium surface microstructure. J Biomed Mater Res A 2010; 93:897-909. [PMID: 19705469 DOI: 10.1002/jbm.a.32596] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Biomaterial surface properties such as microtopography and energy can change cellular responses at the cell-implant interface. Phospholipase D (PLD) is required for the differentiation of osteoblast-like MG63 cells on machined and grit-blasted titanium surfaces. Here, we determined if PLD is also required on microstructured/high-energy substrates and the mechanism involved. shRNAs for human PLD1 and PLD2 were used to silence MG63 cells. Wild-type and PLD1 or PLD1/2 silenced cells were cultured on smooth-pretreatment surfaces (PT); grit-blasted, acid-etched surfaces (SLA); and SLA surfaces modified to have higher surface energy (modSLA). PLD was inhibited with ethanol or activated with 24,25-dihydroxyvitamin-D(3) [24R,25(OH)(2)D(3)]. As surface roughness/energy increased, PLD mRNA and activity increased, cell number decreased, osteocalcin and osteoprotegerin increased, and protein kinase C (PKC) and alkaline phosphatase specific activities increased. Ethanol inhibited PLD and reduced surface effects on these parameters. There was no effect on these parameters after knockdown of PLD1, but PLD1/2 double knockdown had effects comparableto PLD inhibition. 24R,25(OH)(2)D(3) increased PLD activity and the production of osteocalcin and osteoprotegerin, but decreased cell number on the rough/high-energy surfaces. These results confirm that surface roughness/energy-induced PLD activity is required for osteoblast differentiation and that PLD2 is the main isoform involved in this pathway. PLD is activated by 24R,25(OH)(2)D(3) in a surface-dependent manner and inhibition of PLD reduces the effects of surface microstructure/energy on PKC, suggesting that PLD mediates the stimulatory effect of microstructured/high-energy surfaces via PKC-dependent signaling.
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Affiliation(s)
- Mimi Fang
- Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA
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23
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Pleskot R, Potocký M, Pejchar P, Linek J, Bezvoda R, Martinec J, Valentová O, Novotná Z, Zárský V. Mutual regulation of plant phospholipase D and the actin cytoskeleton. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2010; 62:494-507. [PMID: 20149133 DOI: 10.1111/j.1365-313x.2010.04168.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Membrane lipids and cytoskeleton dynamics are intimately inter-connected in the eukaryotic cell; however, only recently have the molecular mechanisms operating at this interface in plant cells been addressed experimentally. Phospholipase D (PLD) and its product phosphatidic acid (PA) were discovered to be important regulators in the membrane-cytoskeleton interface in eukaryotes. Here we report the mechanistic details of plant PLD-actin interactions. Inhibition of PLD by n-butanol compromises pollen tube actin, and PA rescues the detrimental effect of n-butanol on F-actin, showing clearly the importance of the PLD-PA interaction for pollen tube F-actin dynamics. From various candidate tobacco PLDs isoforms, we identified NtPLDbeta1 as a regulatory partner of actin, by both activity and in vitro interaction assays. Similarly to published data, the activity of tobacco PIP(2)-dependent PLD (PLDbeta) is specifically enhanced by F-actin and inhibited by G-actin. We then identified the NtPLDbeta1 domain responsible for actin interactions. Using sequence- and structure-based analysis, together with site-directed mutagenesis, we identified Asn323 and Thr382 of NtPLDbeta1 as the crucial amino acids in the actin-interacting fold. The effect of antisense-mediated suppression of NtPLDbeta1 or NtPLDdelta on pollen tube F-actin dynamics shows that NtPLDbeta1 is the active partner in PLD-actin interplay. The positive feedback loop created by activation of PLDbeta by F-actin and of F-actin by PA provides an important mechanism to locally increase membrane-F-actin dynamics in the cortex of plant cells.
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Affiliation(s)
- Roman Pleskot
- Institute of Experimental Botany, Academy of Sciences of the Czech Republic, v.v.i., Rozvojová 263, 165 02 Prague 6, Czech Republic
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24
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Yang L, Seifert A, Wu D, Wang X, Rankovic V, Schröder H, Brandenburg LO, Höllt V, Koch T. Role of phospholipase D2/phosphatidic acid signal transduction in micro- and delta-opioid receptor endocytosis. Mol Pharmacol 2010; 78:105-13. [PMID: 20354103 DOI: 10.1124/mol.109.063107] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We demonstrated recently that opioid-induced activation of phospholipase D2 (PLD2) enhances mu- (MOPr) and delta-opioid receptor endocytosis/recycling and thus reduces the development of opioid receptor desensitization and tolerance. However, the mechanistic basis for the PLD2-mediated induction of opioid receptor endocytosis is currently unknown. Here we show that PLD2-generated phosphatidic acid (PA) might play a key role in facilitating the endocytosis of opioid receptors. However, PLD2-derived PA is known to be further converted to diacylglycerol (DAG) by PA phosphohydrolase (PPAP2). In fact, blocking of PA phosphohydrolase activity by propranolol or PPAP2-short interfering RNA (siRNA) transfection significantly attenuated agonist-induced opioid receptor endocytosis. The primary importance of PA-derived DAG in the induction of opioid receptor endocytosis was further supported by the finding that increasing the DAG level by inhibiting the reconversion of DAG into PA with the DAG kinase inhibitor 3-[2-(4-[bis-(4-fluorophenyl)methylene]-1-piperidinyl)ethyl]-2,3-dihydro-2-thioxo-4(1H)quinazolinone (R59949) or the addition of the synthetic cell-permeable DAG analog 1,2-dioctanoyl-sn-glycerol (DOG), further increased the agonist-induced opioid receptor endocytosis. Moreover, the addition of DOG bypasses the PLD2-siRNA- or PPAP2-siRNA-mediated impairment of DAG synthesis and resulted in a restoration of agonist-induced opioid receptor internalization. Further studies established a functional link between PA-derived DAG and the activation of p38 mitogen-activated protein kinase (MAPK) and the subsequent phosphorylation of the Rab5 effector early endosome antigen 1, which has been demonstrated recently to be required for the induction of MOPr endocytosis. Taken together, our results revealed that the regulation of opioid receptor endocytosis by PLD2 involves the conversion of its product PA to DAG resulting in an activation of the p38 MAPK pathway.
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Affiliation(s)
- Liquan Yang
- Institute of Pharmacology and Toxicology, Otto-von-Guericke University, 39120 Magdeburg, Leipziger Str. 44, Germany
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25
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Reversible bleb formation in mast cells stimulated with antigen is Ca2+/calmodulin-dependent and bleb size is regulated by ARF6. Biochem J 2009; 425:179-93. [DOI: 10.1042/bj20091122] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Mast cells stimulated with antigen undergo extensive changes in their cytoskeleton. In the present study, we assess the impact of actin-modifying drugs and report that, in the presence of cytochalasin D, mast cells stop membrane ruffling, but instead bleb. Bleb formation is reversible following washout of cytochalasin D and occurs in an actin-polymerization-dependent manner. Bleb formation is inhibited by expression of constitutively active ezrin-T567D. Blebbing is also inhibited by blebbistatin, a myosin II inhibitor, implying myosin II activation in the process. We used a selection of inhibitors and observed that myosin II activation is dependent mainly on Ca2+–calmodulin, with only a small contribution from Rho kinase. The signalling pathways stimulated by antigen include PLC (phospholipase C) and PLD (phospholipase D). Bleb formation was dependent on activation of PLC, but not PLD. Primary alcohols, used previously as a means to reduce PLD-derived phosphatidic acid, were potent inhibitors of membrane blebbing, but a more selective inhibitor of PLD, FIPI (5-fluoro-2-indolyl des-chlorohalopemide), was without effect. FIPI also did not inhibit membrane ruffling or degranulation of mast cells, indicating that inhibition by primary alcohols works through an unidentified mechanism rather than via diversion of PLD activity as assumed. We also examined the requirement for ARF6 (ADP-ribosylation factor 6) and observed that its expression led to an increase in bleb size and a further increase was observed with the dominant-active mutant, ARF6-Q67L. Since ARF6-T27N had no effect on bleb size, we conclude that ARF6 needs to be active to regulate the size of the blebs.
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26
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Li L, Saga N, Mikami K. Ca2+ influx and phosphoinositide signalling are essential for the establishment and maintenance of cell polarity in monospores from the red alga Porphyra yezoensis. JOURNAL OF EXPERIMENTAL BOTANY 2009; 60:3477-89. [PMID: 19531546 PMCID: PMC2724695 DOI: 10.1093/jxb/erp183] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2009] [Revised: 05/12/2009] [Accepted: 05/13/2009] [Indexed: 05/16/2023]
Abstract
The asymmetrical distribution of F-actin directed by cell polarity has been observed during the migration of monospores from the red alga Porphyra yezoensis. The significance of Ca2+ influx and phosphoinositide signalling during the formation of cell polarity in migrating monospores was analysed pharmacologically. The results indicate that the inhibition of the establishment of cell polarity, as judged by the ability of F-actin to localize asymmetrically, cell wall synthesis, and development into germlings, occurred when monospores were treated with inhibitors of the Ca2+ permeable channel, phospholipase C (PLC), diacylglycerol kinase, and inositol-1,4,5-trisphosphate receptor. Moreover, it was also found that light triggered the establishment of cell polarity via photosynthetic activity but not its direction, indicating that the Ca2+ influx and PLC activation required for the establishment of cell polarity are light dependent. By contrast, inhibition of phospholipase D (PLD) prevented the migration of monospores but not the asymmetrical localization of F-actin. Taken together, these findings suggest that there is functional diversity between the PLC and PLD signalling systems in terms of the formation of cell polarity; the former being critical for the light-dependent establishment of cell polarity and the latter playing a role in the maintenance of established cell polarity.
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Affiliation(s)
- Lin Li
- Graduate School of Fisheries Sciences, Hokkaido University, Hakodate 041-8611, Japan
| | - Naotsune Saga
- Faculty of Fisheries Sciences, Hokkaido University, 3-1-1 Minato-cho, Hakodate 041-8611, Japan
| | - Koji Mikami
- Faculty of Fisheries Sciences, Hokkaido University, 3-1-1 Minato-cho, Hakodate 041-8611, Japan
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27
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Emerging findings from studies of phospholipase D in model organisms (and a short update on phosphatidic acid effectors). Biochim Biophys Acta Mol Cell Biol Lipids 2009; 1791:889-97. [PMID: 19345277 DOI: 10.1016/j.bbalip.2009.03.013] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2009] [Revised: 03/19/2009] [Accepted: 03/24/2009] [Indexed: 02/05/2023]
Abstract
Phospholipase D (PLD) catalyses the hydrolysis of phosphatidylcholine to generate phosphatidic acid and choline. Historically, much PLD work has been conducted in mammalian settings although genes encoding enzymes of this family have been identified in all eukaryotic organisms. Recently, important insights on PLD function are emerging from work in yeast, but much less is known about PLD in other organisms. In this review we will summarize what is known about phospholipase D in several model organisms, including C. elegans, D. discoideum, D. rerio and D. melanogaster. In the cases where knockouts are available (C. elegans, Dictyostelium and Drosophila) the PLD gene(s) appear not to be essential for viability, but several studies are beginning to identify pathways where this activity has a role. Given that the proteins in model organisms are very similar to their mammalian counterparts, we expect that future studies in model organisms will complement and extend ongoing work in mammalian settings. At the end of this review we will also provide a short update on phosphatidic acid targets, a topic last reviewed in 2006.
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28
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Nishikimi A, Fukuhara H, Su W, Hongu T, Takasuga S, Mihara H, Cao Q, Sanematsu F, Kanai M, Hasegawa H, Tanaka Y, Shibasaki M, Kanaho Y, Sasaki T, Frohman MA, Fukui Y. Sequential regulation of DOCK2 dynamics by two phospholipids during neutrophil chemotaxis. Science 2009; 324:384-7. [PMID: 19325080 DOI: 10.1126/science.1170179] [Citation(s) in RCA: 222] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
During chemotaxis, activation of the small guanosine triphosphatase Rac is spatially regulated to organize the extension of membrane protrusions in the direction of migration. In neutrophils, Rac activation is primarily mediated by DOCK2, an atypical guanine nucleotide exchange factor. Upon stimulation, we found that DOCK2 rapidly translocated to the plasma membrane in a phosphatidylinositol 3,4,5-trisphosphate-dependent manner. However, subsequent accumulation of DOCK2 at the leading edge required phospholipase D-mediated synthesis of phosphatidic acid, which stabilized DOCK2 there by means of interaction with a polybasic amino acid cluster, resulting in increased local actin polymerization. When this interaction was blocked, neutrophils failed to form leading edges properly and exhibited defects in chemotaxis. Thus, intracellular DOCK2 dynamics are sequentially regulated by distinct phospholipids to localize Rac activation during neutrophil chemotaxis.
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Affiliation(s)
- Akihiko Nishikimi
- Division of Immunogenetics, Department of Immunobiology and Neuroscience, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan
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29
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Kölsch V, Charest PG, Firtel RA. The regulation of cell motility and chemotaxis by phospholipid signaling. J Cell Sci 2008; 121:551-9. [PMID: 18287584 DOI: 10.1242/jcs.023333] [Citation(s) in RCA: 276] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Phosphoinositide 3-kinase (PI3K), PTEN and localized phosphatidylinositol (3,4,5)-trisphosphate [PtdIns(3,4,5)P3] play key roles in chemotaxis, regulating cell motility by controlling the actin cytoskeleton in Dictyostelium and mammalian cells. PtdIns(3,4,5)P3, produced by PI3K, acts via diverse downstream signaling components, including the GTPase Rac, Arf-GTPases and the kinase Akt (PKB). It has become increasingly apparent, however, that chemotaxis results from an interplay between the PI3K-PTEN pathway and other parallel pathways in Dictyostelium and mammalian cells. In Dictyostelium, the phospholipase PLA2 acts in concert with PI3K to regulate chemotaxis, whereas phospholipase C (PLC) plays a supporting role in modulating PI3K activity. In adenocarcinoma cells, PLC and the actin regulator cofilin seem to provide the direction-sensing machinery, whereas PI3K might regulate motility.
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Affiliation(s)
- Verena Kölsch
- Section of Cell and Developmental Biology, Division of Biological Sciences, Center for Molecular Genetics, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0380, USA
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30
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Abstract
The two mammalian phosphatidylcholine (PC)-selective phospholipase D (PLD) enzymes remove the choline head group from PC to produce phosphatidic acid (PA). PA stimulates phosphatidylinositol(4)phosphate 5-kinases, can function as a binding site for membrane proteins, is required for certain membrane fusion or fission events and is an important precursor for the production of diacylglycerol (DAG). Both PA and DAG are lipids that favor negatively curved membranes rather than planar bilayers and can reduce the energetic barrier to membrane fission and fusion. Recent data provide a mechanistic explanation for the role PLDs play in some aspects of membrane traffic and provide an explanation for why some membrane fusion reactions require PA and some do not. PLDs also act as guanosine triphosphatase-activating proteins for dynamin and may participate with dynamin in the process of vesicle fission.
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Affiliation(s)
- Michael G Roth
- Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390-9038, USA.
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Nagasaki A, Inotsume K, Kanada M, Uyeda TQ. Phospholipase D Is Essential for Keratocyte-like Migration of NBT-II Cells. Cell Struct Funct 2008; 33:27-33. [DOI: 10.1247/csf.07042] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Affiliation(s)
- Akira Nagasaki
- Research Institute for Cell Engineering, National Institute of Advanced Industrial Science and Technology (AIST)
| | - Kimiko Inotsume
- Research Institute for Cell Engineering, National Institute of Advanced Industrial Science and Technology (AIST)
- Graduate School of Life and Environmental Sciences, University of Tsukuba
| | - Masamitsu Kanada
- Research Institute for Cell Engineering, National Institute of Advanced Industrial Science and Technology (AIST)
- Graduate School of Life and Environmental Sciences, University of Tsukuba
| | - Taro Q.P. Uyeda
- Research Institute for Cell Engineering, National Institute of Advanced Industrial Science and Technology (AIST)
- Graduate School of Life and Environmental Sciences, University of Tsukuba
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Phagocytosis and host-pathogen interactions in Dictyostelium with a look at macrophages. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2008; 271:253-300. [PMID: 19081545 DOI: 10.1016/s1937-6448(08)01206-9] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Research into phagocytosis and host-pathogen interactions in the lower eukaryote Dictyostelium discoideum has flourished in recent years. This chapter presents a glimpse of where this research stands, with emphasis on the cell biology of the phagocytic process and on the wealth of molecular genetic data that have been gathered. The basic mechanistic machinery and most of the underlying genes appear to be evolutionarily conserved, reflecting the fact that phagocytosis arose as an efficient way to ingest food in single protozoan cells devoid of a rigid cell wall. In spite of some differences, the signal transduction pathways regulating phagosome biogenesis are also emerging as ultimately similar between Dictyostelium and macrophages. Both cell types are hosts for many pathogenic invasive bacteria, which exploit phagocytosis to grow intracellularly. We present an overwiew, based on the analysis of mutants, on how Dictyostelium contributes as a genetic model system to decipher the complexity of host-pathogen interactions.
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Nagasaki A, Uyeda TQP. Screening of genes involved in cell migration in Dictyostelium. Exp Cell Res 2007; 314:1136-46. [PMID: 18164290 DOI: 10.1016/j.yexcr.2007.12.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2007] [Revised: 11/28/2007] [Accepted: 12/02/2007] [Indexed: 11/18/2022]
Abstract
A single cell of wild-type Dictyostelium discoideum forms a visible colony on a plastic dish in several days, but due to enhanced cell migration, amiB-null mutant cells scatter over a large area and do not form noticeable colonies. Here, with an aim to identify genes involved in cell migration, we isolated suppresser mutants of amiB-null mutants that restore the ability to form colonies. From REMI (restriction enzyme-mediated integration)-mutagenized pool of double-mutants, we identified 18 responsible genes from them. These genes can be categorized into several biological processes. One cell line, Sab16 (Suppressor of amiB) was chosen for further analysis, which had a disrupted phospholipase D pldB gene. To confirm the role of pldB gene in cell migration, we knocked out the pldB gene and over-expressed gfp-pldB in wild-type cells. GFP-PLDB localized to plasma membrane and on vesicles, and in migrating cells, at the protruding regions of pseudopodia. Migration speed of vegetative pldB-null cells was reduced to 73% of that of the wild-type. These results suggest that PLDB plays an important role in migration in Dictyostelium cells, and that our screening system is useful for the identification of genes involved in cell migration.
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Affiliation(s)
- Akira Nagasaki
- Research Institute for Cell Engineering, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 4, Tsukuba, Ibaraki, Japan.
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Gomez-Cambronero J, Di Fulvio M, Knapek K. Understanding phospholipase D (PLD) using leukocytes: PLD involvement in cell adhesion and chemotaxis. J Leukoc Biol 2007; 82:272-81. [PMID: 17431093 DOI: 10.1189/jlb.0107033] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Phospholipase D (PLD) is an enzyme that catalyzes the conversion of membrane phosphatidylcholine to choline and phosphatidic acid (PA; a second messenger). PLD is expressed in nearly all types of leukocytes and has been associated with phagocytosis, degranulation, microbial killing, and leukocyte maturation. With the application of recently developed molecular tools (i.e., expression vectors, silencing RNA, and specific antibodies), the demonstration of a key role for PLD in those and related cellular actions has contributed to a better awareness of its importance. A case in point is the recent findings that RNA interference-mediated depletion of PLD results in impaired leukocyte adhesion and chemotaxis toward a gradient of chemokines, implying that PLD is necessary for leukocyte movement. We forecast that based on results such as those, leukocytes may prove to be useful tools to unravel still-unresolved mechanistic issues in the complex biology of PLD. Three such issues are considered here: first, whether the cellular actions of PLD are mediated entirely by PA (the product of its enzymatic reaction) or whether PLD by itself interacts with other protein signaling molecules; second, the current difficulty of defining a "PA consensus site" in the various intracellular protein targets of PA; and third, the resolution of specific PLD location (upstream or downstream) in a particular effector signaling cascade. There are reasons to expect that leukocytes and their leukemic cell line counterparts will continue yielding invaluable information to cell biologists to resolve standing molecular and functional issues concerning PLD.
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Affiliation(s)
- Julian Gomez-Cambronero
- Wright State University School of Medicine, 3640 Colonel Glenn Highway, Dayton, OH 45435, USA.
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Stable adhesion and migration of human neutrophils requires phospholipase D-mediated activation of the integrin CD11b/CD18. Mol Immunol 2007; 44:3211-21. [PMID: 17346796 DOI: 10.1016/j.molimm.2007.01.033] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2007] [Accepted: 01/20/2007] [Indexed: 01/31/2023]
Abstract
The pathways regulating integrin-mediated adhesion during neutrophil migration are incompletely defined. Using a flow-based model in which human neutrophils rolling on P-selectin were activated to migrate by the chemoattractant peptide fMLP, we investigated the role of phospholipase D (PLD). fMLP-stimulated PLD generation of phosphatidate (PtdOH); while inhibition of PtdOH production with butan-1-ol had no effect on the initial immobilisation of rolling neutrophils (supported by activation of constitutively surface-expressed beta(2)-integrin CD11b/CD18) it impaired longer-term stability of adhesion and reduced the rate of migration (supported by activation of de novo-exocytosed CD11b/CD18). PtdOH regulated these processes by controlling activation of exocytosed CD11b/CD18, and appeared to act by directly stimulating phosphatidylinositol 4-phosphate 5-kinase type I to generate phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P(2)). Cell-permeable PtdIns(4,5)P(2) recovered migration of neutrophils after PLD inhibition; PtdIns(4,5)P(2) appeared to act by promoting talin binding to CD18 and hence activating CD11b/CD18, as migration was inhibited when neutrophils were loaded with peptides previously shown to block the interaction between PtdIns(4,5)P(2) and talin or talin and CD18. Thus, these data indicate that PLD-synthesised PtdOH stimulates the generation of PtdIns(4,5)P(2), which in turn mediates talin binding to, and activation of, CD11b/CD18 required for neutrophil stable adhesion and migration.
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Jarquin-Pardo M, Fitzpatrick A, Galiano FJ, First EA, Davis JN. Phosphatidic acid regulates the affinity of the murine phosphatidylinositol 4-phosphate 5-kinase-Ibeta for phosphatidylinositol-4-phosphate. J Cell Biochem 2007; 100:112-28. [PMID: 16888807 DOI: 10.1002/jcb.21027] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Type I phosphatidylinositol 4-phosphate 5-kinase (PI4P5K) catalyzes the phosphorylation of phosphatidylinositol 4 phosphate [PI(4)P] at carbon 5, producing phosphatidylinositol 4,5 bisphosphate [PI(4,5)P2]. Phosphatidic acid (PA) activates PI4P5K in vitro and plays a central role in the activation of PIP5K pathways in vivo. This report demonstrates that actin fiber formation in murine fibroblasts involves PA activation of PIP5Ks and defines biochemical interactions between PA and the PIP5Ks. Inhibition of phospholipase D production of PA results in the loss of actin fibers. Overexpression of the beta isoform of the type I murine phosphatidylinositol 4-phosphate 5-kinase (mPIP5K-Ibeta) maintains actin fiber structure in the face of phospholipase D inhibition. PA activates mPIP5K-Ibeta by direct binding to mPIP5K-Ibeta through both electrostatic and hydrophobic interactions, with the fatty acid acyl chain length and degree of saturation acting as critical determinants of binding and activation. Furthermore, kinetic analysis suggests that phosphorylation of the PI(4)P substrate does not follow classical Michaelis-Menten kinetics. Instead, the kinetic data are consistent with a model in which mPIP5K-Ibeta initially binds to the lipid micelle and subsequently binds the PI(4)P substrate. In addition, the kinetics indicate substrate inhibition, suggesting that mPIP5K-Ibeta contains an inhibitory PI(4)P-binding site. These results suggest a model in which mPIP5K-Ibeta is surrounded by PI(4)P, but is unable to catalyze its conversion to PI(4,5)P2 unless PA is bound.
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Affiliation(s)
- Marta Jarquin-Pardo
- Feist-Weiller Cancer Center and Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, Louisiana 71130-3932, USA
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Farquhar MJ, Powner DJ, Levine BA, Wright MH, Ladds G, Hodgkin MN. Interaction of PLD1b with actin in antigen-stimulated mast cells. Cell Signal 2007; 19:349-58. [PMID: 16978840 DOI: 10.1016/j.cellsig.2006.07.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2006] [Revised: 06/16/2006] [Accepted: 07/19/2006] [Indexed: 11/26/2022]
Abstract
Phosphatidic acid, the product of phospholipase D catalysed phosphatidylcholine hydrolysis is an important signalling molecule that has been implicated in regulation of actin cytoskeleton remodelling and secretion from mast cells. We show that human PLD1b (hPLD1b) is an actin-binding protein and the N-terminus is predominantly involved in this interaction. Protein kinase C (PKC) is a major upstream regulator of PLD activity and PKC phosphorylation sites have been identified within the N-terminus of PLD1b at serine 2 and threonine 147. Over-expression of wild type hPLD1b in mast cells showed that antigen stimulation significantly enhanced co-localisation of PLD1b with actin structures. Mutation of serine 2 to alanine abolished antigen-induced co-localisation whereas mutation of threonine 147 had less dramatic effects on co-localisation. The absence of co-localisation of PLD1b (S2A) with actin coincides with a significant decrease in PLD activity in cells expressing the PLD1b (S2A) mutant. In resting RBL-2H3 cells, mutation of serine 2 to aspartate resulted in constitutive co-localisation of PLD with the actin cytoskeleton, coincident with restored PLD activity. These results reveal that serine 2 is an important regulatory site involved in controlling PLD enzyme activity and the interaction between PLD and actin.
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Affiliation(s)
- M J Farquhar
- Molecular Physiology Group, Department of Biological Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom
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38
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Lee JG, Lee SH, Park DW, Bae YS, Yun SS, Kim JR, Baek SH. Phosphatidic acid as a regulator of matrix metalloproteinase-9 expression via the TNF-α signaling pathway. FEBS Lett 2007; 581:787-93. [PMID: 17276429 DOI: 10.1016/j.febslet.2007.01.048] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2007] [Accepted: 01/22/2007] [Indexed: 12/24/2022]
Abstract
Phosphatidic acid (PA) is implicated in pathophysiological processes associated with cellular signaling events and inflammation, which include the expressional regulation of numerous genes. Here, we show that PA stimulation increases matrix metalloproteinase-9 (MMP-9) expression in macrophages through tumor necrosis factor (TNF)-alpha signaling. We performed antibody array analysis on proteins from macrophages stimulated with PA. PA was found to induce the production of TNF-alpha, but not of TNF receptor (TNFR)1 and TNFR2 in a time-dependent manner and stimulated significant, though delayed, MMP-9 expression. PA induced the phosphorylations of both ERK1/2 and p38, but not of c-jun amino-terminal kinase. Moreover, only ERK1/2 inhibition by U0126 suppressed PA-induced TNF-alpha production and MMP-9 expression. Neutralizing TNF-alpha, TNFR1 or TNFR2 antibodies significantly suppressed PA-induced MMP-9 expression, suggesting that the production of TNF-alpha in response to PA preceded the expression of MMP-9. Moreover, lipopolysaccharide-induced PA also led to TNF-alpha release and resulted in MMP-9 expression. Taken together, these observations suggest that PA may play a role in MMP-9 regulation through ERKs/TNF-alpha/TNFRs-dependent signaling pathway.
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Affiliation(s)
- Jin-Gu Lee
- Department of Biochemistry & Molecular Biology, Aging-Associated Vascular Disease Research Center, Yeungnam University, Daegu 705-717, Republic of Korea
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Lamour KH, Finley L, Hurtado-Gonzales O, Gobena D, Tierney M, Meijer HJG. Targeted gene mutation in Phytophthora spp. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2006; 19:1359-67. [PMID: 17153920 DOI: 10.1094/mpmi-19-1359] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The genus Phytophthora belongs to the oomycetes and is composed of plant pathogens. Currently, there are no strategies to mutate specific genes for members of this genus. Whole genome sequences are available or being prepared for Phytophthora sojae, P. ramorum, P. infestans, and P. capsici and the development of molecular biological techniques for functional genomics is encouraged. This article describes the adaptation of the reverse-genetic strategy of targeting induced local lesions in genomes (TILLING) to isolate gene-specific mutants in Phytophthora spp. A genomic library of 2,400 ethylnitrosourea (ENU) mutants of P. sojae was created and screened for induced point mutations in the genes encoding a necrosisinducing protein (PsojNIP) and a Phytophthora-specific phospholipase D (PsPXTM-PLD). Mutations were detected in single individuals and included silent, missense, and nonsense changes. Homozygous mutant isolates carrying a potentially deleterious missense mutation in PsojNIP and a premature stop codon in PsPXTM-PLD were identified. No phenotypic effect has yet been found for the homozygous mutant of PsojNIP. For those of PsPXTM-PLD, a reduction in growth rate and an appressed mycelial growth was observed. This demonstrates the feasibility of target-selected gene disruption for Phytophthora spp. and adds an important tool for functional genomic investigation.
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Affiliation(s)
- Kurt H Lamour
- Department of Entomology and Plant Pathology, The University of Tennessee, Rm 205 Ellington Plant Science, 2431 Joe Johnson Dr., Knoxville 37996, USA.
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Snyder MD, Pierce SK. A mutation in Epstein-Barr virus LMP2A reveals a role for phospholipase D in B-Cell antigen receptor trafficking. Traffic 2006; 7:993-1006. [PMID: 16882041 DOI: 10.1111/j.1600-0854.2006.00450.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Epstein-Barr virus (EBV) latent infection of B cells blocks the interrelated signaling and antigen-trafficking functions of the BCR through the activity of its latent membrane protein 2A (LMP2A). At present, the molecular mechanisms by which LMP2A exerts its control of BCR functions are only poorly understood. Earlier studies showed that in B cells expressing LMP2A containing a tyrosine mutation at position 112 in its cytoplasmic domain (Y112-LMP2A), the BCR could initiate signaling but could not properly traffic antigen for processing. Here, we show that BCR signaling in Y112-LMP2A-expressing cells is attenuated with a reduction in both the degree and duration of phosphorylation of key components of the BCR signaling cascade including Syk, BLNK, PI3K, and Btk. Notably, Y112-LMP2A expression completely blocked the BCR-induced activation of phospholipase D (PLD), a lipase implicated in the intracellular trafficking of a variety of surface receptors. We show that blocking PLD activity, by expressing Y112-LMP2A, treating cells with the PLD inhibitor 1-butanol or reducing PLD expression by siRNA, blocked BCR trafficking to class II-containing compartments. Moreover, Y112-LMP2A expression blocked the recruitment of phosphorylated forms of the downstream BCR signaling components, Erk and JNK, through both PLD-dependent and PLD-independent mechanisms. Thus, the investigation of the mechanism by which Y112-LMP2A blocks BCR function revealed an essential role for PLD in BCR trafficking for antigen processing.
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Affiliation(s)
- Michelle D Snyder
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA
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41
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Boucrot E, Saffarian S, Massol R, Kirchhausen T, Ehrlich M. Role of lipids and actin in the formation of clathrin-coated pits. Exp Cell Res 2006; 312:4036-48. [PMID: 17097636 PMCID: PMC2785547 DOI: 10.1016/j.yexcr.2006.09.025] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2006] [Revised: 09/06/2006] [Accepted: 09/07/2006] [Indexed: 11/20/2022]
Abstract
Assembly of clathrin-coated pits and their maturation into coated vesicles requires coordinated interactions between specific lipids and several structural and regulatory proteins. In the presence of primary alcohols, phospholipase D generates phosphatidylalcohols instead of PA, reducing stimulation of phosphatidyl inositol 5-kinase (PI5K) and hence decreasing formation of phosphoinositide-4,5-biphosphate (PIP(2)). Using live-cell imaging, we have shown that acute treatment of cells with 1-butanol or other small primary alcohols induces rapid disassembly of coated pits at the plasma membrane and blocks appearance of new ones. Addition of exogenous PIP(2) reverses this effect. Coated pits and vesicles reappear synchronously upon removal of 1-butanol; we have used this synchrony to assess the role of actin in coated vesicle assembly. Prolonged inhibition of actin polymerization by latrunculin A or cytochalasin D reduced by approximately 50% the frequency of coated pit formation without affecting maturation into coated vesicles. As in control cells, removal of 1-butanol in the continued presence of an actin depolymerizer led to synchronous appearance of new pits, which matured normally. Thus, remodeling of the actin cytoskeleton is not essential for clathrin-coated vesicle assembly but may indirectly affect the nucleation of clathrin-coated pits.
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Affiliation(s)
- Emmanuel Boucrot
- Department of Cell Biology and the CBR Institute for Biomedical Research, Harvard Medical School, Boston, 200 Longwood Ave, MA 02115 USA
| | - Saveez Saffarian
- Department of Cell Biology and the CBR Institute for Biomedical Research, Harvard Medical School, Boston, 200 Longwood Ave, MA 02115 USA
| | - Ramiro Massol
- Department of Cell Biology and the CBR Institute for Biomedical Research, Harvard Medical School, Boston, 200 Longwood Ave, MA 02115 USA
| | - Tomas Kirchhausen
- Department of Cell Biology and the CBR Institute for Biomedical Research, Harvard Medical School, Boston, 200 Longwood Ave, MA 02115 USA
| | - Marcelo Ehrlich
- Department of Cell Research and Immunology, Tel Aviv University, Tel Aviv, Israel
- *Corresponding author. Department of Cell Research and Immunology, Tel Aviv University, Tel Aviv, Israel, Phone:972-3-6409406; Fax:972-3-6420246 E-Mail:
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Vlahou G, Rivero F. Rho GTPase signaling in Dictyostelium discoideum: Insights from the genome. Eur J Cell Biol 2006; 85:947-59. [PMID: 16762450 DOI: 10.1016/j.ejcb.2006.04.011] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Rho GTPases are ubiquitously expressed across the eukaryotes where they act as molecular switches participating in the regulation of many cellular processes. We present an inventory of proteins involved in Rho-regulated signaling pathways in Dictyostelium discoideum that have been identified in the completed genome sequence. In Dictyostelium the Rho family is encoded by 18 genes and one pseudogene. Some of the Rho GTPases (Rac1a/b/c, RacF1/F2 and RacB) are members of the Rac subfamily, and one, RacA, belongs to the RhoBTB subfamily. The Cdc42 and Rho subfamilies, characteristic of metazoa and fungi, are absent. The activities of these GTPases are regulated by two members of the RhoGDI family, by eight members of the Dock180/zizimin family and by a surprisingly large number of proteins carrying RhoGEF (42 genes) or RhoGAP (43 genes) domains or both (three genes). Most of these show domain compositions not found in other organisms, although some have clear homologs in metazoa and/or fungi. Among the (in many cases putative) effectors found in Dictyostelium are the CRIB domain proteins (WASP and two related proteins, eight PAK kinases and a novel gelsolin-related protein), components of the Scar/WAVE complex, 10 formins, four IQGAPs, two members of the PCH family, numerous lipid kinases and phospholipases, and components of the NADPH oxidase and the exocyst complexes. In general, the repertoire of Rho signaling components of Dictyostelium is similar to that of metazoa and fungi.
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Affiliation(s)
- Georgia Vlahou
- Center for Biochemistry of the Medical Faculty and Center for Molecular Medicine Cologne, University of Cologne, Joseph-Stelzmann-Str. 52, D-50931 Cologne, Germany
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Lehman N, Di Fulvio M, McCray N, Campos I, Tabatabaian F, Gomez-Cambronero J. Phagocyte cell migration is mediated by phospholipases PLD1 and PLD2. Blood 2006; 108:3564-72. [PMID: 16873675 PMCID: PMC1895436 DOI: 10.1182/blood-2006-02-005959] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
We have investigated whether the signaling protein phospholipase D is implicated in leukocyte cell motility. Treating differentiated HL-60 cells with small interfering RNAs (siRNAs), to deplete endogenous expression of the PLD1 isoform, led to an abolishment of basal chemokinesis that could not be rescued with chemoattractants ENA-78, FMLP, and IL-8. Transient overexpression of PLD1 increased both chemokinesis and chemotaxis toward IL-8 and FMLP but not toward ENA-78. Chemokinesis was not mediated by the enzymatic activity of PLD1, but the chemotactic response was, because a lipase-inactive mutant (PLD1-K830R) negated all chemokine-induced potentiating actions and because IL-8 and FMLP increased activity in vitro. Gene expression silencing of the other mammalian isoform, PLD2, also led to cell migration arrest, whereas ENA-78 selectively increased endogenous PLD2 activity and chemotaxis of HL-60 cells overexpressing a myc-pcDNA-PLD2 construct. Thus, PLD1 is differentially activated by CXCR-1, whereas CXCR-2 (and possibly CXCR-1) mediates PLD2 activation. Finally, immunofluorescence microscopy showed that both isoforms were associated with cell polarity and directionality concomitantly with adhesion and F-actin polymerization in response to IL-8. These data represent the first demonstration of the involvement of PLD and its enzymatic activity toward chemokines in the key physiologic process of leukocyte migration.
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Affiliation(s)
- Nicholas Lehman
- Department of Cell Biology and Physiology, Wright State University School of Medicine, Dayton, OH 45435, USA
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Iyer SS, Agrawal RS, Thompson CR, Thompson S, Barton JA, Kusner DJ. Phospholipase D1 Regulates Phagocyte Adhesion. THE JOURNAL OF IMMUNOLOGY 2006; 176:3686-96. [PMID: 16517737 DOI: 10.4049/jimmunol.176.6.3686] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Adhesion is a fundamental cellular response that is essential to the physiologic processes of development, differentiation, proliferation, and motility, as well as to the pathology of inflammation, transformation, and metastasis. Adhesion of phagocytic leukocytes is a critical modulator of antimicrobial and cytotoxic functions, including the respiratory burst, secretion, and apoptosis. Because phospholipase D (PLD) is linked to several signaling pathways implicated in these processes, we tested the hypothesis that PLD regulates phagocyte adhesion. Adhesion of primary human neutrophils and monocyte-derived macrophages to fibronectin was accompanied by marked stimulation of PLD activity. Similarly, adhesion of both human (PLB, THP-1) and murine (RAW) myeloid-macrophage cell lines to fibronectin, fibrinogen, collagen, or plastic resulted in significant activation of PLD. Stimulation of PLD activity was rapid and persisted for at least 90 min. Confocal microscopy indicated that PLD1 exhibited partial colocalization with actin filaments at the adherent interface, in proximity to the focal adhesion protein, paxillin. Reductions in PLD activity by chemical inhibitors or specific short-interfering RNA-induced knockdown of PLD1 resulted in significant inhibition of phagocyte adhesion and was accompanied by reductions in total cellular F-actin. These data support the hypotheses that adhesion stimulates PLD activity, and that PLD1 regulates the initial stages of phagocyte adhesion. Stimulation of PLD activity may promote adhesion-dependent phagocyte effector responses.
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Affiliation(s)
- Shankar S Iyer
- Inflammation Program, Division of Infectious Diseases, Department of Internal Medicine, University of Iowa Carver College of Medicine, 2501 Crosspark Road, Iowa City, IA 52242, USA
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Riedel CG, Mazza M, Maier P, Körner R, Knop M. Differential Requirement for Phospholipase D/Spo14 and Its Novel Interactor Sma1 for Regulation of Exocytotic Vesicle Fusion in Yeast Meiosis. J Biol Chem 2005; 280:37846-52. [PMID: 16148007 DOI: 10.1074/jbc.m504244200] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
During sporulation and meiosis of budding yeast a developmental program determines the formation of the new plasma membranes of the spores. This process of prospore membrane (PSM) formation leads to the formation of meiotic daughter cells, the spores, within the lumen of the mother cell. It is initiated at the spindle pole bodies during meiosis II. Spore formation, but not meiotic cell cycle progression, requires the function of phospholipase D (PLD/Spo14). Here we show that PLD/Spo14 forms a complex with Sma1, a meiotically expressed protein essential for spore formation. Detailed analysis revealed that both proteins are required for early steps of prospore membrane assembly but with distinct defects in the respective mutants. In the Deltaspo14 mutant the initiation of PSM formation is blocked and aggregated vesicles of homogenous size are detected at the spindle pole bodies. In contrast, initiation of PSM formation does occur in the Deltasma1 mutant, but the enlargement of the membrane is impaired. During PSM growth both Spo14 and Sma1 localize to the membrane, and localization of Spo14 is independent of Sma1. Biochemical analysis revealed that Sma1 is not necessary for PLD activity per se and that PLD present in a complex with Sma1 is highly active. Together, our results suggest that yeast PLD is involved in two distinct but essential steps during the regulated vesicle fusion necessary for the assembly of the membranous encapsulations of the spores.
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Affiliation(s)
- Christian G Riedel
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
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