1
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Barrantes FJ. The constellation of cholesterol-dependent processes associated with SARS-CoV-2 infection. Prog Lipid Res 2022; 87:101166. [PMID: 35513161 PMCID: PMC9059347 DOI: 10.1016/j.plipres.2022.101166] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 04/26/2022] [Accepted: 04/27/2022] [Indexed: 01/11/2023]
Abstract
The role of cholesterol in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and other coronavirus-host cell interactions is currently being discussed in the context of two main scenarios: i) the presence of the neutral lipid in cholesterol-rich lipid domains involved in different steps of the viral infection and ii) the alteration of metabolic pathways by the virus over the course of infection. Cholesterol-enriched lipid domains have been reported to occur in the lipid envelope membrane of the virus, in the host-cell plasma membrane, as well as in endosomal and other intracellular membrane cellular compartments. These membrane subdomains, whose chemical and physical properties distinguish them from the bulk lipid bilayer, have been purported to participate in diverse phenomena, from virus-host cell fusion to intracellular trafficking and exit of the virions from the infected cell. SARS-CoV-2 recruits many key proteins that participate under physiological conditions in cholesterol and lipid metabolism in general. This review analyses the status of cholesterol and lipidome proteins in SARS-CoV-2 infection and the new horizons they open for therapeutic intervention.
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Affiliation(s)
- Francisco J. Barrantes
- Corresponding author at: BIOMED UCA-CONICET, Av. Alicia Moreau de Justo 1600, C1107AFF Buenos Aires, Argentina
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2
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Interaction of human phospholipid scramblase 1 with cholesterol via CRAC motif is essential for functional regulation and subcellular localization. Int J Biol Macromol 2022; 209:850-857. [PMID: 35439477 DOI: 10.1016/j.ijbiomac.2022.04.087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 04/06/2022] [Accepted: 04/11/2022] [Indexed: 11/21/2022]
Abstract
Human phospholipid scramblase 1 (hPLSCR1) possesses a putative cholesterol binding CRAC (cholesterol interaction/recognition amino acid consensus) motif at the C-terminal. The CRAC motif of hPLSCR1 interacts with cholesterol with an energy of interaction -64.39 KJ mol-1. Since palmitoylated hPLSCR1 localizes to the cholesterol-rich lipid rafts, the interaction between hPLSCR1 and raft cholesterol is highly likely. The present study investigated the hPLSCR1-cholesterol interaction in plasma membrane via putative CRAC motif. hPLSCR1 remains at cholesterol-rich lipid rafts as long as they interact. This interaction is inhibited by mutations in the CRAC motif or cholesterol depletion. Thus, CRAC mutants I300D hPLSCR1 and ΔCRAC hPLSCR1 diffused to the cytoplasm and nucleus. Cholesterol depletion by methyl-β-cyclodextrin (MβCD) dose-dependently reduced cell viability in A549 cells. However, cholesterol depletion released 1.74 ± 0.12 times Ca2+ to the cytosol in A549 cells. Similarly, cholesterol depletion increased intracellular Ca2+ release by 1.81 ± 0.13 and 4.11 ± 0.19 times in RAJI cells expressing hPLSCR1 and ΔCRAC hPLSCR1, respectively. Moreover, the expression of hPLSCR1 and ΔCRAC hPLSCR1 increased apoptosis in RAJI cells by 21 ± 1.5% and 53.50 ± 4.40%, respectively. It was further increased to 43 ± 2.5% and 71.4 ± 1.4% upon cholesterol depletion. The current work links hPLSCR1 expression with cholesterol depletion, intracellular Ca2+ release, and induction of apoptosis.
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3
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Tang JC, Lee CH, Lu T, Vankayala R, Hanley T, Azubuogu C, Li J, Nair MG, Jia W, Anvari B. Membrane Cholesterol Enrichment of Red Blood Cell-Derived Microparticles Results in Prolonged Circulation. ACS APPLIED BIO MATERIALS 2022; 5:650-660. [PMID: 35006664 PMCID: PMC9924066 DOI: 10.1021/acsabm.1c01104] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Particles fabricated from red blood cells (RBCs) can serve as vehicles for delivery of various biomedical cargos. Flipping of phosphatidylserine (PS) from the inner to the outer membrane leaflet normally occurs during the fabrication of such particles. PS externalization is a signal for phagocytic removal of the particles from circulation. Herein, we demonstrate that membrane cholesterol enrichment can mitigate the outward display of PS on microparticles engineered from RBCs. Our in-vitro results show that the phagocytic uptake of cholesterol-enriched particles by murine macrophages takes place at a lowered rate, resulting in reduced uptake as compared to RBC-derived particles without cholesterol enrichment. When administered via tail-vein injection into healthy mice, the percent of injected dose (ID) per gram of extracted blood for cholesterol-enriched particles was ∼1.5 and 1.8 times higher than the particles without cholesterol enrichment at 4 and 24 h, respectively. At 24 h, ∼43% ID/g of the particles without cholesterol enrichment was eliminated or metabolized while ∼94% ID/g of the cholesterol-enriched particles were still retained in the body. These results indicate that membrane cholesterol enrichment is an effective method to reduce PS externalization on the surface of RBC-derived particles and increase their longevity in circulation.
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Affiliation(s)
- Jack C. Tang
- Department of Bioengineering, University of California, Riverside, Riverside, California 92521, United States; Present Address: University of Southern California, Los Angeles, California 90033, United States
| | - Chi-Hua Lee
- Department of Biochemistry, University of California, Riverside, Riverside, California 92521, United States
| | - Thompson Lu
- Department of Bioengineering, University of California, Riverside, Riverside, California 92521, United States
| | - Raviraj Vankayala
- Department of Bioengineering, University of California, Riverside, Riverside, California 92521, United States; Present Address: Indian Institute of Technology Jodhpur, Karwar, Jodhpur, Rajasthan 342037, India
| | - Taylor Hanley
- Department of Bioengineering, University of California, Riverside, Riverside, California 92521, United States
| | - Chiemerie Azubuogu
- Department of Bioengineering, University of California, San Diego, La Jolla, California 92023, United States
| | - Jiang Li
- Division of Biomedical Sciences, University of California, Riverside, Riverside, California 92521, United States
| | - Meera G. Nair
- Division of Biomedical Sciences, University of California, Riverside, Riverside, California 92521, United States
| | - Wangcun Jia
- Beckman Laser Institute & Medical Clinic, University of California, Irvine, Irvine, California 92617, United States
| | - Bahman Anvari
- Department of Bioengineering and Department of Biochemistry, University of California, Riverside, Riverside, California 92521, United States
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4
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Regulation and functions of membrane lipids: Insights from Caenorhabditis elegans. BBA ADVANCES 2022; 2:100043. [PMID: 37082601 PMCID: PMC10074978 DOI: 10.1016/j.bbadva.2022.100043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 12/28/2021] [Accepted: 01/12/2022] [Indexed: 02/08/2023] Open
Abstract
The Caenorhabditis elegans plasma membrane is composed of glycerophospholipids and sphingolipids with a small cholesterol. The C. elegans obtain the majority of the membrane lipids by modifying fatty acids present in the bacterial diet. The metabolic pathways of membrane lipid biosynthesis are well conserved across the animal kingdom. In C. elegans CDP-DAG and Kennedy pathway produce glycerophospholipids. Meanwhile, the sphingolipids are synthesized through a different pathway. They have evolved remarkably diverse mechanisms to maintain membrane lipid homeostasis. For instance, the lipid bilayer stress operates to accomplish homeostasis during any perturbance in the lipid composition. Meanwhile, the PAQR-2/IGLR-2 complex works with FLD-1 to balance unsaturated to saturated fatty acids to maintain membrane fluidity. The loss of membrane lipid homeostasis is observed in many human genetic and metabolic disorders. Since C. elegans conserved such genes and pathways, it can be used as a model organism.
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5
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Cholesterol interaction attenuates scramblase activity of SCRM-1 in the artificial membrane. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2021; 1863:183548. [PMID: 33417966 DOI: 10.1016/j.bbamem.2020.183548] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 12/15/2020] [Accepted: 12/16/2020] [Indexed: 01/09/2023]
Abstract
Phospholipid (PL) scramblases are single-pass transmembrane protein mediating bidirectional PL translocation. Previously in silico analysis of human PL scramblases, predicted the presence of an uncharacterized cholesterol-binding domain spanning partly in the transmembrane helix as well as in the adjacent extracellular coil. This domain was found to be universally conserved in diverse organisms like Caenorhabditis elegans. In this study, we investigated the saturable cholesterol-binding domain of SCRM-1 using fluorescence sterol binding assay, Stern-Volmer quenching, Förster resonance energy transfer, and CD spectroscopy. We observed high-affinity interaction between cholesterol and SCRM-1. Our results support a previous report, which showed that the cholesterol ordering effect reduced the scramblase activity of hPLSCR1. Considering the presence of a high-affinity binding sequence, we propose that the reduction in activity could partly be due to the cholesterol binding. To validate this, we generated a C-terminal helix (CTH) deletion construct (∆CTH SCRM-1) and a point mutation in the putative cholesterol-binding domain I273D SCRM-1. Deletion construct greatly reduced cholesterol affinity along with loss of scramblase activity. In contrast to this, I273D SCRM-1 retained scrambling activity in proteoliposomes containing ~30 mol% cholesterol but lost sterol binding ability. These results suggest that C-terminal helix is crucial for membrane insertion and in the lipid bilayer the scrambling activity of SCRM-1 is modulated through its interaction with cholesterol.
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6
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Buyan A, Cox CD, Barnoud J, Li J, Chan HSM, Martinac B, Marrink SJ, Corry B. Piezo1 Forms Specific, Functionally Important Interactions with Phosphoinositides and Cholesterol. Biophys J 2020; 119:1683-1697. [PMID: 32949489 PMCID: PMC7642233 DOI: 10.1016/j.bpj.2020.07.043] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 07/06/2020] [Accepted: 07/15/2020] [Indexed: 10/25/2022] Open
Abstract
Touch, hearing, and blood pressure regulation require mechanically gated ion channels that convert mechanical stimuli into electrical currents. One such channel is Piezo1, which plays a key role in the transduction of mechanical stimuli in humans and is implicated in diseases, such as xerocytosis and lymphatic dysplasia. There is building evidence that suggests Piezo1 can be regulated by the membrane environment, with the activity of the channel determined by the local concentration of lipids, such as cholesterol and phosphoinositides. To better understand the interaction of Piezo1 with its environment, we conduct simulations of the protein in a complex mammalian bilayer containing more than 60 different lipid types together with electrophysiology and mutagenesis experiments. We find that the protein alters its local membrane composition, enriching specific lipids and forming essential binding sites for phosphoinositides and cholesterol that are functionally relevant and often related to Piezo1-mediated pathologies. We also identify a number of key structural connections between the propeller and pore domains located close to lipid-binding sites.
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Affiliation(s)
- Amanda Buyan
- Research School of Biology, Australian National University, Acton, Canberra, Australia
| | - Charles D Cox
- Victor Chang Cardiac Research Institute, New South Wales, Australia; St Vincent's Clinical School, University of New South Wales, Darlinghurst, New South Wales, Australia.
| | - Jonathan Barnoud
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania; Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, the Netherlands
| | - Jinyuan Li
- Victor Chang Cardiac Research Institute, New South Wales, Australia
| | - Hannah S M Chan
- Research School of Biology, Australian National University, Acton, Canberra, Australia
| | - Boris Martinac
- Victor Chang Cardiac Research Institute, New South Wales, Australia; St Vincent's Clinical School, University of New South Wales, Darlinghurst, New South Wales, Australia
| | - Siewert J Marrink
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, the Netherlands
| | - Ben Corry
- Research School of Biology, Australian National University, Acton, Canberra, Australia.
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7
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Fantini J, Epand RM, Barrantes FJ. Cholesterol-Recognition Motifs in Membrane Proteins. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1135:3-25. [PMID: 31098808 DOI: 10.1007/978-3-030-14265-0_1] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The impact of cholesterol on the structure and function of membrane proteins was recognized several decades ago, but the molecular mechanisms underlying these effects have remained elusive. There appear to be multiple mechanisms by which cholesterol interacts with proteins. A complete understanding of cholesterol-sensing motifs is still undergoing refinement. Initially, cholesterol was thought to exert only non-specific effects on membrane fluidity. It was later shown that this lipid could specifically interact with membrane proteins and affect both their structure and function. In this article, we have summarized and critically analyzed our evolving understanding of the affinity, specificity and stereoselectivity of the interactions of cholesterol with membrane proteins. We review the different computational approaches that are currently used to identify cholesterol binding sites in membrane proteins and the biochemical logic that governs each type of site, including CRAC, CARC, SSD and amphipathic helix motifs. There are physiological implications of these cholesterol-recognition motifs for G-protein coupled receptors (GPCR) and ion channels, in membrane trafficking and membrane fusion (SNARE) proteins. There are also pathological implications of cholesterol binding to proteins involved in neurological disorders (Alzheimer, Parkinson, Creutzfeldt-Jakob) and HIV fusion. In each case, our discussion is focused on the key molecular aspects of the cholesterol and amino acid motifs in membrane-embedded regions of membrane proteins that define the physiologically relevant crosstalk between the two. Our understanding of the factors that determine if these motifs are functional in cholesterol binding will allow us enhanced predictive capabilities.
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Affiliation(s)
- Jacques Fantini
- INSERM UMR_S 1072, Marseille, France. .,Aix-Marseille Université, Marseille, France.
| | - Richard M Epand
- Department of Biochemistry and Biomedical Sciences, McMaster University, Health Sciences Centre, Hamilton, ON, Canada
| | - Francisco J Barrantes
- Laboratory of Molecular Neurobiology, Biomedical Research Institute (BIOMED), UCA-CONICET, Buenos Aires, Argentina
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8
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Ahyayauch H, García-Arribas AB, Sot J, González-Ramírez EJ, Busto JV, Monasterio BG, Jiménez-Rojo N, Contreras FX, Rendón-Ramírez A, Martin C, Alonso A, Goñi FM. Pb(II) Induces Scramblase Activation and Ceramide-Domain Generation in Red Blood Cells. Sci Rep 2018; 8:7456. [PMID: 29748552 PMCID: PMC5945622 DOI: 10.1038/s41598-018-25905-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 04/19/2018] [Indexed: 01/01/2023] Open
Abstract
The mechanisms of Pb(II) toxicity have been studied in human red blood cells using confocal microscopy, immunolabeling, fluorescence-activated cell sorting and atomic force microscopy. The process follows a sequence of events, starting with calcium entry, followed by potassium release, morphological change, generation of ceramide, lipid flip-flop and finally cell lysis. Clotrimazole blocks potassium channels and the whole process is inhibited. Immunolabeling reveals the generation of ceramide-enriched domains linked to a cell morphological change, while the use of a neutral sphingomyelinase inhibitor greatly delays the process after the morphological change, and lipid flip-flop is significantly reduced. These facts point to three major checkpoints in the process: first the upstream exchange of calcium and potassium, then ceramide domain formation, and finally the downstream scramblase activation necessary for cell lysis. In addition, partial non-cytotoxic cholesterol depletion of red blood cells accelerates the process as the morphological change occurs faster. Cholesterol could have a role in modulating the properties of the ceramide-enriched domains. This work is relevant in the context of cell death, heavy metal toxicity and sphingolipid signaling.
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Affiliation(s)
- Hasna Ahyayauch
- Instituto Biofisika (CSIC, UPV/EHU), 48080, Bilbao, Spain.,Institut Supérieur des Professions Infirmières et des Techniques de Santé, Rabat, Morocco.,Neuroendocrinology Unit, Laboratory of Genetics, Neuroendocrinology and Biotechnology, Faculty of Sciences, Ibn Tofail University, Kenitra, Morocco
| | - Aritz B García-Arribas
- Instituto Biofisika (CSIC, UPV/EHU), 48080, Bilbao, Spain.,Departamento de Bioquímica, University of the Basque Country (UPV/EHU), 48080, Bilbao, Spain
| | - Jesús Sot
- Instituto Biofisika (CSIC, UPV/EHU), 48080, Bilbao, Spain
| | - Emilio J González-Ramírez
- Instituto Biofisika (CSIC, UPV/EHU), 48080, Bilbao, Spain.,Departamento de Bioquímica, University of the Basque Country (UPV/EHU), 48080, Bilbao, Spain
| | - Jon V Busto
- Instituto Biofisika (CSIC, UPV/EHU), 48080, Bilbao, Spain.,Departamento de Bioquímica, University of the Basque Country (UPV/EHU), 48080, Bilbao, Spain
| | - Bingen G Monasterio
- Instituto Biofisika (CSIC, UPV/EHU), 48080, Bilbao, Spain.,Departamento de Bioquímica, University of the Basque Country (UPV/EHU), 48080, Bilbao, Spain
| | - Noemi Jiménez-Rojo
- Instituto Biofisika (CSIC, UPV/EHU), 48080, Bilbao, Spain.,Departamento de Bioquímica, University of the Basque Country (UPV/EHU), 48080, Bilbao, Spain.,NCCR Chemical Biology, Department of Biochemistry, University of Geneva, 1211, Geneva, Switzerland
| | - F Xabier Contreras
- Instituto Biofisika (CSIC, UPV/EHU), 48080, Bilbao, Spain.,Departamento de Bioquímica, University of the Basque Country (UPV/EHU), 48080, Bilbao, Spain
| | - Adela Rendón-Ramírez
- Instituto Biofisika (CSIC, UPV/EHU), 48080, Bilbao, Spain.,Departamento de Bioquímica, University of the Basque Country (UPV/EHU), 48080, Bilbao, Spain
| | - Cesar Martin
- Instituto Biofisika (CSIC, UPV/EHU), 48080, Bilbao, Spain.,Departamento de Bioquímica, University of the Basque Country (UPV/EHU), 48080, Bilbao, Spain
| | - Alicia Alonso
- Instituto Biofisika (CSIC, UPV/EHU), 48080, Bilbao, Spain.,Departamento de Bioquímica, University of the Basque Country (UPV/EHU), 48080, Bilbao, Spain
| | - Félix M Goñi
- Instituto Biofisika (CSIC, UPV/EHU), 48080, Bilbao, Spain. .,Departamento de Bioquímica, University of the Basque Country (UPV/EHU), 48080, Bilbao, Spain.
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9
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Palanirajan SK, Sivagnanam U, Murugan S, Gummadi SN. In vitro reconstitution and biochemical characterization of human phospholipid scramblase 3: phospholipid specificity and metal ion binding studies. Biol Chem 2018; 399:361-374. [DOI: 10.1515/hsz-2017-0309] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 12/14/2017] [Indexed: 01/11/2023]
Abstract
AbstractHuman phospholipid scramblase 3 (hPLSCR3) is a single pass transmembrane protein that plays a vital role in fat metabolism, mitochondrial function, structure, maintenance and apoptosis. The mechanism of action of scramblases remains still unknown, and the role of scramblases in phospholipid translocation is heavily debated. hPLSCR3 is the only member of scramblase family localized to mitochondria and is involved in cardiolipin translocation at the mitochondrial membrane. Direct biochemical evidence of phospholipid translocation by hPLSCR3 is yet to be reported. Functional assay in synthetic proteoliposomes upon Ca2+and Mg2+revealed that, apart from cardiolipin, recombinant hPLSCR3 translocates aminophospholipids such as NBD-PE and NBD-PS but not neutral phospholipids. Point mutation in hPLSCR3 (F258V) resulted in decreased Ca2+binding affinity. Functional assay with F258V-hPLSCR3 led to ~50% loss in scramblase activity in the presence of Ca2+and Mg2+. Metal ion-induced conformational changes were monitored by intrinsic tryptophan fluorescence, circular dichroism, surface hydrophobicity changes and aggregation studies. Our results revealed that Ca2+and Mg2+bind to hPLSCR3 and trigger conformational changes mediated by aggregation. In summary, we suggest that the metal ion-induced conformational change and the aggregation of the protein are essential for the phospholipid translocation by hPLSCR3.
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10
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Luévano-Martínez LA, Kowaltowski AJ. Topological characterization of the mitochondrial phospholipid scramblase 3. FEBS Lett 2017; 591:4056-4066. [DOI: 10.1002/1873-3468.12917] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 11/10/2017] [Accepted: 11/13/2017] [Indexed: 12/18/2022]
Affiliation(s)
- Luis Alberto Luévano-Martínez
- Departamento de Parasitologia; Instituto de Ciências Biomédicas; Universidade de São Paulo; Brazil
- Departamento de Bioquímica; Instituto de Química; Universidade de São Paulo; Brazil
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11
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Sivagnanam U, Palanirajan SK, Gummadi SN. The role of human phospholipid scramblases in apoptosis: An overview. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1864:2261-2271. [PMID: 28844836 DOI: 10.1016/j.bbamcr.2017.08.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 08/03/2017] [Accepted: 08/10/2017] [Indexed: 02/08/2023]
Abstract
Human phospholipid scramblases (hPLSCRs) are a family of four homologous single pass transmembrane proteins (hPLSCR1-4) initially identified as the proteins responsible for Ca2+ mediated bidirectional phospholipid translocation in plasma membrane. Though in-vitro assays had provided evidence, the role of hPLSCRs in phospholipid translocation is still debated. Recent reports revealed a new class of proteins, TMEM16 and Xkr8 to exhibit scramblase activity challenging the function of hPLSCRs. Apart from phospholipid scrambling, numerous reports have emphasized the multifunctional roles of hPLSCRs in key cellular processes including tumorigenesis, antiviral defense, protein and DNA interactions, transcriptional regulation and apoptosis. In this review, the role of hPLSCRs in mediating cell death through phosphatidylserine exposure, interaction with death receptors, cardiolipin exposure, heavy metal and radiation induced apoptosis and pathological apoptosis followed by their involvement in cancer cells are discussed. This review aims to connect the multifunctional characteristics of hPLSCRs to their decisive involvement in apoptotic pathways.
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Affiliation(s)
- Ulaganathan Sivagnanam
- Applied and Industrial Microbiology Laboratory, Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai 600 036, India
| | - Santosh Kumar Palanirajan
- Applied and Industrial Microbiology Laboratory, Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai 600 036, India
| | - Sathyanarayana N Gummadi
- Applied and Industrial Microbiology Laboratory, Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai 600 036, India.
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12
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Interactions stabilizing the C-terminal helix of human phospholipid scramblase 1 in lipid bilayers: A computational study. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:1200-1210. [DOI: 10.1016/j.bbamem.2017.03.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 03/09/2017] [Accepted: 03/29/2017] [Indexed: 12/19/2022]
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13
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Andraka N, Sánchez-Magraner L, García-Pacios M, Goñi FM, Arrondo JLR. The conformation of human phospholipid scramblase 1, as studied by infrared spectroscopy. Effects of calcium and detergent. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:1019-1028. [PMID: 28238818 DOI: 10.1016/j.bbamem.2017.02.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 02/18/2017] [Accepted: 02/22/2017] [Indexed: 12/18/2022]
Abstract
Human phospholipid scramblase 1 (SCR) is a membrane protein that catalyzes the transmembrane (flip-flop) motion of phospholipids. It can also exist in a non membrane-bound form in the nucleus, where it modulates several aspects of gene expression. Catalysis of phospholipid flip-flop requires the presence of millimolar Ca2+, and occurs in the absence of ATP. Membrane-bound SCR contains a C-terminal α-helical domain embedded in the membrane bilayer. The latter domain can be removed giving rise to a stable truncated mutant SCRΔ that is devoid of scramblase activity. In order to improve our understanding of SCR structure infrared spectra have been recorded of both the native and truncated forms, and the effects of adding Ca2+, or removing detergent, or thermally denaturing the protein have been observed. Under all conditions the main structural component of SCR/SCRΔ is a β-sheet. Removing the C-terminal 28 aa residues, which anchor SCR to the membrane, leads to a change in tertiary structure and an increased structural flexibility. The main effect of Ca2+ is an increase in the α/β ratio of secondary structure components, with a concomitant increase in the proportion of non-periodic structures. At least in SCRΔ, detergent (Zwittergent 3-12) decreases the structural flexibility, an effect somewhat opposite to that of increasing temperature. Thermal denaturation is affected by Ca2+, detergent, and by the presence or absence of the C-terminal domain, each of them influencing in different ways the denaturation pattern.
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Affiliation(s)
- Nagore Andraka
- Unidad de Biofísica (CSIC, UPV/EHU) and Departamento de Bioquímica, Universidad del País Vasco, P.O. Box 644, 48080 Bilbao, Spain
| | - Lissete Sánchez-Magraner
- Unidad de Biofísica (CSIC, UPV/EHU) and Departamento de Bioquímica, Universidad del País Vasco, P.O. Box 644, 48080 Bilbao, Spain
| | - Marcos García-Pacios
- Unidad de Biofísica (CSIC, UPV/EHU) and Departamento de Bioquímica, Universidad del País Vasco, P.O. Box 644, 48080 Bilbao, Spain
| | - Félix M Goñi
- Unidad de Biofísica (CSIC, UPV/EHU) and Departamento de Bioquímica, Universidad del País Vasco, P.O. Box 644, 48080 Bilbao, Spain
| | - José L R Arrondo
- Unidad de Biofísica (CSIC, UPV/EHU) and Departamento de Bioquímica, Universidad del País Vasco, P.O. Box 644, 48080 Bilbao, Spain.
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14
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Di Scala C, Baier CJ, Evans LS, Williamson PT, Fantini J, Barrantes FJ. Relevance of CARC and CRAC Cholesterol-Recognition Motifs in the Nicotinic Acetylcholine Receptor and Other Membrane-Bound Receptors. CURRENT TOPICS IN MEMBRANES 2017; 80:3-23. [DOI: 10.1016/bs.ctm.2017.05.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Arashiki N, Saito M, Koshino I, Kamata K, Hale J, Mohandas N, Manno S, Takakuwa Y. An Unrecognized Function of Cholesterol: Regulating the Mechanism Controlling Membrane Phospholipid Asymmetry. Biochemistry 2016; 55:3504-3513. [PMID: 27267274 PMCID: PMC5288641 DOI: 10.1021/acs.biochem.6b00407] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
An asymmetric distribution of phospholipids in the membrane bilayer is inseparable from physiological functions, including shape preservation and survival of erythrocytes, and by implication other cells. Aminophospholipids, notably phosphatidylserine (PS), are confined to the inner leaflet of the erythrocyte membrane lipid bilayer by the ATP-dependent flippase enzyme, ATP11C, counteracting the activity of an ATP-independent scramblase. Phospholipid scramblase 1 (PLSCR1), a single-transmembrane protein, was previously reported to possess scrambling activity in erythrocytes. However, its function was cast in doubt by the retention of scramblase activity in erythrocytes of knockout mice lacking this protein. We show that in the human erythrocyte PLSCR1 is the predominant scramblase and by reconstitution into liposomes that its activity resides in the transmembrane domain. At or below physiological intracellular calcium concentrations, total suppression of flippase activity nevertheless leaves the membrane asymmetry undisturbed. When liposomes or erythrocytes are depleted of cholesterol (a reversible process in the case of erythrocytes), PS quickly appears at the outer surface, implying that cholesterol acts in the cell as a powerful scramblase inhibitor. Thus, our results bring to light a previously unsuspected function of cholesterol in regulating phospholipid scrambling.
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Affiliation(s)
- Nobuto Arashiki
- Department of Biochemistry, School of Medicine, Tokyo Women's Medical University, 8-1 Kawada-Cho, Shinjuku-Ku, Tokyo 162-8666, Japan
| | - Masaki Saito
- Department of Biochemistry, School of Medicine, Tokyo Women's Medical University, 8-1 Kawada-Cho, Shinjuku-Ku, Tokyo 162-8666, Japan
| | - Ichiro Koshino
- Department of Biochemistry, School of Medicine, Tokyo Women's Medical University, 8-1 Kawada-Cho, Shinjuku-Ku, Tokyo 162-8666, Japan
| | - Kotoe Kamata
- Department of Biochemistry, School of Medicine, Tokyo Women's Medical University, 8-1 Kawada-Cho, Shinjuku-Ku, Tokyo 162-8666, Japan
- Department of Anesthesiology, School of Medicine, Tokyo Women's Medical University, 8-1 Kawada-Cho, Shinjuku-Ku, Tokyo 162-8666, Japan
| | - John Hale
- Red Cell Physiology Laboratory, New York Blood Center, New York, New York 10021, United States
| | - Narla Mohandas
- Red Cell Physiology Laboratory, New York Blood Center, New York, New York 10021, United States
| | - Sumie Manno
- Department of Biochemistry, School of Medicine, Tokyo Women's Medical University, 8-1 Kawada-Cho, Shinjuku-Ku, Tokyo 162-8666, Japan
| | - Yuichi Takakuwa
- Department of Biochemistry, School of Medicine, Tokyo Women's Medical University, 8-1 Kawada-Cho, Shinjuku-Ku, Tokyo 162-8666, Japan
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A mirror code for protein-cholesterol interactions in the two leaflets of biological membranes. Sci Rep 2016; 6:21907. [PMID: 26915987 PMCID: PMC4768152 DOI: 10.1038/srep21907] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 01/29/2016] [Indexed: 11/29/2022] Open
Abstract
Cholesterol controls the activity of a wide range of membrane receptors through specific interactions and identifying cholesterol recognition motifs is therefore critical for understanding signaling receptor function. The membrane-spanning domains of the paradigm neurotransmitter receptor for acetylcholine (AChR) display a series of cholesterol consensus domains (referred to as “CARC”). Here we use a combination of molecular modeling, lipid monolayer/mutational approaches and NMR spectroscopy to study the binding of cholesterol to a synthetic CARC peptide. The CARC-cholesterol interaction is of high affinity, lipid-specific, concentration-dependent, and sensitive to single-point mutations. The CARC motif is generally located in the outer membrane leaflet and its reverse sequence CRAC in the inner one. Their simultaneous presence within the same transmembrane domain obeys a “mirror code” controlling protein-cholesterol interactions in the outer and inner membrane leaflets. Deciphering this code enabled us to elaborate guidelines for the detection of cholesterol-binding motifs in any membrane protein. Several representative examples of neurotransmitter receptors and ABC transporters with the dual CARC/CRAC motifs are presented. The biological significance and potential clinical applications of the mirror code are discussed.
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Kodigepalli KM, Bowers K, Sharp A, Nanjundan M. Roles and regulation of phospholipid scramblases. FEBS Lett 2014; 589:3-14. [PMID: 25479087 DOI: 10.1016/j.febslet.2014.11.036] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Revised: 11/22/2014] [Accepted: 11/24/2014] [Indexed: 02/06/2023]
Abstract
Phospholipid scramblase activity is involved in the collapse of phospholipid (PL) asymmetry at the plasma membrane leading to externalization of phosphatidylserine. This activity is crucial for initiation of the blood coagulation cascade and for recognition/elimination of apoptotic cells by macrophages. Efforts to identify gene products associated with this activity led to the characterization of PL scramblase (PLSCR) and XKR family members which contribute to phosphatidylserine exposure in response to apoptotic stimuli. Meanwhile, TMEM16 family members were identified to externalize phosphatidylserine in response to elevated calcium in Scott syndrome platelets, which is critical for activation of the coagulation cascade. Herein, we report their mechanisms of gene regulation, molecular functions independent of their scrambling activity, and their potential roles in pathogenic conditions.
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Affiliation(s)
- Karthik M Kodigepalli
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, FL 33620, United States
| | - Kiah Bowers
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, FL 33620, United States
| | - Arielle Sharp
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, FL 33620, United States
| | - Meera Nanjundan
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, FL 33620, United States.
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