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Kalita E, Panda M, Rao A, Pandey RK, Prajapati VK. Viral mimicry and endocrine system: Divulging the importance in host-microbial crosstalk. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2024; 142:421-436. [PMID: 39059993 DOI: 10.1016/bs.apcsb.2024.03.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/28/2024]
Abstract
Host-pathogen interactions are complex associations which evolve over long co-evolutionary histories. Pathogens exhibit different mechanisms to gain advantage over their host. Mimicry of host factors is an influential tool in subverting host mechanisms to ensure pathogenesis. This chapter discusses such molecular mimicry exhibited during viral infections. Understanding the evolutionary relationships, shared identity and functional impact of the virus encoded mimics is critical. With a particular emphasis on viral mimics and their association with cancer and autoimmune diseases, this chapter highlights the importance of molecular mimicry in virus biology.
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Affiliation(s)
- Elora Kalita
- Life Science Research Centre, Faculty of Science, University of Ostrava, Ostrava, Czechia
| | - Mamta Panda
- Department of Neurology, Experimental Research in Stroke and Inflammation (ERSI), University Medical Center Hamburg-Eppendorf Martinistraße, Hamburg, Germany
| | - Abhishek Rao
- Department of Biochemistry, Central University of Rajasthan, Rajasthan, India
| | - Rajan Kumar Pandey
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Vijay Kumar Prajapati
- Department of Biochemistry, University of Delhi South Campus, Dhaula Kuan, New Delhi, India.
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2
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Banushi B, Joseph SR, Lum B, Lee JJ, Simpson F. Endocytosis in cancer and cancer therapy. Nat Rev Cancer 2023:10.1038/s41568-023-00574-6. [PMID: 37217781 DOI: 10.1038/s41568-023-00574-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/11/2023] [Indexed: 05/24/2023]
Abstract
Endocytosis is a complex process whereby cell surface proteins, lipids and fluid from the extracellular environment are packaged, sorted and internalized into cells. Endocytosis is also a mechanism of drug internalization into cells. There are multiple routes of endocytosis that determine the fate of molecules, from degradation in the lysosomes to recycling back to the plasma membrane. The overall rates of endocytosis and temporal regulation of molecules transiting through endocytic pathways are also intricately linked with signalling outcomes. This process relies on an array of factors, such as intrinsic amino acid motifs and post-translational modifications. Endocytosis is frequently disrupted in cancer. These disruptions lead to inappropriate retention of receptor tyrosine kinases on the tumour cell membrane, changes in the recycling of oncogenic molecules, defective signalling feedback loops and loss of cell polarity. In the past decade, endocytosis has emerged as a pivotal regulator of nutrient scavenging, response to and regulation of immune surveillance and tumour immune evasion, tumour metastasis and therapeutic drug delivery. This Review summarizes and integrates these advances into the understanding of endocytosis in cancer. The potential to regulate these pathways in the clinic to improve cancer therapy is also discussed.
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Affiliation(s)
- Blerida Banushi
- Frazer Institute, University of Queensland, Woolloongabba, Queensland, Australia
| | - Shannon R Joseph
- Frazer Institute, University of Queensland, Woolloongabba, Queensland, Australia
| | - Benedict Lum
- Frazer Institute, University of Queensland, Woolloongabba, Queensland, Australia
| | - Jason J Lee
- Frazer Institute, University of Queensland, Woolloongabba, Queensland, Australia
| | - Fiona Simpson
- Frazer Institute, University of Queensland, Woolloongabba, Queensland, Australia.
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3
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Salloum G, Bresnick AR, Backer JM. Macropinocytosis: mechanisms and regulation. Biochem J 2023; 480:335-362. [PMID: 36920093 DOI: 10.1042/bcj20210584] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 02/22/2023] [Accepted: 02/27/2023] [Indexed: 03/16/2023]
Abstract
Macropinocytosis is defined as an actin-dependent but coat- and dynamin-independent endocytic uptake process, which generates large intracellular vesicles (macropinosomes) containing a non-selective sampling of extracellular fluid. Macropinocytosis provides an important mechanism of immune surveillance by dendritic cells and macrophages, but also serves as an essential nutrient uptake pathway for unicellular organisms and tumor cells. This review examines the cell biological mechanisms that drive macropinocytosis, as well as the complex signaling pathways - GTPases, lipid and protein kinases and phosphatases, and actin regulatory proteins - that regulate macropinosome formation, internalization, and disposition.
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Affiliation(s)
- Gilbert Salloum
- Department of Molecular Pharamacology, Albert Einstein College of Medicine, Bronx, NY, U.S.A
| | - Anne R Bresnick
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY, U.S.A
| | - Jonathan M Backer
- Department of Molecular Pharamacology, Albert Einstein College of Medicine, Bronx, NY, U.S.A
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY, U.S.A
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Abstract
The distinct movements of macropinosome formation and maturation have corresponding biochemical activities which occur in a defined sequence of stages and transitions between those stages. Each stage in the process is regulated by variously phosphorylated derivatives of phosphatidylinositol (PtdIns) which reside in the cytoplasmic face of the membrane lipid bilayer. PtdIns derivatives phosphorylated at the 3' position of the inositol moiety, called 3' phosphoinositides (3'PIs), regulate different stages of the sequence. 3'PIs are synthesized by numerous phosphoinositide 3'-kinases (PI3K) and other lipid kinases and phosphatases, which are themselves regulated by small GTPases of the Ras superfamily. The combined actions of these enzymes localize four principal species of 3'PI to distinct domains of the plasma membrane or to discrete organelles, with distinct biochemical activities confined to those domains. Phosphatidylinositol (3,4,5)-trisphosphate (PtdIns(3,4,5)P3) and phosphatidylinositol (3,4)-bisphosphate (PtdIns(3,4)P2) regulate the early stages of macropinosome formation, which include cell surface ruffling and constrictions of circular ruffles which close into macropinosomes. Phosphatidylinositol 3-phosphate (PtdIns3P) regulates macropinosome fusion with other macropinosomes and early endocytic organelles. Phosphatidylinositol (3,5)-bisphosphate (PtdIns(3,5)P2) mediates macropinosome maturation and shrinkage, through loss of ions and water, and subsequent traffic to lysosomes. The different characteristic rates of macropinocytosis in different cell types indicate levels of regulation which may be governed by the cell's capacity to generate 3'PIs.
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Affiliation(s)
- Joel A Swanson
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, USA.
| | - Nobukazu Araki
- Department of Histology and Cell Biology, School of Medicine, Kagawa University, Miki, Kagawa, Japan
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5
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Ivanova D, Imig C, Camacho M, Reinhold A, Guhathakurta D, Montenegro-Venegas C, Cousin MA, Gundelfinger ED, Rosenmund C, Cooper B, Fejtova A. CtBP1-Mediated Membrane Fission Contributes to Effective Recycling of Synaptic Vesicles. Cell Rep 2021; 30:2444-2459.e7. [PMID: 32075774 PMCID: PMC7034063 DOI: 10.1016/j.celrep.2020.01.079] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 12/12/2019] [Accepted: 01/22/2020] [Indexed: 01/08/2023] Open
Abstract
Compensatory endocytosis of released synaptic vesicles (SVs) relies on coordinated signaling at the lipid-protein interface. Here, we address the synaptic function of C-terminal binding protein 1 (CtBP1), a ubiquitous regulator of gene expression and membrane trafficking in cultured hippocampal neurons. In the absence of CtBP1, synapses form in greater density and show changes in SV distribution and size. The increased basal neurotransmission and enhanced synaptic depression could be attributed to a higher vesicular release probability and a smaller fraction of release-competent SVs, respectively. Rescue experiments with specifically targeted constructs indicate that, while synaptogenesis and release probability are controlled by nuclear CtBP1, the efficient recycling of SVs relies on its synaptic expression. The ability of presynaptic CtBP1 to facilitate compensatory endocytosis depends on its membrane-fission activity and the activation of the lipid-metabolizing enzyme PLD1. Thus, CtBP1 regulates SV recycling by promoting a permissive lipid environment for compensatory endocytosis.
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Affiliation(s)
- Daniela Ivanova
- RG Presynaptic Plasticity, Leibniz Institute for Neurobiology, Magdeburg, Germany; Department of Neurochemistry and Molecular Biology, Leibniz Institute for Neurobiology, Magdeburg, Germany; Molecular Psychiatry, Department of Psychiatry and Psychotherapy, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Cordelia Imig
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, 37075 Göttingen, German
| | - Marcial Camacho
- Institute of Neurophysiology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Annika Reinhold
- Institute of Neurophysiology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Debarpan Guhathakurta
- Molecular Psychiatry, Department of Psychiatry and Psychotherapy, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | | | - Michael A Cousin
- Centre for Discovery Brain Sciences, Hugh Robson Building, George Square, University of Edinburgh, EH9 9XD Edinburgh, UK
| | - Eckart D Gundelfinger
- Department of Neurochemistry and Molecular Biology, Leibniz Institute for Neurobiology, Magdeburg, Germany; Center for Behavioral Brain Science and Medical Faculty, Otto von Guericke University Magdeburg, Magdeburg, Germany
| | - Christian Rosenmund
- Institute of Neurophysiology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Benjamin Cooper
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, 37075 Göttingen, German
| | - Anna Fejtova
- RG Presynaptic Plasticity, Leibniz Institute for Neurobiology, Magdeburg, Germany; Department of Neurochemistry and Molecular Biology, Leibniz Institute for Neurobiology, Magdeburg, Germany; Molecular Psychiatry, Department of Psychiatry and Psychotherapy, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany.
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6
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Bowling FZ, Frohman MA, Airola MV. Structure and regulation of human phospholipase D. Adv Biol Regul 2021; 79:100783. [PMID: 33495125 DOI: 10.1016/j.jbior.2020.100783] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 12/22/2020] [Accepted: 12/28/2020] [Indexed: 12/13/2022]
Abstract
Mammalian phospholipase D (PLD) generates phosphatidic acid, a dynamic lipid secondary messenger involved with a broad spectrum of cellular functions including but not limited to metabolism, migration, and exocytosis. As a promising pharmaceutical target, the biochemical properties of PLD have been well characterized. This has led to the recent crystal structures of human PLD1 and PLD2, the development of PLD specific pharmacological inhibitors, and the identification of cellular regulators of PLD. In this review, we discuss the PLD1 and PLD2 structures, PLD inhibition by small molecules, and the regulation of PLD activity by effector proteins and lipids.
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Affiliation(s)
- Forrest Z Bowling
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY, USA
| | - Michael A Frohman
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY, USA
| | - Michael V Airola
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY, USA.
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7
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Matovelo SA, Zhang L, Mohamed NNI, Kajimoto T, Ijuin T, Okada T, Nakamura SI. Involvement of Receptor-Mediated S1P Signaling in EGF-Induced Macropinocytosis in COS7 Cells. THE KOBE JOURNAL OF MEDICAL SCIENCES 2020; 66:E94-E101. [PMID: 33431782 PMCID: PMC7837661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 07/02/2020] [Indexed: 06/12/2023]
Abstract
Macropinocytosis is a highly conserved cellular process of endocytosis by which extracellular fluid and nutrients are taken up into cells through large, heterogeneous vesicles known as macropinosomes. Growth factors such as epidermal growth factor (EGF) can induce macropinocytosis in many types of cells, although precise mechanism underlying EGF-induced macropinocytosis remains unclear. In the present studies we have shown the involvement of S1P signaling in EGF-induced macropinocytosis in COS7 cells. First, EGF-induced macropinocytosis was strongly impaired in sphingosine kinase isozymes, SphK1 or SphK2-depleted cells, which was completely rescued by the expression of the corresponding wild-type isozyme but not the catalytically inactive one, suggesting the involvement of sphingosine 1-phosphate (S1P) in this phenomenon. Next, we observed that EGF-induced macropinocytosis was strongly inhibited in S1P type 1 receptor (S1P1R)-knockdown cells, implying involvement of S1P1R in this event. Furthermore, we could successfully demonstrate EGF-induced trans-activation of S1P1R using one-molecular fluorescence resonance energy transfer (FRET) technique. Moreover, for EGF-induced Rac1 activation, a step essential to F-actin formation and subsequent macropinocytosis, S1P signaling is required for its full activation, as judged by FRET analysis. These findings indicate that growth factors such as EGF utilize receptor-mediated S1P signaling for the regulation of macropinocytosis to fulfil vital cell activity.
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Affiliation(s)
- Shubi Ambwene Matovelo
- Division of Biochemistry, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
| | - Lifang Zhang
- Division of Biochemistry, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
- Department of Neurosurgery, The Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan 646000, China
| | - Nesma Nabil Ibrahim Mohamed
- Division of Biochemistry, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
- Department of Agricultural Biochemistry, Faculty of Agriculture, Ain shams University, Cairo, Egypt
| | - Taketoshi Kajimoto
- Division of Biochemistry, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
| | - Takeshi Ijuin
- Division of Biochemistry, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
| | - Taro Okada
- Division of Biochemistry, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
| | - Shun-Ichi Nakamura
- Division of Biochemistry, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
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8
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Walpole GFW, Grinstein S. Endocytosis and the internalization of pathogenic organisms: focus on phosphoinositides. F1000Res 2020; 9. [PMID: 32494357 PMCID: PMC7233180 DOI: 10.12688/f1000research.22393.1] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/07/2020] [Indexed: 12/18/2022] Open
Abstract
Despite their comparatively low abundance in biological membranes, phosphoinositides are key to the regulation of a diverse array of signaling pathways and direct membrane traffic. The role of phosphoinositides in the initiation and progression of endocytic pathways has been studied in considerable depth. Recent advances have revealed that distinct phosphoinositide species feature prominently in clathrin-dependent and -independent endocytosis as well as in phagocytosis and macropinocytosis. Moreover, a variety of intracellular and cell-associated pathogens have developed strategies to commandeer host cell phosphoinositide metabolism to gain entry and/or metabolic advantage, thereby promoting their survival and proliferation. Here, we briefly survey the current knowledge on the involvement of phosphoinositides in endocytosis, phagocytosis, and macropinocytosis and highlight several examples of molecular mimicry employed by pathogens to either “hitch a ride” on endocytic pathways endogenous to the host or create an entry path of their own.
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Affiliation(s)
- Glenn F W Walpole
- Program in Cell Biology, Hospital for Sick Children, Toronto, ON, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Sergio Grinstein
- Program in Cell Biology, Hospital for Sick Children, Toronto, ON, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada.,Keenan Research Centre of the Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, ON, Canada
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9
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Abstract
Macropinosome formation occurs as a localized sequence of biochemical activities and associated morphological changes, which may be considered a form of signal transduction leading to the construction of an organelle. Macropinocytosis may also convey information about the availability of extracellular nutrients to intracellular regulators of metabolism. Consistent with this idea, activation of the metabolic regulator mechanistic target of rapamycin complex-1 (mTORC1) in response to acute stimulation by growth factors and extracellular amino acids requires internalization of amino acids by macropinocytosis. This suggests that macropinocytosis is necessary for mTORC1-dependent growth of metazoan cells, both as a route for delivery of amino acids to sensors associated with lysosomes and as a platform for growth factor-dependent signalling to mTORC1 via phosphatidylinositol 3-kinase (PI3K) and the Akt pathway. Because the biochemical signals required for the construction of macropinosomes are also required for cell growth, and inhibition of macropinocytosis inhibits growth factor signalling to mTORC1, we propose that signalling by growth factor receptors is organized into stochastic, structure-dependent cascades of chemical reactions that both build a macropinosome and stimulate mTORC1. More generally, as discrete units of signal transduction, macropinosomes may be subject to feedback regulation by metabolism and cell dimensions. This article is part of the Theo Murphy meeting issue 'Macropinocytosis'.
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Affiliation(s)
- Joel A Swanson
- Department of Microbiology and Immunology, University of Michigan Medical School , Ann Arbor, MI 48109-5620 , USA
| | - Sei Yoshida
- Department of Microbiology and Immunology, University of Michigan Medical School , Ann Arbor, MI 48109-5620 , USA
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10
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Loh J, Chuang MC, Lin SS, Joseph J, Su YA, Hsieh TL, Chang YC, Liu AP, Liu YW. An acute decrease in plasma membrane tension induces macropinocytosis via PLD2 activation. J Cell Sci 2019; 132:jcs.232579. [PMID: 31391241 DOI: 10.1242/jcs.232579] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 07/29/2019] [Indexed: 12/13/2022] Open
Abstract
Internalization of macromolecules and membrane into cells through endocytosis is critical for cellular growth, signaling and plasma membrane (PM) tension homeostasis. Although endocytosis is responsive to both biochemical and physical stimuli, how physical cues modulate endocytic pathways is less understood. Contrary to the accumulating discoveries on the effects of increased PM tension on endocytosis, less is known about how a decrease of PM tension impacts on membrane trafficking. Here, we reveal that an acute decrease of PM tension results in phosphatidic acid (PA) production, F-actin and phosphatidylinositol (4,5)-bisphosphate [PI(4,5)P2]-enriched dorsal membrane ruffling and subsequent macropinocytosis in myoblasts. The PA production induced by decreased PM tension depends on phospholipase D2 (PLD2) activation via PLD2 nanodomain disintegration. Furthermore, the 'decreased PM tension-PLD2-macropinocytosis' pathway is prominent in myotubes, reflecting a potential mechanism of PM tension homeostasis upon intensive muscle stretching and relaxation. Together, we identify a new mechanotransduction pathway that converts an acute decrease in PM tension into PA production and then initiates macropinocytosis via actin and PI(4,5)P2-mediated processes.
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Affiliation(s)
- Julie Loh
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei 10002, Taiwan
| | - Mei-Chun Chuang
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei 10002, Taiwan
| | - Shan-Shan Lin
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei 10002, Taiwan
| | - Jophin Joseph
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - You-An Su
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei 10002, Taiwan
| | - Tsung-Lin Hsieh
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei 10002, Taiwan
| | - Yu-Chen Chang
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei 10002, Taiwan
| | - Allen P Liu
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Ya-Wen Liu
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei 10002, Taiwan .,Center of Precision Medicine, College of Medicine, National Taiwan University, Taipei 10002, Taiwan
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11
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Huang Q, Kahn CR, Altindis E. Viral Hormones: Expanding Dimensions in Endocrinology. Endocrinology 2019; 160:2165-2179. [PMID: 31310273 PMCID: PMC6736053 DOI: 10.1210/en.2019-00271] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 07/10/2019] [Indexed: 02/07/2023]
Abstract
Viruses have developed different mechanisms to manipulate their hosts, including the process of viral mimicry in which viruses express important host proteins. Until recently, examples of viral mimicry were limited to mimics of growth factors and immunomodulatory proteins. Using a comprehensive bioinformatics approach, we have shown that viruses possess the DNA/RNA with potential to encode 16 different peptides with high sequence similarity to human peptide hormones and metabolically important regulatory proteins. We have characterized one of these families, the viral insulin/IGF-1-like peptides (VILPs), which we identified in four members of the Iridoviridae family. VILPs can bind to human insulin and IGF-1 receptors and stimulate classic postreceptor signaling pathways. Moreover, VILPs can stimulate glucose uptake in vitro and in vivo and stimulate DNA synthesis. DNA sequences of some VILP-carrying viruses have been identified in the human enteric virome. In addition to VILPs, sequences with homology to 15 other peptide hormones or cytokines can be identified in viral DNA/RNA sequences, some with a very high identity to hormones. Recent data by others has identified a peptide that resembles and mimics α-melanocyte-stimulating hormone's anti-inflammatory effects in in vitro and in vivo models. Taken together, these studies reveal novel mechanisms of viral and bacterial pathogenesis in which the microbe can directly target or mimic the host endocrine system. These findings also introduce the concept of a system of microbial hormones that provides new insights into the evolution of peptide hormones, as well as potential new roles of microbial hormones in health and disease.
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Affiliation(s)
- Qian Huang
- Boston College Biology Department, Chestnut Hill, Massachusetts
| | - C Ronald Kahn
- Joslin Diabetes Center, Harvard Medical School, Boston, Massachusetts
| | - Emrah Altindis
- Boston College Biology Department, Chestnut Hill, Massachusetts
- Correspondence: Emrah Altindis, PhD, Boston College Biology Department, Higgins Hall 515, 140 Commonwealth Avenue, Chestnut Hill, Massachusetts 02467. E-mail:
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12
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Colin M, Delporte C, Janky R, Lechon AS, Renard G, Van Antwerpen P, Maltese WA, Mathieu V. Dysregulation of Macropinocytosis Processes in Glioblastomas May Be Exploited to Increase Intracellular Anti-Cancer Drug Levels: The Example of Temozolomide. Cancers (Basel) 2019; 11:cancers11030411. [PMID: 30909495 PMCID: PMC6468498 DOI: 10.3390/cancers11030411] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 03/15/2019] [Accepted: 03/20/2019] [Indexed: 12/16/2022] Open
Abstract
Macropinocytosis is a clathrin-independent endocytosis of extracellular fluid that may contribute to cancer aggressiveness through nutrient supply, recycling of plasma membrane and receptors, and exosome internalization. Macropinocytosis may be notably triggered by epidermal growth factor receptor (EGFR) and platelet-derived growth factor receptor (PDGFR), two well-known markers for glioblastoma aggressiveness. Therefore, we studied whether the expression of key actors of macropinocytosis is modified in human glioma datasets. Strong deregulation has been evidenced at the mRNA level according to the grade of the tumor, and 38 macropinocytosis-related gene signatures allowed discrimination of the glioblastoma (GBM) samples. Honokiol-induced vacuolization was then compared to vacquinol-1 and MOMIPP, two known macropinocytosis inducers. Despite high phase-contrast morphological similarities, honokiol-induced vacuoles appeared to originate from both endocytosis and ER. Also, acridine orange staining suggested differences in the macropinosomes’ fate: their fusion with lysosomes appeared very limited in 3-(5-methoxy -2-methyl-1H-indol-3-yl)-1-(4-pyridinyl)-2-propen-1-one (MOMIPP)-treated cells. Nevertheless, each of the compounds markedly increased temozolomide uptake by glioma cells, as evidenced by LC-MS. In conclusion, the observed deregulation of macropinocytosis in GBM makes them prone to respond to various compounds affecting their formation and/or intracellular fate. Considering that sustained macropinocytosis may also trigger cell death of both sensitive and resistant GBM cells, we propose to envisage macropinocytosis inducers in combination approaches to obtain dual benefits: increased drug uptake and additive/synergistic effects.
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Affiliation(s)
- Margaux Colin
- Department of Pharmacotherapy and Pharmaceuticals, Faculty of Pharmacy, Université Libre de Bruxelles (ULB), 1050 Brussels, Belgium.
| | - Cédric Delporte
- RD3-Pharmacognosy, Bioanalysis and Drug Discovery Unit and Analytical Platform, Faculty of Pharmacy, Université libre de Bruxelles (ULB), 1050 Brussels, Belgium.
| | | | - Anne-Sophie Lechon
- Department of Pharmacotherapy and Pharmaceuticals, Faculty of Pharmacy, Université Libre de Bruxelles (ULB), 1050 Brussels, Belgium.
| | - Gwendoline Renard
- Department of Pharmacotherapy and Pharmaceuticals, Faculty of Pharmacy, Université Libre de Bruxelles (ULB), 1050 Brussels, Belgium.
| | - Pierre Van Antwerpen
- RD3-Pharmacognosy, Bioanalysis and Drug Discovery Unit and Analytical Platform, Faculty of Pharmacy, Université libre de Bruxelles (ULB), 1050 Brussels, Belgium.
| | - William A Maltese
- Department of Cancer Biology, University of Toledo College of Medicine, Toledo, OH 43614, USA.
| | - Véronique Mathieu
- Department of Pharmacotherapy and Pharmaceuticals, Faculty of Pharmacy, Université Libre de Bruxelles (ULB), 1050 Brussels, Belgium.
- ULB Cancer Research Center, Université libre de Bruxelles (ULB), 1050 Bruxelles, Belgium.
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13
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Increasing Diversity of Biological Membrane Fission Mechanisms. Trends Cell Biol 2018; 28:274-286. [DOI: 10.1016/j.tcb.2017.12.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 12/06/2017] [Accepted: 12/12/2017] [Indexed: 12/19/2022]
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14
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Delpeut S, Sisson G, Black KM, Richardson CD. Measles Virus Enters Breast and Colon Cancer Cell Lines through a PVRL4-Mediated Macropinocytosis Pathway. J Virol 2017; 91:e02191-16. [PMID: 28250131 PMCID: PMC5411587 DOI: 10.1128/jvi.02191-16] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2016] [Accepted: 02/21/2017] [Indexed: 12/20/2022] Open
Abstract
Measles virus (MeV) is a member of the family Paramixoviridae that causes a highly contagious respiratory disease but has emerged as a promising oncolytic platform. Previous studies of MeV entry focused on the identification of cellular receptors. However, the endocytic and trafficking pathways utilized during MeV entry remain poorly described. The contribution of each endocytic pathway has been examined in cells that express the MeV receptors SLAM (signaling lymphocyte-activating molecule) and PVRL4 (poliovirus receptor-like 4) (nectin-4). Recombinant MeVs expressing either firefly luciferase or green fluorescent protein together with a variety of inhibitors were used. The results showed that MeV uptake was dynamin independent in the Vero.hPVRL4, Vero.hSLAM, and PVRL4-positive MCF7 breast cancer cell lines. However, MeV infection was blocked by 5-(N-ethyl-N-propyl)amiloride (EIPA), the hallmark inhibitor of macropinocytosis, as well as inhibitors of actin polymerization. By using phalloidin staining, MeV entry was shown to induce actin rearrangements and the formation of membrane ruffles accompanied by transient elevated fluid uptake. Small interfering RNA (siRNA) knockdown of p21-activated kinase 1 (PAK1) demonstrated that MeV enters both Vero.hPVRL4 and Vero.hSLAM cells in a PAK1-independent manner using a macropinocytosis-like pathway. In contrast, MeV entry into MCF7 human breast cancer cells relied upon Rac1 and its effector PAK1 through a PVRL4-mediated macropinocytosis pathway. MeV entry into DLD-1 colon and HTB-20 breast cancer cells also appeared to use the same pathway. Overall, these findings provide new insight into the life cycle of MeV, which could lead to therapies that block virus entry or methods that improve the uptake of MeV by cancer cells during oncolytic therapy.IMPORTANCE In the past decades, measles virus (MeV) has emerged as a promising oncolytic platform. Previous studies concerning MeV entry focused mainly on the identification of putative receptors for MeV. Nectin-4 (PVRL4) was recently identified as the epithelial cell receptor for MeV. However, the specific endocytic and trafficking pathways utilized during MeV infections are poorly documented. In this study, we demonstrated that MeV enters host cells via a dynamin-independent and actin-dependent endocytic pathway. Moreover, we show that MeV gains entry into MCF7, DLD-1, and HTB-20 cancer cells through a PVRL4-mediated macropinocytosis pathway and identified the typical cellular GTPase and kinase involved. Our findings provide new insight into the life cycle of MeV, which may lead to the development of therapies that block the entry of the virus into the host cell or alternatively promote the uptake of oncolytic MeV into cancer cells.
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Affiliation(s)
- Sebastien Delpeut
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada
- Canadian Centre for Vaccinology, IWK Health Centre, Goldbloom Pavilion, Halifax, Nova Scotia, Canada
| | - Gary Sisson
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Karen M Black
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Christopher D Richardson
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada
- Canadian Centre for Vaccinology, IWK Health Centre, Goldbloom Pavilion, Halifax, Nova Scotia, Canada
- Department of Pediatrics, Dalhousie University, Halifax, Nova Scotia, Canada
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15
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HIRAI CHIHOKO, BADAWY SHAYMAAMOHAMEDMOHAMED, ZHANG LIFANG, OKADA TARO, KAJIMOTO TAKETOSHI, NAKAMURA SHUNICHI. Phospholipase D is Dispensable for Epidermal Growth Factor-Induced Chemotaxis. THE KOBE JOURNAL OF MEDICAL SCIENCES 2017; 62:E162-E167. [PMID: 28490713 PMCID: PMC5436530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 12/26/2016] [Indexed: 06/07/2023]
Abstract
α-Synuclein (α-Syn) is implicated in several neurodegenerative disorders, including Parkinson's disease, known collectively as the synucleinopathies. α-Syn is known to be secreted from the cells and may contribute to the progression of the disease. Although extracellular α-Syn is shown to impair platelet-derived growth factor-induced chemotaxis, molecular mechanism of α-Syn-induced motility failure remains elusive. Here we have aimed at phospholipase D (PLD) as a potential target for α-Syn and examined the involvement of this enzyme in α-Syn action. Indeed, extracellular α-Syn caused inhibition of agonist-induced PLD activation. However, inhibition of hydrolytic activity of PLD by 1-butanol treatment showed little or no effect on agonist-induced chemotaxis. These results suggest that some signaling pathways other than PLD may be involved in α-Syn-induced inhibition of chemotaxis.
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16
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Pagliuso A, Valente C, Giordano LL, Filograna A, Li G, Circolo D, Turacchio G, Marzullo VM, Mandrich L, Zhukovsky MA, Formiggini F, Polishchuk RS, Corda D, Luini A. Golgi membrane fission requires the CtBP1-S/BARS-induced activation of lysophosphatidic acid acyltransferase δ. Nat Commun 2016; 7:12148. [PMID: 27401954 PMCID: PMC4945875 DOI: 10.1038/ncomms12148] [Citation(s) in RCA: 214] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 06/03/2016] [Indexed: 11/25/2022] Open
Abstract
Membrane fission is an essential cellular process by which continuous membranes split into separate parts. We have previously identified CtBP1-S/BARS (BARS) as a key component of a protein complex that is required for fission of several endomembranes, including basolateral post-Golgi transport carriers. Assembly of this complex occurs at the Golgi apparatus, where BARS binds to the phosphoinositide kinase PI4KIIIβ through a 14-3-3γ dimer, as well as to ARF and the PKD and PAK kinases. We now report that, when incorporated into this complex, BARS binds to and activates a trans-Golgi lysophosphatidic acid (LPA) acyltransferase type δ (LPAATδ) that converts LPA into phosphatidic acid (PA); and that this reaction is essential for fission of the carriers. LPA and PA have unique biophysical properties, and their interconversion might facilitate the fission process either directly or indirectly (via recruitment of proteins that bind to PA, including BARS itself).
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Affiliation(s)
- Alessandro Pagliuso
- Institute of Protein Biochemistry, National Research Council, Via Pietro Castellino 111, 80131 Naples, Italy
- Telethon Institute of Genetics and Medicine (TIGEM), Via Campi Flegrei 34, Pozzuoli 80078, Italy
| | - Carmen Valente
- Institute of Protein Biochemistry, National Research Council, Via Pietro Castellino 111, 80131 Naples, Italy
| | - Lucia Laura Giordano
- Institute of Protein Biochemistry, National Research Council, Via Pietro Castellino 111, 80131 Naples, Italy
| | - Angela Filograna
- Institute of Protein Biochemistry, National Research Council, Via Pietro Castellino 111, 80131 Naples, Italy
| | - Guiling Li
- Institute of Protein Biochemistry, National Research Council, Via Pietro Castellino 111, 80131 Naples, Italy
| | - Diego Circolo
- Institute of Protein Biochemistry, National Research Council, Via Pietro Castellino 111, 80131 Naples, Italy
| | - Gabriele Turacchio
- Institute of Protein Biochemistry, National Research Council, Via Pietro Castellino 111, 80131 Naples, Italy
| | - Vincenzo Manuel Marzullo
- IRCCS SDN Istituto di Ricerca Diagnostica e Nucleare, Via Emanuele Gianturco 113, 80143 Naples, Italy
| | - Luigi Mandrich
- Institute of Protein Biochemistry, National Research Council, Via Pietro Castellino 111, 80131 Naples, Italy
| | - Mikhail A. Zhukovsky
- Institute of Protein Biochemistry, National Research Council, Via Pietro Castellino 111, 80131 Naples, Italy
| | - Fabio Formiggini
- Italian Institute of Technology, Centre for Advanced Biomaterials for Health Care at CRIB, Largo Barsanti e Matteucci 53, Naples 80125, Italy
| | - Roman S. Polishchuk
- Telethon Institute of Genetics and Medicine (TIGEM), Via Campi Flegrei 34, Pozzuoli 80078, Italy
| | - Daniela Corda
- Institute of Protein Biochemistry, National Research Council, Via Pietro Castellino 111, 80131 Naples, Italy
| | - Alberto Luini
- Institute of Protein Biochemistry, National Research Council, Via Pietro Castellino 111, 80131 Naples, Italy
- IRCCS SDN Istituto di Ricerca Diagnostica e Nucleare, Via Emanuele Gianturco 113, 80143 Naples, Italy
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17
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Vodicka P, Mo S, Tousley A, Green KM, Sapp E, Iuliano M, Sadri-Vakili G, Shaffer SA, Aronin N, DiFiglia M, Kegel-Gleason KB. Mass Spectrometry Analysis of Wild-Type and Knock-in Q140/Q140 Huntington's Disease Mouse Brains Reveals Changes in Glycerophospholipids Including Alterations in Phosphatidic Acid and Lyso-Phosphatidic Acid. J Huntingtons Dis 2016; 4:187-201. [PMID: 26397899 DOI: 10.3233/jhd-150149] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND Huntington's disease (HD) is a neurodegenerative disease caused by a CAG expansion in the HD gene, which encodes the protein Huntingtin. Huntingtin associates with membranes and can interact directly with glycerophospholipids in membranes. OBJECTIVE We analyzed glycerophospholipid profiles from brains of 11 month old wild-type (WT) and Q140/Q140 HD knock-in mice to assess potential changes in glycerophospholipid metabolism. METHODS Polar lipids from cerebellum, cortex, and striatum were extracted and analyzed by liquid chromatography and negative ion electrospray tandem mass spectrometry analysis (LC-MS/MS). Gene products involved in polar lipid metabolism were studied using western blotting, immuno-electron microscopy and qPCR. RESULTS Significant changes in numerous species of glycerophosphate (phosphatidic acid, PA) were found in striatum, cerebellum and cortex from Q140/Q140 HD mice compared to WT mice at 11 months. Changes in specific species could also be detected for other glycerophospholipids. Increases in species of lyso-PA (LPA) were measured in striatum of Q140/Q140 HD mice compared to WT. Protein levels for c-terminal binding protein 1 (CtBP1), a regulator of PA biosynthesis, were reduced in striatal synaptosomes from HD mice compared to wild-type at 6 and 12 months. Immunoreactivity for CtBP1 was detected on membranes of synaptic vesicles in striatal axon terminals in the globus pallidus. CONCLUSIONS These novel results identify a potential site of molecular pathology caused by mutant Huntingtin that may impart early changes in HD.
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Affiliation(s)
- Petr Vodicka
- Department of Neurology, Massachusetts General Hospital, Charlestown, MA, USA
| | - Shunyan Mo
- Proteomics and Mass Spectrometry Facility and Department of Biochemistry and Molecular Pharmacology, UMASS Medical School, Worcester, MA, USA
| | - Adelaide Tousley
- Department of Neurology, Massachusetts General Hospital, Charlestown, MA, USA
| | - Karin M Green
- Proteomics and Mass Spectrometry Facility and Department of Biochemistry and Molecular Pharmacology, UMASS Medical School, Worcester, MA, USA
| | - Ellen Sapp
- Department of Neurology, Massachusetts General Hospital, Charlestown, MA, USA
| | - Maria Iuliano
- Department of Neurology, Massachusetts General Hospital, Charlestown, MA, USA
| | | | - Scott A Shaffer
- Proteomics and Mass Spectrometry Facility and Department of Biochemistry and Molecular Pharmacology, UMASS Medical School, Worcester, MA, USA
| | - Neil Aronin
- Departments of Medicine and Cell and Developmental Biology, UMASS Medical School, Worcester, MA, USA
| | - Marian DiFiglia
- Department of Neurology, Massachusetts General Hospital, Charlestown, MA, USA
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18
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Bruntz RC, Lindsley CW, Brown HA. Phospholipase D signaling pathways and phosphatidic acid as therapeutic targets in cancer. Pharmacol Rev 2015; 66:1033-79. [PMID: 25244928 DOI: 10.1124/pr.114.009217] [Citation(s) in RCA: 161] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Phospholipase D is a ubiquitous class of enzymes that generates phosphatidic acid as an intracellular signaling species. The phospholipase D superfamily plays a central role in a variety of functions in prokaryotes, viruses, yeast, fungi, plants, and eukaryotic species. In mammalian cells, the pathways modulating catalytic activity involve a variety of cellular signaling components, including G protein-coupled receptors, receptor tyrosine kinases, polyphosphatidylinositol lipids, Ras/Rho/ADP-ribosylation factor GTPases, and conventional isoforms of protein kinase C, among others. Recent findings have shown that phosphatidic acid generated by phospholipase D plays roles in numerous essential cellular functions, such as vesicular trafficking, exocytosis, autophagy, regulation of cellular metabolism, and tumorigenesis. Many of these cellular events are modulated by the actions of phosphatidic acid, and identification of two targets (mammalian target of rapamycin and Akt kinase) has especially highlighted a role for phospholipase D in the regulation of cellular metabolism. Phospholipase D is a regulator of intercellular signaling and metabolic pathways, particularly in cells that are under stress conditions. This review provides a comprehensive overview of the regulation of phospholipase D activity and its modulation of cellular signaling pathways and functions.
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Affiliation(s)
- Ronald C Bruntz
- Department of Pharmacology (R.C.B., C.W.L., H.A.B.) and Vanderbilt Center for Neuroscience Drug Discovery (C.W.L.), Vanderbilt University Medical Center; Department of Chemistry, Vanderbilt Institute of Chemical Biology (C.W.L., H.A.B.); Vanderbilt Specialized Chemistry for Accelerated Probe Development (C.W.L.); and Department of Biochemistry, Vanderbilt-Ingram Cancer Center (H.A.B.), Vanderbilt University, Nashville, Tennessee
| | - Craig W Lindsley
- Department of Pharmacology (R.C.B., C.W.L., H.A.B.) and Vanderbilt Center for Neuroscience Drug Discovery (C.W.L.), Vanderbilt University Medical Center; Department of Chemistry, Vanderbilt Institute of Chemical Biology (C.W.L., H.A.B.); Vanderbilt Specialized Chemistry for Accelerated Probe Development (C.W.L.); and Department of Biochemistry, Vanderbilt-Ingram Cancer Center (H.A.B.), Vanderbilt University, Nashville, Tennessee
| | - H Alex Brown
- Department of Pharmacology (R.C.B., C.W.L., H.A.B.) and Vanderbilt Center for Neuroscience Drug Discovery (C.W.L.), Vanderbilt University Medical Center; Department of Chemistry, Vanderbilt Institute of Chemical Biology (C.W.L., H.A.B.); Vanderbilt Specialized Chemistry for Accelerated Probe Development (C.W.L.); and Department of Biochemistry, Vanderbilt-Ingram Cancer Center (H.A.B.), Vanderbilt University, Nashville, Tennessee
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19
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Egami Y, Taguchi T, Maekawa M, Arai H, Araki N. Small GTPases and phosphoinositides in the regulatory mechanisms of macropinosome formation and maturation. Front Physiol 2014; 5:374. [PMID: 25324782 PMCID: PMC4179697 DOI: 10.3389/fphys.2014.00374] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Accepted: 09/10/2014] [Indexed: 12/26/2022] Open
Abstract
Macropinosome formation requires the sequential activation of numerous signaling pathways that coordinate the actin-driven formation of plasma membrane protrusions (ruffles) and circular ruffles (macropinocytic cups), followed by the closure of these macropinocytic cups into macropinosomes. In the process of macropinosome formation, localized productions of phosphoinositides such as PI(4,5)P2 and PI(3,4,5)P3 spatiotemporally orchestrate actin polymerization and rearrangement through recruiting and activating a variety of actin-associated proteins. In addition, the sequential activation of small GTPases, which are known to be master regulators of the actin cytoskeleton, plays a pivotal role in parallel with phosphoinositides. To complete macropinosome formation, phosphoinositide breakdown and Rho GTPase deactivation must occur in appropriate timings. After the nascent macropinosomes are formed, phosphoinositides and several Rab GTPases control macropinosome maturation by regulating vesicle trafficking and membrane fusion. In this review, we summarize recent advances in our understanding of the critical functions of phosphoinositide metabolism and small GTPases in association with their downstream effectors in macropinocytosis.
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Affiliation(s)
- Youhei Egami
- Department of Histology and Cell Biology, School of Medicine, Kagawa University Miki, Japan
| | - Tomohiko Taguchi
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, University of Tokyo Tokyo, Japan ; Pathological Cell Biology Laboratory, Graduate School of Pharmaceutical Sciences, University of Tokyo Tokyo, Japan
| | - Masashi Maekawa
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, University of Tokyo Tokyo, Japan ; Keenan Research Centre, Li Ka Shing Knowledge Institute, St. Michael's Hospital Toronto, ON, Canada
| | - Hiroyuki Arai
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, University of Tokyo Tokyo, Japan ; Pathological Cell Biology Laboratory, Graduate School of Pharmaceutical Sciences, University of Tokyo Tokyo, Japan
| | - Nobukazu Araki
- Department of Histology and Cell Biology, School of Medicine, Kagawa University Miki, Japan
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20
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Entry of a novel marine DNA virus, Singapore grouper iridovirus, into host cells occurs via clathrin-mediated endocytosis and macropinocytosis in a pH-dependent manner. J Virol 2014; 88:13047-63. [PMID: 25165116 DOI: 10.1128/jvi.01744-14] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
UNLABELLED Iridoviruses are nucleocytoplasmic DNA viruses which cause great economic losses in the aquaculture industry but also show significant threat to global biodiversity. However, a lack of host cells has resulted in poor progress in clarifying iridovirus behavior. We investigated the crucial events during virus entry using a combination of single-virus tracking and biochemical assays, based on the established virus-cell infection model for Singapore grouper iridovirus (SGIV). SGIV infection in host cells was strongly inhibited when cells were pretreated with drugs blocking clathrin-mediated endocytosis, including sucrose and chlorpromazine. Inhibition of key regulators of macropinocytosis, including Na(+)/H(+) exchanger, Rac1 GTPase, p21-activated kinase 1 (PAK1), protein kinase C (PKC), and myosin II, significantly reduced SGIV uptake. Cy5-labeled SGIV particles were observed to colocalize with clathrin and macropinosomes. In contrast, disruption of cellular cholesterol by methyl-β-cyclodextrin and nystatin had no effect on virus infection, suggesting that SGIV entered grouper cells via the clathrin-mediated endocytic pathway and macropinocytosis but not via caveola-dependent endocytosis. Furthermore, inhibitors of endosome acidification such as chloroquine and bafilomycin A1 blocked virus infection, indicating that SGIV entered cells in a pH-dependent manner. In addition, SGIV particles were observed to be transported along both microtubules and actin filaments, and intracellular SGIV motility was remarkably impaired by depolymerization of microtubules or actin filaments. The results of this study for the first time demonstrate that not only the clathrin-dependent pathway but also macropinocytosis are involved in fish DNA enveloped virus entry, thus providing a convenient tactic for exploring the life cycle of DNA viruses. IMPORTANCE Virus entry into host cells is critically important for initiating infections and is usually recognized as an ideal target for the design of antiviral strategies. Iridoviruses are large DNA viruses which cause serious threats to ecological diversity and the aquaculture industry worldwide. However, the current understanding of iridovirus entry is limited and controversial. Singapore grouper iridovirus (SGIV) is a novel marine fish DNA virus which belongs to genus Ranavirus, family Iridoviridae. Here, using single-virus tracking technology in combination with biochemical assays, we investigated the crucial events during SGIV entry and demonstrated that SGIV entered grouper cells via the clathrin-mediated endocytic pathway in a pH-dependent manner but not via caveola-dependent endocytosis. Furthermore, we propose for the first time that macropinocytosis is involved in iridovirus entry. Together, this work not only contributes greatly to understating iridovirus pathogenesis but also provides an ideal model for exploring the behavior of DNA viruses in living cells.
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21
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Patanè S. Ebola: is there a hope from treatment with cardiovascular drugs? Int J Cardiol 2014; 177:524-6. [PMID: 25205490 DOI: 10.1016/j.ijcard.2014.08.114] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Accepted: 08/17/2014] [Indexed: 12/24/2022]
Affiliation(s)
- Salvatore Patanè
- Cardiologia Ospedale San Vincenzo - Taormina (Me) Azienda Sanitaria Provinciale di Messina, Contrada Sirina, 98039 Taormina (Messina), Italy. patane-@libero.it
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22
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Sakurai T, Woolls MJ, Jin SW, Murakami M, Simons M. Inter-cellular exchange of cellular components via VE-cadherin-dependent trans-endocytosis. PLoS One 2014; 9:e90736. [PMID: 24603875 PMCID: PMC3946293 DOI: 10.1371/journal.pone.0090736] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Accepted: 02/05/2014] [Indexed: 11/18/2022] Open
Abstract
Cell-cell communications typically involve receptor-mediated signaling initiated by soluble or cell-bound ligands. Here, we report a unique mode of endocytosis: proteins originating from cell-cell junctions and cytosolic cellular components from the neighboring cell are internalized, leading to direct exchange of cellular components between two adjacent endothelial cells. VE-cadherins form transcellular bridges between two endothelial cells that are the basis of adherence junctions. At such adherens junction sites, we observed the movement of the entire VE-cadherin molecule from one endothelial cell into the other with junctional and cytoplasmic components. This phenomenon, here termed trans-endocytosis, requires the establishment of a VE-cadherin homodimer in trans with internalization proceeding in a Rac1-, and actomyosin-dependent manner. Importantly, the trans-endocytosis is not dependent on any known endocytic pathway including clathrin-dependent endocytosis, macropinocytosis or phagocytosis. This novel form of cell-cell communications, leading to a direct exchange of cellular components, was observed in 2D and 3D-cultured endothelial cells as well as in the developing zebrafish vasculature.
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Affiliation(s)
- Takashi Sakurai
- Yale Cardiovascular Research Center and Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, United States of America
- * E-mail:
| | - Melissa J. Woolls
- Yale Cardiovascular Research Center and Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - Suk-Won Jin
- Yale Cardiovascular Research Center and Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - Masahiro Murakami
- Yale Cardiovascular Research Center and Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - Michael Simons
- Yale Cardiovascular Research Center and Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, United States of America
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut, United States of America
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23
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Sequential breakdown of 3-phosphorylated phosphoinositides is essential for the completion of macropinocytosis. Proc Natl Acad Sci U S A 2014; 111:E978-87. [PMID: 24591580 DOI: 10.1073/pnas.1311029111] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Macropinocytosis is a highly conserved endocytic process by which extracellular fluid and solutes are internalized into cells. Macropinocytosis starts with the formation of membrane ruffles at the plasma membrane and ends with their closure. The transient and sequential emergence of phosphoinositides PI(3,4,5)P3 and PI(3,4)P2 in the membrane ruffles is essential for macropinocytosis. By making use of information in the Caenorhabditis elegans mutants defective in fluid-phase endocytosis, we found that mammalian phosphoinositide phosphatase MTMR6 that dephosphorylates PI(3)P to PI, and its binding partner MTMR9, are required for macropinocytosis. INPP4B, which dephosphorylates PI(3,4)P2 to PI(3)P, was also found to be essential for macropinocytosis. These phosphatases operate after the formation of membrane ruffles to complete macropinocytosis. Finally, we showed that KCa3.1, a Ca(2+)-activated K(+) channel that is activated by PI(3)P, is required for macropinocytosis. We propose that the sequential breakdown of PI(3,4,5)P3 → PI(3,4)P2 → PI(3)P → PI controls macropinocytosis through specific effectors of the intermediate phosphoinositides.
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24
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Nakamura K, Yamanouchi K, Nishihara M. Secreted protein acidic and rich in cysteine internalization and its age-related alterations in skeletal muscle progenitor cells. Aging Cell 2014; 13:175-84. [PMID: 24245505 PMCID: PMC4326877 DOI: 10.1111/acel.12168] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/27/2013] [Indexed: 01/06/2023] Open
Abstract
Aging causes phenotypic changes in skeletal muscle progenitor cells (Skm-PCs), such as reduced myogenesis and increased adipogenesis due to alterations in their environment or niche. Secreted protein acidic and rich in cysteine (SPARC), which is secreted into the niche of Skm-PCs, inhibits adipogenesis and promotes myogenesis. We have previously reported that Skm-PC responsiveness to SPARC declines with age, although the mechanism underlying this decline is unknown. In this study, we found that SPARC is internalized by Skm-PCs and that this uptake increases with age. Internalization is dependent on integrin-α5, a cell surface SPARC-binding molecule, and clathrin-mediated endocytosis. We also demonstrated that internalized SPARC is transported to Rab7-positive endosomes. Skm-PCs from old rats exhibited increased clathrin expression and decreased Rab7 expression exclusively in MyoD-negative cells. In loss-of-function analyses, clathrin knockdown increased the anti-adipogenic effect of SPARC, whereas Rab7 knockdown reduced it, indicating that alterations in SPARC internalization may mediate the age-related decline in its anti-adipogenic effect. These results provide insights into age-related SPARC resistance in Skm-PCs, which may lead to sarcopenia.
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Affiliation(s)
- Katsuyuki Nakamura
- Department of Veterinary Physiology; Graduate School of Agricultural and Life Sciences; The University of Tokyo; 1-1-1 Yayoi Bunkyo-ku Tokyo 113-8657 Japan
| | - Keitaro Yamanouchi
- Department of Veterinary Physiology; Graduate School of Agricultural and Life Sciences; The University of Tokyo; 1-1-1 Yayoi Bunkyo-ku Tokyo 113-8657 Japan
| | - Masugi Nishihara
- Department of Veterinary Physiology; Graduate School of Agricultural and Life Sciences; The University of Tokyo; 1-1-1 Yayoi Bunkyo-ku Tokyo 113-8657 Japan
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25
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Commisso C, Flinn RJ, Bar-Sagi D. Determining the macropinocytic index of cells through a quantitative image-based assay. Nat Protoc 2014; 9:182-92. [PMID: 24385148 DOI: 10.1038/nprot.2014.004] [Citation(s) in RCA: 150] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Macropinocytosis serves as an internalization pathway for extracellular fluid and its contents. Macropinocytosis is upregulated in oncogene-expressing cells and, recently, we have revealed a functional role for macropinocytosis in fueling cancer cell growth through the internalization of extracellular albumin, which is degraded into a usable source of intracellular amino acids. Assessing macropinocytosis has been challenging in the past because of the lack of reliable assays capable of quantitatively measuring this uptake mechanism. Here we describe a protocol for visualizing and quantifying the extent of macropinocytosis in cells both in culture and growing in vivo as tumor xenografts. By using this approach, the 'macropinocytic index' of a particular cell line or subcutaneous tumor can be ascertained within 1-2 d. The protocol can be carried out with multiple samples in parallel and can be easily adapted for a variety of cell types and xenograft or allograft mouse models.
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Affiliation(s)
- Cosimo Commisso
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York, USA
| | - Rory J Flinn
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York, USA
| | - Dafna Bar-Sagi
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York, USA
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26
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Tan J, Brill JA. Cinderella story: PI4P goes from precursor to key signaling molecule. Crit Rev Biochem Mol Biol 2013; 49:33-58. [PMID: 24219382 DOI: 10.3109/10409238.2013.853024] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Phosphatidylinositol lipids are signaling molecules involved in nearly all aspects of cellular regulation. Production of phosphatidylinositol 4-phosphate (PI4P) has long been recognized as one of the first steps in generating poly-phosphatidylinositol phosphates involved in actin organization, cell migration, and signal transduction. In addition, progress over the last decade has brought to light independent roles for PI4P in membrane trafficking and lipid homeostasis. Here, we describe recent advances that reveal the breadth of processes regulated by PI4P, the spectrum of PI4P effectors, and the mechanisms of spatiotemporal control that coordinate crosstalk between PI4P and cellular signaling pathways.
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Affiliation(s)
- Julie Tan
- Department of Molecular Genetics, University of Toronto , Toronto, Ontario , Canada and
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Components of the CtBP1/BARS-dependent fission machinery. Histochem Cell Biol 2013; 140:407-21. [PMID: 23996193 DOI: 10.1007/s00418-013-1138-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/20/2013] [Indexed: 01/12/2023]
Abstract
The brefeldin A ADP-ribosylated substrate, a member of the C-terminal-binding protein family that is referred to as CtBP1/BARS, is a dual-function protein that acts as a transcriptional co-repressor in the nucleus and as an inducer of membrane fission in the cytoplasm. In this review, we first discuss the mechanisms that enable CtBP1/BARS to shift between the nuclear transcriptional co-repressor and the cytosolic fission-inducing activities. Then, we focus on the role of CtBP1/BARS in membrane fission. CtBP1/BARS controls several fission events including macropinocytosis, fluid-phase endocytosis, COPI-coated vesicle formation, basolaterally directed post-Golgi carrier formation, and Golgi partitioning in mitosis. We report on recent advances in our understanding of the CtBP1/BARS membrane fission machineries that operate at the trans-side and at the cis-side of the Golgi complex. Specifically, we discuss how these machineries are assembled and regulated, and how they operate in the formation of the basolaterally directed post-Golgi carriers.
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C-Terminal Binding Protein: A Molecular Link between Metabolic Imbalance and Epigenetic Regulation in Breast Cancer. Int J Cell Biol 2013; 2013:647975. [PMID: 23762064 PMCID: PMC3671672 DOI: 10.1155/2013/647975] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Revised: 04/14/2013] [Accepted: 04/15/2013] [Indexed: 12/21/2022] Open
Abstract
The prevalence of obesity has given rise to significant global concerns as numerous population-based studies demonstrate an incontrovertible association between obesity and breast cancer. Mechanisms proposed to account for this linkage include exaggerated levels of carbohydrate substrates, elevated levels of circulating mitogenic hormones, and inflammatory cytokines that impinge on epithelial programming in many tissues. Moreover, recently many scientists have rediscovered the observation, first described by Otto Warburg nearly a century ago, that most cancer cells undergo a dramatic metabolic shift in energy utilization and expenditure that fuels and supports the cellular expansion associated with malignant proliferation. This shift in substrate oxidation comes at the cost of sharp changes in the levels of the high energy intermediate, nicotinamide adenine dinucleotide (NADH). In this review, we discuss a novel example of how shifts in the concentration and flux of substrates metabolized and generated during carbohydrate metabolism represent components of a signaling network that can influence epigenetic regulatory events in the nucleus. We refer to this regulatory process as "metabolic transduction" and describe how the C-terminal binding protein (CtBP) family of NADH-dependent nuclear regulators represents a primary example of how cellular metabolic status can influence epigenetic control of cellular function and fate.
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Sanematsu F, Nishikimi A, Watanabe M, Hongu T, Tanaka Y, Kanaho Y, Côté JF, Fukui Y. Phosphatidic acid-dependent recruitment and function of the Rac activator DOCK1 during dorsal ruffle formation. J Biol Chem 2013; 288:8092-8100. [PMID: 23362269 DOI: 10.1074/jbc.m112.410423] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Activation of receptor tyrosine kinases leads to the formation of two different types of plasma membrane structures: peripheral ruffles and dorsal ruffles. Although the formation of both ruffle types requires activation of the small GTPase Rac, the difference in kinetics suggests that a distinct regulatory mechanism operates for their ruffle formation. DOCK1 and DOCK5 are atypical Rac activators and are both expressed in mouse embryonic fibroblasts (MEFs). We found that although PDGF-induced Rac activation and peripheral ruffle formation were coordinately regulated by DOCK1 and DOCK5 in MEFs, DOCK1 deficiency alone impaired dorsal ruffle formation in MEFs. Unlike DOCK5, DOCK1 bound to phosphatidic acid (PA) through the C-terminal polybasic amino acid cluster and was localized to dorsal ruffles. When this interaction was blocked, PDGF-induced dorsal ruffle formation was severely impaired. In addition, we show that phospholipase D, an enzyme that catalyzes PA synthesis, is required for PDGF-induced dorsal, but not peripheral, ruffle formation. These results indicate that the phospholipase D-PA axis selectively controls dorsal ruffle formation by regulating DOCK1 localization.
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Affiliation(s)
- Fumiyuki Sanematsu
- Division of Immunogenetics, Department of Immunobiology and Neuroscience, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan; Research Center for Advanced Immunology, Kyushu University, Fukuoka 812-8582, Japan; Japan Science and Technology Agency, Core Research for Evolutional Science and Technology, Tokyo 102-0075, Japan
| | - Akihiko Nishikimi
- Division of Immunogenetics, Department of Immunobiology and Neuroscience, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan; Research Center for Advanced Immunology, Kyushu University, Fukuoka 812-8582, Japan; Japan Science and Technology Agency, Core Research for Evolutional Science and Technology, Tokyo 102-0075, Japan
| | - Mayuki Watanabe
- Division of Immunogenetics, Department of Immunobiology and Neuroscience, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan; Japan Science and Technology Agency, Core Research for Evolutional Science and Technology, Tokyo 102-0075, Japan
| | - Tsunaki Hongu
- Graduate School of Comprehensive Human Sciences, Institute of Basic Medical Sciences, University of Tsukuba, Ibaraki 305-8575, Japan
| | - Yoshihiko Tanaka
- Division of Immunogenetics, Department of Immunobiology and Neuroscience, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan; Research Center for Advanced Immunology, Kyushu University, Fukuoka 812-8582, Japan; Japan Science and Technology Agency, Core Research for Evolutional Science and Technology, Tokyo 102-0075, Japan
| | - Yasunori Kanaho
- Graduate School of Comprehensive Human Sciences, Institute of Basic Medical Sciences, University of Tsukuba, Ibaraki 305-8575, Japan
| | - Jean-François Côté
- Institut de Recherches Cliniques de Montréal, Université de Montréal, Montréal, Québec H2W 1R7, Canada
| | - Yoshinori Fukui
- Division of Immunogenetics, Department of Immunobiology and Neuroscience, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan; Research Center for Advanced Immunology, Kyushu University, Fukuoka 812-8582, Japan; Japan Science and Technology Agency, Core Research for Evolutional Science and Technology, Tokyo 102-0075, Japan.
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Bohdanowicz M, Grinstein S. Role of Phospholipids in Endocytosis, Phagocytosis, and Macropinocytosis. Physiol Rev 2013; 93:69-106. [DOI: 10.1152/physrev.00002.2012] [Citation(s) in RCA: 198] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Endocytosis, phagocytosis, and macropinocytosis are fundamental processes that enable cells to sample their environment, eliminate pathogens and apoptotic bodies, and regulate the expression of surface components. While a great deal of effort has been devoted over many years to understanding the proteins involved in these processes, the important contribution of phospholipids has only recently been appreciated. This review is an attempt to collate and analyze the rapidly emerging evidence documenting the role of phospholipids in clathrin-mediated endocytosis, phagocytosis, and macropinocytosis. A primer on phospholipid biosynthesis, catabolism, subcellular distribution, and transport is presented initially, for reference, together with general considerations of the effects of phospholipids on membrane curvature and charge. This is followed by a detailed analysis of the critical functions of phospholipids in the internalization processes and in the maturation of the resulting vesicles and vacuoles as they progress along the endo-lysosomal pathway.
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Affiliation(s)
- Michal Bohdanowicz
- Division of Cell Biology, Hospital for Sick Children, and Institute of Medical Sciences, University of Toronto, Toronto, Canada
| | - Sergio Grinstein
- Division of Cell Biology, Hospital for Sick Children, and Institute of Medical Sciences, University of Toronto, Toronto, Canada
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Barrias ES, Reignault LC, De Souza W, Carvalho TMU. Trypanosoma cruzi uses macropinocytosis as an additional entry pathway into mammalian host cell. Microbes Infect 2012; 14:1340-51. [PMID: 23010292 DOI: 10.1016/j.micinf.2012.08.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2011] [Revised: 06/26/2012] [Accepted: 08/16/2012] [Indexed: 12/25/2022]
Abstract
Several intracellular pathogens are internalized by host cells via multiple endocytic pathways. It is no different with Trypanosoma cruzi. Evidences indicate that T. cruzi entry may occur by endocytosis/phagocytosis or by an active manner. Although macropinocytosis is largely considered an endocytic process where cells internalize only large amounts of solutes, several pathogens use this pathway to enter into host cells. To investigate whether T. cruzi entry into peritoneal macrophages and LLC-MK2 epithelial cells can be also mediated through a macropinocytosis-like process, we used several experimental strategies presently available to characterize macropinocytosis such as the use of different inhibitors. These macropinocytosis' inhibitors blocked internalization of T. cruzi by host cells. To further support this, immunofluorescence microscopy and scanning electron microscopy techniques were used. Field emission scanning electron microscopy revealed that after treatment, parasites remained attached to the external side of host cell plasma membrane. Proteins such as Rabankyrin 5, tyrosine kinases, Pak1 and actin microfilaments, which participate in macropinosome formation, were localized at T. cruzi entry sites. We also observed co-localization between the parasite and an endocytic fluid phase marker. All together, these results indicate that T. cruzi is able to use multiple mechanisms of penetration into host cell, including macropinocytosis.
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Affiliation(s)
- E S Barrias
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro - Av. Carlos Chagas Filho, 373, Bloco G - subsolo, Cidade Universitária, Ilha do Fundão, Rio de Janeiro 21941-902, Brazil
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A 14-3-3γ dimer-based scaffold bridges CtBP1-S/BARS to PI(4)KIIIβ to regulate post-Golgi carrier formation. Nat Cell Biol 2012; 14:343-54. [PMID: 22366688 DOI: 10.1038/ncb2445] [Citation(s) in RCA: 233] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Accepted: 01/17/2012] [Indexed: 11/08/2022]
Abstract
Large pleiomorphic carriers leave the Golgi complex for the plasma membrane by en bloc extrusion of specialized tubular domains, which then undergo fission. Several components of the underlying molecular machinery have been identified, including those involved in the budding/initiation of tubular carrier precursors (for example, the phosphoinositide kinase PI(4)KIIIβ, the GTPase ARF, and FAPP2), and in the fission of these precursors (for example, PKD, CtBP1-S/BARS). However, how these proteins interact to bring about carrier formation is poorly understood. Here, we describe a protein complex that mediates carrier formation and contains budding and fission molecules, as well as other molecules, such as the adaptor protein 14-3-3γ. Specifically, we show that 14-3-3γ dimers bridge CtBP1-S/BARS with PI(4)KIIIβ, and that the resulting complex is stabilized by phosphorylation by PKD and PAK. Disrupting the association of these proteins inhibits the fission of elongating carrier precursors, indicating that this complex couples the carrier budding and fission processes.
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Abstract
Ribbon synapses continuously transmit graded membrane potential changes into changes of synaptic vesicle exocytosis and rely on intense synaptic membrane trafficking. The synaptic ribbon is considered central to this process. In the present study we asked whether tonically active ribbon synapses are associated with the generation of certain lipids, specifically the highly active signaling phospholipid phosphatidic acid (PA). Using PA-sensor proteins, we demonstrate that PA is enriched at mouse retinal ribbon synapses in close vicinity to the synaptic ribbon in situ. As shown by heterologous expression, RIBEYE, a main component of synaptic ribbons, is responsible for PA binding at synaptic ribbons. Furthermore, RIBEYE is directly involved in the synthesis of PA. Using various independent substrate binding and enzyme assays, we demonstrate that the B domain of RIBEYE possesses lysophosphatidic acid (LPA) acyltransferase (LPAAT) activity, which leads to the generation of PA from LPA. Since an LPAAT-deficient RIBEYE mutant does not recruit PA-binding proteins to artificial synaptic ribbons, whereas wild-type RIBEYE supports PA binding, we conclude that the LPAAT activity of the RIBEYE(B) domain is a physiologically relevant source of PA generation at the synaptic ribbon. We propose that PA generated at synaptic ribbons likely facilitates synaptic vesicle trafficking.
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Kantardzhieva A, Peppi M, Lane WS, Sewell WF. Protein composition of immunoprecipitated synaptic ribbons. J Proteome Res 2011; 11:1163-74. [PMID: 22103298 DOI: 10.1021/pr2008972] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The synaptic ribbon is an electron-dense structure found in hair cells and photoreceptors. The ribbon is surrounded by neurotransmitter-filled vesicles and considered to play a role in vesicle release. We generated an objective, quantitative analysis of the protein composition of the ribbon complex using a mass spectrometry-based proteomics analysis. Our use of affinity-purified ribbons and control IgG immunoprecipitations ensure that the identified proteins are indeed associated with the ribbon complex. The use of mouse tissue, where the proteome is complete, generated a comprehensive analysis of the candidates. We identified 30 proteins (comprising 56 isoforms and subunits) associated with the ribbon complex. The ribbon complex primarily comprises proteins found in conventional synapses, which we categorized into 6 functional groups: vesicle handling (38.5%), scaffold (7.3%), cytoskeletal molecules (20.6%), phosphorylation enzymes (10.6%), molecular chaperones (8.2%), and transmembrane proteins from the presynaptic membrane firmly attached to the ribbon (11.3%). The 3 CtBP isoforms represent the major protein in the ribbon whether calculated by molar amount (30%) or by mass (20%). The relatively high quantity of phosphorylation enzymes suggests a very active and regulated structure. The ribbon appears to comprise a concentrated cluster of proteins dealing with vesicle creation, retention and distribution, and consequent exocytosis.
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Affiliation(s)
- A Kantardzhieva
- Eaton-Peabody Laboratory, Department of Otology and Laryngology, Massachusetts Eye and Ear Infirmary and Harvard Medical School, 243 Charles Street, Boston, Massachusetts 02114, United States
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Gu Z, Noss EH, Hsu VW, Brenner MB. Integrins traffic rapidly via circular dorsal ruffles and macropinocytosis during stimulated cell migration. ACTA ACUST UNITED AC 2011; 193:61-70. [PMID: 21464228 PMCID: PMC3082178 DOI: 10.1083/jcb.201007003] [Citation(s) in RCA: 133] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
In response to growth factor stimulation, integrins transit through recycling endosomes to reach newly forming focal adhesions at the cell’s leading edge. During cell migration, integrins are redistributed from focal adhesions undergoing disassembly at the cell’s trailing edges to new focal adhesions assembling at leading edges. The initial step of integrin redistribution is thought to require clathrin-mediated endocytosis. However, whether clathrin-mediated endocytosis functions in different contexts, such as basal versus stimulated migration, has not been determined. In this paper, we examine the spatial and temporal redistribution of integrins from focal adhesions upon stimulation by growth factors. Four-dimensional confocal live-cell imaging along with functional analysis reveals that surface integrins do not undergo significant endocytosis at ventral focal adhesions upon cell stimulation with the platelet-derived growth factor. Rather, they abruptly redistribute to dorsal circular ruffles, where they are internalized through macropinocytosis. The internalized integrins then transit through recycling endosomal compartments to repopulate newly formed focal adhesions on the ventral surface. These findings explain why integrins have long been observed to redistribute through both surface-based and internal routes and identify a new function for macropinocytosis during growth factor–induced cell migration.
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Affiliation(s)
- Zhizhan Gu
- Division of Rheumatology, Immunology, and Allergy, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
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Sandvig K, Pust S, Skotland T, van Deurs B. Clathrin-independent endocytosis: mechanisms and function. Curr Opin Cell Biol 2011; 23:413-20. [PMID: 21466956 DOI: 10.1016/j.ceb.2011.03.007] [Citation(s) in RCA: 178] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2011] [Revised: 03/07/2011] [Accepted: 03/11/2011] [Indexed: 12/17/2022]
Abstract
It is now about 20 years since we first wrote reviews about clathrin-independent endocytosis. The challenge at the time was to convince the reader about its existence. Then the suggestion came up that caveolae might be responsible for the uptake. However, clearly this could not be the case since a large fraction of the clathrin-independent uptake is dynamin-independent. Today, two decades later, the field has developed considerably. New techniques have enabled a detailed analysis of several clathrin-independent endocytic mechanisms, and caveolae have been found to be mostly stable structures having several functions of their own. This article aims at providing a brief update on the importance of clathrin-independent endocytic mechanisms, how the processes are regulated differentially, for instance on the poles of polarized cells, and the challenges in studying them.
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Affiliation(s)
- Kirsten Sandvig
- Department of Biochemistry, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway.
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Abstract
Macropinocytosis is a regulated form of endocytosis that mediates the non-selective uptake of solute molecules, nutrients and antigens. It is an actin-dependent process initiated from surface membrane ruffles that give rise to large endocytic vacuoles called macropinosomes. Macropinocytosis is important in a range of physiological processes; it is highly active in macrophages and dendritic cells where it is a major pathway for the capture of antigens, it is relevant to cell migration and tumour metastasis and it represents a portal of cell entry exploited by a range of pathogens. The molecular basis for the formation and maturation of macropinosomes has only recently begun to be defined. Here, we review the general characteristics of macropinocytosis, describe some of the regulators of this pathway, which have been identified to date and highlight strategies to explore the relevance of this endocytosis pathway in vivo.
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Saeed MF, Kolokoltsov AA, Albrecht T, Davey RA. Cellular entry of ebola virus involves uptake by a macropinocytosis-like mechanism and subsequent trafficking through early and late endosomes. PLoS Pathog 2010; 6:e1001110. [PMID: 20862315 PMCID: PMC2940741 DOI: 10.1371/journal.ppat.1001110] [Citation(s) in RCA: 327] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2009] [Accepted: 08/17/2010] [Indexed: 12/17/2022] Open
Abstract
Zaire ebolavirus (ZEBOV), a highly pathogenic zoonotic virus, poses serious public health, ecological and potential bioterrorism threats. Currently no specific therapy or vaccine is available. Virus entry is an attractive target for therapeutic intervention. However, current knowledge of the ZEBOV entry mechanism is limited. While it is known that ZEBOV enters cells through endocytosis, which of the cellular endocytic mechanisms used remains unclear. Previous studies have produced differing outcomes, indicating potential involvement of multiple routes but many of these studies were performed using noninfectious surrogate systems such as pseudotyped retroviral particles, which may not accurately recapitulate the entry characteristics of the morphologically distinct wild type virus. Here we used replication-competent infectious ZEBOV as well as morphologically similar virus-like particles in specific infection and entry assays to demonstrate that in HEK293T and Vero cells internalization of ZEBOV is independent of clathrin, caveolae, and dynamin. Instead the uptake mechanism has features of macropinocytosis. The binding of virus to cells appears to directly stimulate fluid phase uptake as well as localized actin polymerization. Inhibition of key regulators of macropinocytosis including Pak1 and CtBP/BARS as well as treatment with the drug EIPA, which affects macropinosome formation, resulted in significant reduction in ZEBOV entry and infection. It is also shown that following internalization, the virus enters the endolysosomal pathway and is trafficked through early and late endosomes, but the exact site of membrane fusion and nucleocapsid penetration in the cytoplasm remains unclear. This study identifies the route for ZEBOV entry and identifies the key cellular factors required for the uptake of this filamentous virus. The findings greatly expand our understanding of the ZEBOV entry mechanism that can be applied to development of new therapeutics as well as provide potential insight into the trafficking and entry mechanism of other filoviruses. Filoviruses, including Zaire ebolavirus (ZEBOV), are among the most pathogenic viruses known. Our understanding of how these viruses enter into host cells is very limited. A deeper understanding of this process would enable the design of better targeted antiviral therapies. This study defines in detail, key steps of ZEBOV cellular uptake and trafficking into cells using wild type virus as well as the host factors that are responsible for permitting virus entry into cells. Our data indicated that the primary mechanism of ZEBOV uptake is a macropinocytosis-like process that delivers the virus to early endosomes and subsequently to late endosomes. These findings aid in our understanding of how filoviruses infect cells and suggest that disruption of macropinocytosis may be useful in treatment of infection.
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Affiliation(s)
- Mohammad F. Saeed
- Department of Microbiology & Immunology, The University of Texas Medical Branch, Galveston, Texas, United States of America
- Galveston National Laboratory, The University of Texas Medical Branch, Galveston, Texas, United States of America
- Institute of Human Infection and Immunity, The University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Andrey A. Kolokoltsov
- Department of Microbiology & Immunology, The University of Texas Medical Branch, Galveston, Texas, United States of America
- Galveston National Laboratory, The University of Texas Medical Branch, Galveston, Texas, United States of America
- Institute of Human Infection and Immunity, The University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Thomas Albrecht
- Department SK, Building 37, NASA, Houston, Texas, United States of America
| | - Robert A. Davey
- Department of Microbiology & Immunology, The University of Texas Medical Branch, Galveston, Texas, United States of America
- Galveston National Laboratory, The University of Texas Medical Branch, Galveston, Texas, United States of America
- Institute of Human Infection and Immunity, The University of Texas Medical Branch, Galveston, Texas, United States of America
- * E-mail:
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Macropinocytotic uptake and infection of human epithelial cells with species B2 adenovirus type 35. J Virol 2010; 84:5336-50. [PMID: 20237079 DOI: 10.1128/jvi.02494-09] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human adenovirus serotype 35 (HAdV-35; here referred to as Ad35) causes kidney and urinary tract infections and infects respiratory organs of immunocompromised individuals. Unlike other adenoviruses, Ad35 has a low seroprevalence, which makes Ad35-based vectors promising candidates for gene therapy. Ad35 utilizes CD46 and integrins as receptors for infection of epithelial and hematopoietic cells. Here we show that infectious entry of Ad35 into HeLa cells, human kidney HK-2 cells, and normal human lung fibroblasts strongly depended on CD46 and integrins but not heparan sulfate and variably required the large GTPase dynamin. Ad35 infections were independent of expression of the carboxy-terminal domain of AP180, which effectively blocks clathrin-mediated uptake. Ad35 infections were inhibited by small chemicals against serine/threonine kinase Pak1 (p21-activated kinase), protein kinase C (PKC), sodium-proton exchangers, actin, and acidic organelles. Remarkably, the F-actin inhibitor jasplakinolide, the Pak1 inhibitor IPA-3, or the sodium-proton exchange inhibitor 5-(N-ethyl-N-isopropyl) amiloride (EIPA) blocked endocytic uptake of Ad35. Dominant-negative proteins or small interfering RNAs against factors driving macropinocytosis, including the small GTPase Rac1, Pak1, or the Pak1 effector C-terminal binding protein 1 (CtBP1), potently inhibited Ad35 infection. Confocal laser scanning microscopy, electron microscopy, and live cell imaging showed that Ad35 colocalized with fluid-phase markers in large endocytic structures that were positive for CD46, alphanu integrins, and also CtBP1. Our results extend earlier observations with HAdV-3 (Ad3) and establish macropinocytosis as an infectious pathway for species B human adenoviruses in epithelial and hematopoietic cells.
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Liu J, Sun Y, Oster GF, Drubin DG. Mechanochemical crosstalk during endocytic vesicle formation. Curr Opin Cell Biol 2010; 22:36-43. [PMID: 20022735 PMCID: PMC2822040 DOI: 10.1016/j.ceb.2009.11.009] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2009] [Accepted: 11/20/2009] [Indexed: 12/13/2022]
Abstract
Membrane curvature has emerged as a key regulatory factor in endocytic vesicle formation. From a theoretical perspective, we summarize recent progress in understanding how membrane curvature and biochemical pathways are coupled and orchestrated during the coherent process of endocytic vesicle formation. We mainly focus on clathrin-mediated and actin-mediated endocytosis in yeast and in mammalian cells. We further speculate on how mechanochemical feedback could modulate other membrane-remodeling processes.
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Affiliation(s)
| | - Yidi Sun
- Department of Molecular and Cell Biology, UC-Berkeley
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Beck R, Ravet M, Wieland F, Cassel D. The COPI system: Molecular mechanisms and function. FEBS Lett 2009; 583:2701-9. [DOI: 10.1016/j.febslet.2009.07.032] [Citation(s) in RCA: 214] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2009] [Revised: 07/07/2009] [Accepted: 07/13/2009] [Indexed: 02/03/2023]
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