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Moqadam M, Gartan P, Talandashti R, Chiapparino A, Titeca K, Gavin AC, Reuter N. A Membrane-Assisted Mechanism for the Release of Ceramide from the CERT START Domain. J Phys Chem B 2024; 128:6338-6351. [PMID: 38903016 PMCID: PMC11228987 DOI: 10.1021/acs.jpcb.4c02398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2024] [Revised: 05/26/2024] [Accepted: 06/11/2024] [Indexed: 06/22/2024]
Abstract
Ceramide transfer protein CERT is the mediator of nonvesicular transfer of ceramide from the ER to Golgi. In CERT, START is the domain responsible for the binding and transport of ceramide. A wealth of structural data has revealed a helix-grip fold surrounding a large hydrophobic cavity holding the ceramide. Yet, little is known about the mechanisms by which START releases the ceramide through the polar region and into the packed environment of cellular membranes. As such events do not lend themselves easily to experimental investigations, we used multiple unbiased microsecond-long molecular simulations. We propose a membrane-assisted mechanism in which the membrane acts as an allosteric effector initiating the release of ceramide and where the passage of the ceramide acyl chains is facilitated by the intercalation of a single phosphatidylcholine lipid in the cavity, practically greasing the ceramide way out. We verify using free energy calculation and experimental lipidomics data that CERT forms stable complexes with phosphatidylcholine lipids, in addition to ceramide, thus providing validation for the proposed mechanism.
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Affiliation(s)
- Mahmoud Moqadam
- Department
of Chemistry, University of Bergen, Bergen 5020, Norway
- Computational
Biology Unit, Department of Informatics, University of Bergen, Bergen 5020, Norway
| | - Parveen Gartan
- Department
of Chemistry, University of Bergen, Bergen 5020, Norway
- Computational
Biology Unit, Department of Informatics, University of Bergen, Bergen 5020, Norway
| | - Reza Talandashti
- Department
of Chemistry, University of Bergen, Bergen 5020, Norway
- Computational
Biology Unit, Department of Informatics, University of Bergen, Bergen 5020, Norway
| | - Antonella Chiapparino
- European
Molecular Biology Laboratory, EMBL, Meyerhofstrasse 1, Heidelberg D-69117, Germany
| | - Kevin Titeca
- European
Molecular Biology Laboratory, EMBL, Meyerhofstrasse 1, Heidelberg D-69117, Germany
- Department
of Cell Physiology and Metabolism, University
of Geneva, CMU Rue Michel-Servet 1, Genève 4 1211, Switzerland
| | - Anne-Claude Gavin
- Department
of Cell Physiology and Metabolism, University
of Geneva, CMU Rue Michel-Servet 1, Genève 4 1211, Switzerland
| | - Nathalie Reuter
- Department
of Chemistry, University of Bergen, Bergen 5020, Norway
- Computational
Biology Unit, Department of Informatics, University of Bergen, Bergen 5020, Norway
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2
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Stadler KA, Ortiz-Joya LJ, Singh Sahrawat A, Buhlheller C, Gruber K, Pavkov-Keller T, O'Hagan TB, Guarné A, Pulido S, Marín-Villa M, Zangger K, Gubensäk N. Structural investigation of Trypanosoma cruzi Akt-like kinase as drug target against Chagas disease. Sci Rep 2024; 14:10039. [PMID: 38693166 PMCID: PMC11063076 DOI: 10.1038/s41598-024-59654-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Accepted: 04/12/2024] [Indexed: 05/03/2024] Open
Abstract
According to the World Health Organization, Chagas disease (CD) is the most prevalent poverty-promoting neglected tropical disease. Alarmingly, climate change is accelerating the geographical spreading of CD causative parasite, Trypanosoma cruzi, which additionally increases infection rates. Still, CD treatment remains challenging due to a lack of safe and efficient drugs. In this work, we analyze the viability of T. cruzi Akt-like kinase (TcAkt) as drug target against CD including primary structural and functional information about a parasitic Akt protein. Nuclear Magnetic Resonance derived information in combination with Molecular Dynamics simulations offer detailed insights into structural properties of the pleckstrin homology (PH) domain of TcAkt and its binding to phosphatidylinositol phosphate ligands (PIP). Experimental data combined with Alpha Fold proposes a model for the mechanism of action of TcAkt involving a PIP-induced disruption of the intramolecular interface between the kinase and the PH domain resulting in an open conformation enabling TcAkt kinase activity. Further docking experiments reveal that TcAkt is recognized by human inhibitors PIT-1 and capivasertib, and TcAkt inhibition by UBMC-4 and UBMC-6 is achieved via binding to TcAkt kinase domain. Our in-depth structural analysis of TcAkt reveals potential sites for drug development against CD, located at activity essential regions.
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Affiliation(s)
- Karina A Stadler
- Institute of Chemistry/Organic and Bioorganic Chemistry, University of Graz, Graz, Austria
| | - Lesly J Ortiz-Joya
- Institute of Chemistry/Organic and Bioorganic Chemistry, University of Graz, Graz, Austria
- Programa de Estudio y Control de Enfermedades Tropicales (PECET), Facultad de Medicina, Universidad de Antioquia, Medellín, Colombia
- Department of Biochemistry, McGill University, Montreal, Canada
| | - Amit Singh Sahrawat
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
- Innophore GmbH, Graz, Austria
| | | | - Karl Gruber
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
- Innophore GmbH, Graz, Austria
- Field of Excellence BioHealth, University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
| | - Tea Pavkov-Keller
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
- Field of Excellence BioHealth, University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
| | | | - Alba Guarné
- Department of Biochemistry, McGill University, Montreal, Canada
| | - Sergio Pulido
- Programa de Estudio y Control de Enfermedades Tropicales (PECET), Facultad de Medicina, Universidad de Antioquia, Medellín, Colombia
- LifeFactors ZF SAS, Rionegro, Colombia
| | - Marcel Marín-Villa
- Programa de Estudio y Control de Enfermedades Tropicales (PECET), Facultad de Medicina, Universidad de Antioquia, Medellín, Colombia
| | - Klaus Zangger
- Institute of Chemistry/Organic and Bioorganic Chemistry, University of Graz, Graz, Austria.
- Field of Excellence BioHealth, University of Graz, Graz, Austria.
- BioTechMed-Graz, Graz, Austria.
| | - Nina Gubensäk
- Institute of Molecular Biosciences, University of Graz, Graz, Austria.
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3
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Larsen AH. Understanding cytokinesis interaction by interaction. Structure 2024; 32:120-121. [PMID: 38306987 DOI: 10.1016/j.str.2024.01.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 01/04/2024] [Accepted: 01/04/2024] [Indexed: 02/04/2024]
Abstract
In this issue of Structure, Hall et al.1 investigate the binding modes of anillin-like Mid1. During cytokinesis, Mid1 connects the contractile ring to the plasma membrane. Using computer simulations, the authors demonstrated how this connection is established via the L3 loop of the C2 domain.
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4
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Hall AR, Choi YK, Im W, Vavylonis D. Anillin-related Mid1 as an adaptive and multimodal contractile ring anchoring protein: A simulation study. Structure 2024; 32:242-252.e2. [PMID: 38103546 PMCID: PMC10872332 DOI: 10.1016/j.str.2023.11.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 10/13/2023] [Accepted: 11/21/2023] [Indexed: 12/19/2023]
Abstract
Cytokinesis of animal and fungi cells depends crucially on the anillin scaffold proteins. Fission yeast anillin-related Mid1 anchors cytokinetic ring precursor nodes to the membrane. However, it is unclear if both of its Pleckstrin Homology (PH) and C2 C-terminal domains bind to the membrane as monomers or dimers, and if one domain plays a dominant role. We studied Mid1 membrane binding with all-atom molecular dynamics near a membrane with yeast-like lipid composition. In simulations with the full C terminal region started away from the membrane, Mid1 binds through the disordered L3 loop of C2 in a vertical orientation, with the PH away from the membrane. However, a configuration with both C2 and PH initially bound to the membrane remains associated with the membrane. Simulations of C2-PH dimers show extensive asymmetric membrane contacts. These multiple modes of binding may reflect Mid1's multiple interactions with membranes, node proteins, and ability to sustain mechanical forces.
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Affiliation(s)
- Aaron R Hall
- Department of Physics, Lehigh University, Bethlehem, PA 18017, USA
| | - Yeol Kyo Choi
- Department of Biological Sciences, Lehigh University, Bethlehem, PA 18017, USA
| | - Wonpil Im
- Department of Biological Sciences, Lehigh University, Bethlehem, PA 18017, USA
| | - Dimitrios Vavylonis
- Department of Physics, Lehigh University, Bethlehem, PA 18017, USA; Center for Computational Biology, Flatiron Institute, New York, NY 10010, USA.
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5
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Oh BC. Phosphoinositides and intracellular calcium signaling: novel insights into phosphoinositides and calcium coupling as negative regulators of cellular signaling. Exp Mol Med 2023; 55:1702-1712. [PMID: 37524877 PMCID: PMC10474053 DOI: 10.1038/s12276-023-01067-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 06/05/2023] [Accepted: 06/07/2023] [Indexed: 08/02/2023] Open
Abstract
Intracellular calcium (Ca2+) and phosphoinositides (PIPs) are crucial for regulating cellular activities such as metabolism and cell survival. Cells maintain precise intracellular Ca2+ and PIP levels via the actions of a complex system of Ca2+ channels, transporters, Ca2+ ATPases, and signaling effectors, including specific lipid kinases, phosphatases, and phospholipases. Recent research has shed light on the complex interplay between Ca2+ and PIP signaling, suggesting that elevated intracellular Ca2+ levels negatively regulate PIP signaling by inhibiting the membrane localization of PIP-binding proteins carrying specific domains, such as the pleckstrin homology (PH) and Ca2+-independent C2 domains. This dysregulation is often associated with cancer and metabolic diseases. PIPs recruit various proteins with PH domains to the plasma membrane in response to growth hormones, which activate signaling pathways regulating metabolism, cell survival, and growth. However, abnormal PIP signaling in cancer cells triggers consistent membrane localization and activation of PIP-binding proteins. In the context of obesity, an excessive intracellular Ca2+ level prevents the membrane localization of the PIP-binding proteins AKT, IRS1, and PLCδ via Ca2+-PIPs, contributing to insulin resistance and other metabolic diseases. Furthermore, an excessive intracellular Ca2+ level can cause functional defects in subcellular organelles such as the endoplasmic reticulum (ER), lysosomes, and mitochondria, causing metabolic diseases. This review explores how intracellular Ca2+ overload negatively regulates the membrane localization of PIP-binding proteins.
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Affiliation(s)
- Byung-Chul Oh
- Department of Physiology, Lee Gil Ya Cancer and Diabetes Institute, Gachon College of Medicine, Incheon, 21999, Republic of Korea.
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6
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Smith ER, Caulley LR, Storm AR, Hulse-Kemp AM, Stoeckman AK. Gossypium hirsutum gene of unknown function Gohir.A03G007700.1 encodes a potential VAN3-binding protein with a phosphoinositide-binding site. MICROPUBLICATION BIOLOGY 2023; 2023:10.17912/micropub.biology.000669. [PMID: 36798590 PMCID: PMC9926292 DOI: 10.17912/micropub.biology.000669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Revised: 01/04/2023] [Accepted: 01/29/2023] [Indexed: 02/18/2023]
Abstract
A gene of unknown function, Gohir.A03G007700.1 (gene ID: Gohir.A03G007700_UTX-TM1_v2.1; transcript ID: Gohir.A03G007700.1_UTX-TM1_v2.1), identified in Gossypium hirsutum was studied using bioinformatic analyses of the sequence and structure of its encoded protein. Results from domain prediction, conserved residues and structure comparison indicate the encoded plant-specific protein (UniProt A0A1U8N485) is part of the VAN3-binding protein family with a conserved phosphoinositide-binding site. Homology comparison suggests functional similarity with Arabidopsis FORKED-like FL5 and 6, which localize to the Golgi apparatus and are linked to vein development and leaf size phenotypes.
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Affiliation(s)
- Emma R. Smith
- Chemistry Department, Bethel University, Saint Paul, MN USA
| | | | - Amanda R Storm
- Department of Biology, Western Carolina University, Cullowhee, NC USA
,
Correspondence to: Amanda R Storm (
)
| | - Amanda M. Hulse-Kemp
- Genomics and Bioinformatics Research Unit, The Agricultural Research Service of U.S. Department of Agriculture, Raleigh, NC USA
,
Department of Crop and Soil Sciences, North Carolina State University, Raleigh, NC
,
Correspondence to: Amanda M. Hulse-Kemp (
)
| | - Angela K. Stoeckman
- Chemistry Department, Bethel University, Saint Paul, MN USA
,
Correspondence to: Angela K. Stoeckman (
)
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7
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Hall AR, Choi YK, Im W, Vavylonis D. Anillin Related Mid1 as an Adaptive and Multimodal Contractile Ring Anchoring Protein: A Simulation Study. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.27.525865. [PMID: 36747616 PMCID: PMC9900988 DOI: 10.1101/2023.01.27.525865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The organization of the cytokinetic ring at the cell equator of dividing animal and fungi cells depends crucially on the anillin scaffold proteins. In fission yeast, anillin related Mid1 binds to the plasma membrane and helps anchor and organize a medial broad band of cytokinetic nodes, which are the precursors of the contractile ring. Similar to other anillins, Mid1 contains a C terminal globular domain with two potential regions for membrane binding, the Pleckstrin Homology (PH) and C2 domains, and an N terminal intrinsically disordered region that is strongly regulated by phosphorylation. Previous studies have shown that both PH and C2 domains can associate with the membrane, preferring phosphatidylinositol-(4,5)-bisphosphate (PIP 2 ) lipids. However, it is unclear if they can simultaneously bind to the membrane in a way that allows dimerization or oligomerization of Mid1, and if one domain plays a dominant role. To elucidate Mid1's membrane binding mechanism, we used the available structural information of the C terminal region of Mid1 in all-atom molecular dynamics (MD) near a membrane with a lipid composition based on experimental measurements (including PIP 2 lipids). The disordered L3 loop of C2, as well as the PH domain, separately bind the membrane through charged lipid contacts. In simulations with the full C terminal region started away from the membrane, Mid1 binds through the L3 loop and is stabilized in a vertical orientation with the PH domain away from the membrane. However, a configuration with both C2 and PH initially bound to the membrane remains associated with the membrane. These multiple modes of binding may reflect Mid1's multiple interactions with membranes and other node proteins, and ability to sustain mechanical forces.
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8
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Structural Insights Uncover the Specific Phosphoinositide Recognition by the PH1 Domain of Arap3. Int J Mol Sci 2023; 24:ijms24021125. [PMID: 36674645 PMCID: PMC9865853 DOI: 10.3390/ijms24021125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 12/28/2022] [Accepted: 01/04/2023] [Indexed: 01/11/2023] Open
Abstract
Arap3, a dual GTPase-activating protein (GAP) for the small GTPases Arf6 and RhoA, plays key roles in regulating a wide range of biological processes, including cancer cell invasion and metastasis. It is known that Arap3 is a PI3K effector that can bind directly to PI(3,4,5)P3, and the PI(3,4,5)P3-mediated plasma membrane recruitment is crucial for its function. However, the molecular mechanism of how the protein recognizes PI(3,4,5)P3 remains unclear. Here, using liposome pull-down and surface plasmon resonance (SPR) analysis, we found that the N-terminal first pleckstrin homology (PH) domain (Arap3-PH1) can interact with PI(3,4,5)P3 and, with lower affinity, with PI(4,5)P2. To understand how Arap3-PH1 and phosphoinositide (PIP) lipids interact, we solved the crystal structure of the Arap3-PH1 in the apo form and complex with diC4-PI(3,4,5)P3. We also characterized the interactions of Arap3-PH1 with diC4-PI(3,4,5)P3 and diC4-PI(4,5)P2 in solution by nuclear magnetic resonance (NMR) spectroscopy. Furthermore, we found overexpression of Arap3 could inhibit breast cancer cell invasion in vitro, and the PIPs-binding ability of the PH1 domain is essential for this function.
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9
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Prakaash D, Fagnen C, Cook GP, Acuto O, Kalli AC. Molecular dynamics simulations reveal membrane lipid interactions of the full-length lymphocyte specific kinase (Lck). Sci Rep 2022; 12:21121. [PMID: 36476673 PMCID: PMC9729596 DOI: 10.1038/s41598-022-25603-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 12/01/2022] [Indexed: 12/12/2022] Open
Abstract
The membrane-bound lymphocyte-specific protein-tyrosine kinase (Lck) triggers T cell antigen receptor signalling to initiate adaptive immune responses. Despite many structure-function studies, the mode of action of Lck and the potential role of plasma membrane lipids in regulating Lck's activity remains elusive. Advances in molecular dynamics simulations of membrane proteins in complex lipid bilayers have opened a new perspective in gathering such information. Here, we have modelled the full-length Lck open and closed conformations using data available from different crystalographic studies and simulated its interaction with the inner leaflet of the T cell plasma membrane. In both conformations, we found that the unstructured unique domain and the structured domains including the kinase interacted with the membrane with a preference for PIP lipids. Interestingly, our simulations suggest that the Lck-SH2 domain interacts with lipids differently in the open and closed Lck conformations, demonstrating that lipid interaction can potentially regulate Lck's conformation and in turn modulate T cell signalling. Additionally, the Lck-SH2 and kinase domain residues that significantly contacted PIP lipids are found to be conserved among the Src family of kinases, thereby potentially representing similar PIP interactions within the family.
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Affiliation(s)
- Dheeraj Prakaash
- Leeds Institute of Cardiovascular and Metabolic Medicine, School of Medicine, University of Leeds, Leeds, UK
- Astbury Center for Structural Molecular Biology, University of Leeds, Leeds, UK
| | - Charline Fagnen
- Leeds Institute of Cardiovascular and Metabolic Medicine, School of Medicine, University of Leeds, Leeds, UK
- Astbury Center for Structural Molecular Biology, University of Leeds, Leeds, UK
| | - Graham P Cook
- School of Medicine, Leeds Institute of Medical Research, University of Leeds, Leeds, UK
| | - Oreste Acuto
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Antreas C Kalli
- Leeds Institute of Cardiovascular and Metabolic Medicine, School of Medicine, University of Leeds, Leeds, UK.
- Astbury Center for Structural Molecular Biology, University of Leeds, Leeds, UK.
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10
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Lee J. Does IFITM3 link inflammation to tumorigenesis? BMB Rep 2022; 55:602-608. [PMID: 36404597 PMCID: PMC9813432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 11/17/2022] [Accepted: 11/21/2022] [Indexed: 12/29/2022] Open
Abstract
Uncontrolled chronic inflammation, in most cases due to excessive cytokine signaling through their receptors, is known to contribute to the development of tumorigenesis. Recently, it has been reported that the antiviral membrane protein interferon-induced transmembrane protein 3 (IFITM3), induced by interferon signaling as part of the inflammatory response after viral infection, contributes to the development of B-cell malignancy. The unexpected oncogenic signaling of IFITM3 upon malignant B cell activation elucidated the mechanism by which the uncontrolled expression of inflammatory proteins contributes to leukemogenesis. In this review, the potential effects of inflammatory cytokines on upregulation of IFITM3 and its contribution to tumorigenesis are discussed. [BMB Reports 2022; 55(12): 602-608].
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Affiliation(s)
- Jaewoong Lee
- School of Biosystems and Biomedical Sciences, College of Health Science, Korea University, Seoul 02841, Korea
- Interdisciplinary Program in Precision Public Health, Korea University, Seoul 02841, Korea
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11
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Lee J. Does IFITM3 link inflammation to tumorigenesis? BMB Rep 2022; 55:602-608. [PMID: 36404597 PMCID: PMC9813432 DOI: 10.5483/bmbrep.2022.55.12.161] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 11/17/2022] [Accepted: 11/21/2022] [Indexed: 11/15/2023] Open
Abstract
Uncontrolled chronic inflammation, in most cases due to excessive cytokine signaling through their receptors, is known to contribute to the development of tumorigenesis. Recently, it has been reported that the antiviral membrane protein interferon-induced transmembrane protein 3 (IFITM3), induced by interferon signaling as part of the inflammatory response after viral infection, contributes to the development of B-cell malignancy. The unexpected oncogenic signaling of IFITM3 upon malignant B cell activation elucidated the mechanism by which the uncontrolled expression of inflammatory proteins contributes to leukemogenesis. In this review, the potential effects of inflammatory cytokines on upregulation of IFITM3 and its contribution to tumorigenesis are discussed. [BMB Reports 2022; 55(12): 602-608].
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Affiliation(s)
- Jaewoong Lee
- School of Biosystems and Biomedical Sciences, College of Health Science, Korea University, Seoul 02841, Korea
- Interdisciplinary Program in Precision Public Health, Korea University, Seoul 02841, Korea
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12
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Le Huray KIP, Bunney TD, Pinotsis N, Kalli AC, Katan M. Characterization of the membrane interactions of phospholipase Cγ reveals key features of the active enzyme. SCIENCE ADVANCES 2022; 8:eabp9688. [PMID: 35749497 PMCID: PMC9232102 DOI: 10.1126/sciadv.abp9688] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 05/06/2022] [Indexed: 06/15/2023]
Abstract
PLCγ enzymes are autoinhibited in resting cells and form key components of intracellular signaling that are also linked to disease development. Insights into physiological and aberrant activation of PLCγ require understanding of an active, membrane-bound form, which can hydrolyze inositol-lipid substrates. Here, we demonstrate that PLCγ1 cannot bind membranes unless the autoinhibition is disrupted. Through extensive molecular dynamics simulations and experimental evidence, we characterize membrane binding by the catalytic core domains and reveal previously unknown sites of lipid interaction. The identified sites act in synergy, overlap with autoinhibitory interfaces, and are shown to be critical for the phospholipase activity in cells. This work provides direct evidence that PLCγ1 is inhibited through obstruction of its membrane-binding surfaces by the regulatory region and that activation must shift PLCγ1 to a conformation competent for membrane binding. Knowledge of the critical sites of membrane interaction extends the mechanistic framework for activation, dysregulation, and therapeutic intervention.
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Affiliation(s)
- Kyle I. P. Le Huray
- Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT UK
- Leeds Institute of Cardiovascular and Metabolic Medicine, School of Medicine, University of Leeds, Leeds LS2 9JT, UK
| | - Tom D. Bunney
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, Gower St., London WC1E 6BT, UK
| | - Nikos Pinotsis
- Institute of Structural and Molecular Biology, Birkbeck College, London, WC1E 6BT, UK
| | - Antreas C. Kalli
- Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
- Leeds Institute of Cardiovascular and Metabolic Medicine, School of Medicine, University of Leeds, Leeds LS2 9JT, UK
| | - Matilda Katan
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, Gower St., London WC1E 6BT, UK
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