1
|
Lala T, Doan JK, Takatsu H, Hartzell HC, Shin HW, Hall RA. Phosphatidylserine exposure modulates adhesion GPCR BAI1 (ADGRB1) signaling activity. J Biol Chem 2022; 298:102685. [PMID: 36370845 PMCID: PMC9723945 DOI: 10.1016/j.jbc.2022.102685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 10/28/2022] [Accepted: 10/31/2022] [Indexed: 11/10/2022] Open
Abstract
Brain-specific angiogenesis inhibitor 1 (BAI1; also called ADGRB1 or B1) is an adhesion G protein-coupled receptor known from studies on macrophages to bind to phosphatidylserine (PS) on apoptotic cells via its N-terminal thrombospondin repeats. A separate body of work has shown that B1 regulates postsynaptic function and dendritic spine morphology via signaling pathways involving Rac and Rho. However, it is unknown if PS binding by B1 has any effect on the receptor's signaling activity. To shed light on this subject, we studied G protein-dependent signaling by B1 in the absence and presence of coexpression with the PS flippase ATP11A in human embryonic kidney 293T cells. ATP11A expression reduced the amount of PS exposed extracellularly and also strikingly reduced the signaling activity of coexpressed full-length B1 but not a truncated version of the receptor lacking the thrombospondin repeats. Further experiments with an inactive mutant of ATP11A showed that the PS flippase function of ATP11A was required for modulation of B1 signaling. In coimmunoprecipitation experiments, we made the surprising finding that ATP11A not only modulates B1 signaling but also forms complexes with B1. Parallel studies in which PS in the outer leaflet was reduced by an independent method, deletion of the gene encoding the endogenous lipid scramblase anoctamin 6 (ANO6), revealed that this manipulation also markedly reduced B1 signaling. These findings demonstrate that B1 signaling is modulated by PS exposure and suggest a model in which B1 serves as a PS sensor at synapses and in other cellular contexts.
Collapse
Affiliation(s)
- Trisha Lala
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Juleva K Doan
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Hiroyuki Takatsu
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - H Criss Hartzell
- Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Hye-Won Shin
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Randy A Hall
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, Georgia, USA.
| |
Collapse
|
2
|
Argañaraz GA, Palmeira JDF, Argañaraz ER. Phosphatidylserine inside out: a possible underlying mechanism in the inflammation and coagulation abnormalities of COVID-19. Cell Commun Signal 2020; 18:190. [PMID: 33357215 PMCID: PMC7765775 DOI: 10.1186/s12964-020-00687-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 11/23/2020] [Indexed: 12/22/2022] Open
Abstract
The rapid ability of SARS-CoV-2 to spread among humans, along with the clinical complications of coronavirus disease 2019-COVID-19, have represented a significant challenge to the health management systems worldwide. The acute inflammation and coagulation abnormalities appear as the main causes for thousands of deaths worldwide. The intense inflammatory response could be involved with the formation of thrombi. For instance, the presence of uncleaved large multimers of von Willebrand (vWF), due to low ADAMTS13 activity in plasma could be explained by the inhibitory action of pro-inflammatory molecules such as IL-1β and C reactive protein. In addition, the damage to endothelial cells after viral infection and/or activation of endothelium by pro-inflammatory cytokines, such as IL-1β, IL-6, IFN-γ, IL-8, and TNF-α induces platelets and monocyte aggregation in the vascular wall and expression of tissue factor (TF). The TF expression may culminate in the formation of thrombi, and activation of cascade by the extrinsic pathway by association with factor VII. In this scenario, the phosphatidylserine-PtdSer exposure on the outer leaflet of the cell membrane as consequence of viral infection emerges as another possible underlying mechanism to acute immune inflammatory response and activation of coagulation cascade. The PtdSer exposure may be an important mechanism related to ADAM17-mediated ACE2, TNF-α, EGFR and IL-6R shedding, and the activation of TF on the surface of infected endothelial cells. In this review, we address the underlying mechanisms involved in the pathophysiology of inflammation and coagulation abnormalities. Moreover, we introduce key biochemical and pathophysiological concepts that support the possible participation of PtdSer exposure on the outer side of the SARS-CoV-2 infected cells membrane, in the pathophysiology of COVID-19. Video Abstract.
Collapse
Affiliation(s)
- Gustavo A. Argañaraz
- Laboratory of Molecular Neurovirology, Faculty of Health Science, University of Brasília, Brasília, 70910-900 Brazil
| | - Julys da Fonseca Palmeira
- Laboratory of Molecular Neurovirology, Faculty of Health Science, University of Brasília, Brasília, 70910-900 Brazil
| | - Enrique R. Argañaraz
- Laboratory of Molecular Neurovirology, Faculty of Health Science, University of Brasília, Brasília, 70910-900 Brazil
| |
Collapse
|
3
|
Zhao H, Wang T. PE homeostasis rebalanced through mitochondria-ER lipid exchange prevents retinal degeneration in Drosophila. PLoS Genet 2020; 16:e1009070. [PMID: 33064773 PMCID: PMC7592913 DOI: 10.1371/journal.pgen.1009070] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 10/28/2020] [Accepted: 08/21/2020] [Indexed: 02/06/2023] Open
Abstract
The major glycerophospholipid phosphatidylethanolamine (PE) in the nervous system is essential for neural development and function. There are two major PE synthesis pathways, the CDP-ethanolamine pathway in the endoplasmic reticulum (ER) and the phosphatidylserine decarboxylase (PSD) pathway in mitochondria. However, the role played by mitochondrial PE synthesis in maintaining cellular PE homeostasis is unknown. Here, we show that Drosophila pect (phosphoethanolamine cytidylyltransferase) mutants lacking the CDP-ethanolamine pathway, exhibited alterations in phospholipid composition, defective phototransduction, and retinal degeneration. Induction of the PSD pathway fully restored levels and composition of cellular PE, thus rescued the retinal degeneration and defective visual responses in pect mutants. Disrupting lipid exchange between mitochondria and ER blocked the ability of PSD to rescue pect mutant phenotypes. These findings provide direct evidence that the synthesis of PE in mitochondria contributes to cellular PE homeostasis, and suggest the induction of mitochondrial PE synthesis as a promising therapeutic approach for disorders associated with PE deficiency.
Collapse
Affiliation(s)
- Haifang Zhao
- National Institute of Biological Sciences, Beijing, China
| | - Tao Wang
- National Institute of Biological Sciences, Beijing, China
- Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, China
| |
Collapse
|
4
|
Li T, Chiou B, Gilman CK, Luo R, Koshi T, Yu D, Oak HC, Giera S, Johnson‐Venkatesh E, Muthukumar AK, Stevens B, Umemori H, Piao X. A splicing isoform of GPR56 mediates microglial synaptic refinement via phosphatidylserine binding. EMBO J 2020; 39:e104136. [PMID: 32452062 PMCID: PMC7429740 DOI: 10.15252/embj.2019104136] [Citation(s) in RCA: 85] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 04/20/2020] [Accepted: 04/22/2020] [Indexed: 12/31/2022] Open
Abstract
Developmental synaptic remodeling is important for the formation of precise neural circuitry, and its disruption has been linked to neurodevelopmental disorders such as autism and schizophrenia. Microglia prune synapses, but integration of this synapse pruning with overlapping and concurrent neurodevelopmental processes, remains elusive. Adhesion G protein-coupled receptor ADGRG1/GPR56 controls multiple aspects of brain development in a cell type-specific manner: In neural progenitor cells, GPR56 regulates cortical lamination, whereas in oligodendrocyte progenitor cells, GPR56 controls developmental myelination and myelin repair. Here, we show that microglial GPR56 maintains appropriate synaptic numbers in several brain regions in a time- and circuit-dependent fashion. Phosphatidylserine (PS) on presynaptic elements binds GPR56 in a domain-specific manner, and microglia-specific deletion of Gpr56 leads to increased synapses as a result of reduced microglial engulfment of PS+ presynaptic inputs. Remarkably, a particular alternatively spliced isoform of GPR56 is selectively required for microglia-mediated synaptic pruning. Our present data provide a ligand- and isoform-specific mechanism underlying microglial GPR56-mediated synapse pruning in the context of complex neurodevelopmental processes.
Collapse
Affiliation(s)
- Tao Li
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell ResearchUniversity of California, San Francisco (UCSF)San FranciscoCAUSA
- Department of MedicineBoston Children's Hospital and Harvard Medical SchoolBostonMAUSA
| | - Brian Chiou
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell ResearchUniversity of California, San Francisco (UCSF)San FranciscoCAUSA
| | - Casey K Gilman
- Department of MedicineBoston Children's Hospital and Harvard Medical SchoolBostonMAUSA
| | - Rong Luo
- Department of MedicineBoston Children's Hospital and Harvard Medical SchoolBostonMAUSA
| | - Tatsuhiro Koshi
- Department of MedicineBoston Children's Hospital and Harvard Medical SchoolBostonMAUSA
| | - Diankun Yu
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell ResearchUniversity of California, San Francisco (UCSF)San FranciscoCAUSA
| | - Hayeon C Oak
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell ResearchUniversity of California, San Francisco (UCSF)San FranciscoCAUSA
| | - Stefanie Giera
- Department of MedicineBoston Children's Hospital and Harvard Medical SchoolBostonMAUSA
| | | | - Allie K Muthukumar
- F. M. Kirby Neurobiology CenterChildren's HospitalHarvard Medical SchoolBostonMAUSA
| | - Beth Stevens
- F. M. Kirby Neurobiology CenterChildren's HospitalHarvard Medical SchoolBostonMAUSA
- Howard Hughes Medical InstituteBoston Children's HospitalBostonMAUSA
| | - Hisashi Umemori
- F. M. Kirby Neurobiology CenterChildren's HospitalHarvard Medical SchoolBostonMAUSA
| | - Xianhua Piao
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell ResearchUniversity of California, San Francisco (UCSF)San FranciscoCAUSA
- Department of MedicineBoston Children's Hospital and Harvard Medical SchoolBostonMAUSA
- F. M. Kirby Neurobiology CenterChildren's HospitalHarvard Medical SchoolBostonMAUSA
- Weill Institute for NeuroscienceUniversity of California, San Francisco (UCSF)San FranciscoCAUSA
- Division of NeonatologyDepartment of PediatricsUniversity of California, San Francisco (UCSF)San FranciscoCAUSA
- Newborn Brain Research InstituteUniversity of California, San Francisco (UCSF)San FranciscoCAUSA
| |
Collapse
|
5
|
Scott‐Hewitt N, Perrucci F, Morini R, Erreni M, Mahoney M, Witkowska A, Carey A, Faggiani E, Schuetz LT, Mason S, Tamborini M, Bizzotto M, Passoni L, Filipello F, Jahn R, Stevens B, Matteoli M. Local externalization of phosphatidylserine mediates developmental synaptic pruning by microglia. EMBO J 2020; 39:e105380. [PMID: 32657463 PMCID: PMC7429741 DOI: 10.15252/embj.2020105380] [Citation(s) in RCA: 196] [Impact Index Per Article: 49.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 06/05/2020] [Accepted: 06/15/2020] [Indexed: 12/21/2022] Open
Abstract
Neuronal circuit assembly requires the fine balance between synapse formation and elimination. Microglia, through the elimination of supernumerary synapses, have an established role in this process. While the microglial receptor TREM2 and the soluble complement proteins C1q and C3 are recognized as key players, the neuronal molecular components that specify synapses to be eliminated are still undefined. Here, we show that exposed phosphatidylserine (PS) represents a neuronal "eat-me" signal involved in microglial-mediated pruning. In hippocampal neuron and microglia co-cultures, synapse elimination can be partially prevented by blocking accessibility of exposed PS using Annexin V or through microglial loss of TREM2. In vivo, PS exposure at both hippocampal and retinogeniculate synapses and engulfment of PS-labeled material by microglia occurs during established developmental periods of microglial-mediated synapse elimination. Mice deficient in C1q, which fail to properly refine retinogeniculate connections, have elevated presynaptic PS exposure and reduced PS engulfment by microglia. These data provide mechanistic insight into microglial-mediated synapse pruning and identify a novel role of developmentally regulated neuronal PS exposure that is common among developing brain structures.
Collapse
Affiliation(s)
- Nicole Scott‐Hewitt
- F.M. Kirby Center for NeurobiologyBoston Children's HospitalBostonMAUSA
- Stanley Center for Psychiatric ResearchThe Broad Institute of MIT and HarvardCambridgeMAUSA
| | - Fabio Perrucci
- Laboratory of Pharmacology and Brain PathologyNeurocenterHumanitas Clinical and Research Center ‐ IRCCSRozzano (MI)Italy
- Department of Biomedical SciencesHumanitas UniversityPieve Emanuele (MI)Italy
| | - Raffaella Morini
- Laboratory of Pharmacology and Brain PathologyNeurocenterHumanitas Clinical and Research Center ‐ IRCCSRozzano (MI)Italy
| | - Marco Erreni
- Unit of Advanced Optical MicroscopyHumanitas Clinical and Research Center ‐ IRCCSRozzano (MI)Italy
| | - Matthew Mahoney
- F.M. Kirby Center for NeurobiologyBoston Children's HospitalBostonMAUSA
| | - Agata Witkowska
- Laboratory of NeurobiologyMax Planck Institute for Biophysical ChemistryGöttingenGermany
- Department of Molecular Pharmacology and Cell BiologyLeibniz‐Forschungsinstitut für Molekulare Pharmakologie (FMP)BerlinGermany
| | - Alanna Carey
- F.M. Kirby Center for NeurobiologyBoston Children's HospitalBostonMAUSA
| | - Elisa Faggiani
- Laboratory of Pharmacology and Brain PathologyNeurocenterHumanitas Clinical and Research Center ‐ IRCCSRozzano (MI)Italy
| | | | - Sydney Mason
- F.M. Kirby Center for NeurobiologyBoston Children's HospitalBostonMAUSA
| | - Matteo Tamborini
- Laboratory of Pharmacology and Brain PathologyNeurocenterHumanitas Clinical and Research Center ‐ IRCCSRozzano (MI)Italy
| | - Matteo Bizzotto
- Department of Biomedical SciencesHumanitas UniversityPieve Emanuele (MI)Italy
| | - Lorena Passoni
- Laboratory of Pharmacology and Brain PathologyNeurocenterHumanitas Clinical and Research Center ‐ IRCCSRozzano (MI)Italy
| | - Fabia Filipello
- Laboratory of Pharmacology and Brain PathologyNeurocenterHumanitas Clinical and Research Center ‐ IRCCSRozzano (MI)Italy
- Department of Biomedical SciencesHumanitas UniversityPieve Emanuele (MI)Italy
- Present address:
Department of NeurologyWashington UniversitySt. LouisMOUSA
| | - Reinhard Jahn
- Laboratory of NeurobiologyMax Planck Institute for Biophysical ChemistryGöttingenGermany
- University of GöttingenGöttingenGermany
| | - Beth Stevens
- F.M. Kirby Center for NeurobiologyBoston Children's HospitalBostonMAUSA
- Stanley Center for Psychiatric ResearchThe Broad Institute of MIT and HarvardCambridgeMAUSA
- Howard Hughes Medical InstituteBoston Children's HospitalBostonMAUSA
| | - Michela Matteoli
- Laboratory of Pharmacology and Brain PathologyNeurocenterHumanitas Clinical and Research Center ‐ IRCCSRozzano (MI)Italy
- CNR Institute of NeuroscienceMilanoItaly
| |
Collapse
|
6
|
Rival CM, Xu W, Shankman LS, Morioka S, Arandjelovic S, Lee CS, Wheeler KM, Smith RP, Haney LB, Isakson BE, Purcell S, Lysiak JJ, Ravichandran KS. Phosphatidylserine on viable sperm and phagocytic machinery in oocytes regulate mammalian fertilization. Nat Commun 2019; 10:4456. [PMID: 31575859 PMCID: PMC6773685 DOI: 10.1038/s41467-019-12406-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 08/29/2019] [Indexed: 01/06/2023] Open
Abstract
Fertilization is essential for species survival. Although Izumo1 and Juno are critical for initial interaction between gametes, additional molecules necessary for sperm:egg fusion on both the sperm and the oocyte remain to be defined. Here, we show that phosphatidylserine (PtdSer) is exposed on the head region of viable and motile sperm, with PtdSer exposure progressively increasing during sperm transit through the epididymis. Functionally, masking phosphatidylserine on sperm via three different approaches inhibits fertilization. On the oocyte, phosphatidylserine recognition receptors BAI1, CD36, Tim-4, and Mer-TK contribute to fertilization. Further, oocytes lacking the cytoplasmic ELMO1, or functional disruption of RAC1 (both of which signal downstream of BAI1/BAI3), also affect sperm entry into oocytes. Intriguingly, mammalian sperm could fuse with skeletal myoblasts, requiring PtdSer on sperm and BAI1/3, ELMO2, RAC1 in myoblasts. Collectively, these data identify phosphatidylserine on viable sperm and PtdSer recognition receptors on oocytes as key players in sperm:egg fusion.
Collapse
Affiliation(s)
- Claudia M Rival
- The Center for Cell Clearance, School of Medicine, University of Virginia, 1340 Jefferson Park Avenue, Pinn Hall, Charlottesville, VA, 22903, USA
- Department of Microbiology, Immunology, and Cancer Biology, School of Medicine, University of Virginia, 1340 Jefferson Park Avenue, Pinn Hall, Charlottesville, VA, 22903, USA
- Department of Urology, School of Medicine, University of Virginia, 1340 Jefferson Park Avenue, Pinn Hall, Charlottesville, VA, 22903, USA
| | - Wenhao Xu
- Department of Microbiology, Immunology, and Cancer Biology, School of Medicine, University of Virginia, 1340 Jefferson Park Avenue, Pinn Hall, Charlottesville, VA, 22903, USA
| | - Laura S Shankman
- The Center for Cell Clearance, School of Medicine, University of Virginia, 1340 Jefferson Park Avenue, Pinn Hall, Charlottesville, VA, 22903, USA
- Department of Microbiology, Immunology, and Cancer Biology, School of Medicine, University of Virginia, 1340 Jefferson Park Avenue, Pinn Hall, Charlottesville, VA, 22903, USA
| | - Sho Morioka
- The Center for Cell Clearance, School of Medicine, University of Virginia, 1340 Jefferson Park Avenue, Pinn Hall, Charlottesville, VA, 22903, USA
- Department of Microbiology, Immunology, and Cancer Biology, School of Medicine, University of Virginia, 1340 Jefferson Park Avenue, Pinn Hall, Charlottesville, VA, 22903, USA
| | - Sanja Arandjelovic
- The Center for Cell Clearance, School of Medicine, University of Virginia, 1340 Jefferson Park Avenue, Pinn Hall, Charlottesville, VA, 22903, USA
- Department of Microbiology, Immunology, and Cancer Biology, School of Medicine, University of Virginia, 1340 Jefferson Park Avenue, Pinn Hall, Charlottesville, VA, 22903, USA
| | - Chang Sup Lee
- The Center for Cell Clearance, School of Medicine, University of Virginia, 1340 Jefferson Park Avenue, Pinn Hall, Charlottesville, VA, 22903, USA
- Department of Microbiology, Immunology, and Cancer Biology, School of Medicine, University of Virginia, 1340 Jefferson Park Avenue, Pinn Hall, Charlottesville, VA, 22903, USA
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Gyeongsang National University, 501 Jinju-daero, Jinju, Gyeongnam, 52828, Republic of Korea
| | - Karen M Wheeler
- Department of Urology, School of Medicine, University of Virginia, 1340 Jefferson Park Avenue, Pinn Hall, Charlottesville, VA, 22903, USA
| | - Ryan P Smith
- Department of Urology, School of Medicine, University of Virginia, 1340 Jefferson Park Avenue, Pinn Hall, Charlottesville, VA, 22903, USA
| | - Lisa B Haney
- The Center for Cell Clearance, School of Medicine, University of Virginia, 1340 Jefferson Park Avenue, Pinn Hall, Charlottesville, VA, 22903, USA
- Department of Microbiology, Immunology, and Cancer Biology, School of Medicine, University of Virginia, 1340 Jefferson Park Avenue, Pinn Hall, Charlottesville, VA, 22903, USA
| | - Brant E Isakson
- Department of Molecular Physiology and Biological Physics, School of Medicine, University of Virginia, 1340 Jefferson Park Avenue, Pinn Hall, Charlottesville, VA, 22903, USA
| | - Scott Purcell
- Reproductive Medicine and Surgery Center of Virginia, 595 Martha Jefferson Dr., Charlottesville, VA, 22911, USA
| | - Jeffrey J Lysiak
- The Center for Cell Clearance, School of Medicine, University of Virginia, 1340 Jefferson Park Avenue, Pinn Hall, Charlottesville, VA, 22903, USA.
- Department of Urology, School of Medicine, University of Virginia, 1340 Jefferson Park Avenue, Pinn Hall, Charlottesville, VA, 22903, USA.
| | - Kodi S Ravichandran
- The Center for Cell Clearance, School of Medicine, University of Virginia, 1340 Jefferson Park Avenue, Pinn Hall, Charlottesville, VA, 22903, USA.
- Department of Microbiology, Immunology, and Cancer Biology, School of Medicine, University of Virginia, 1340 Jefferson Park Avenue, Pinn Hall, Charlottesville, VA, 22903, USA.
- Department of Biomedical Molecular Biology, Ghent University, and the UGent-VIB Center for Inflammation Research, Technologiepark 71, 9052, Ghent, Belgium.
| |
Collapse
|
7
|
Kubátová Z, Pejchar P, Potocký M, Sekereš J, Žárský V, Kulich I. Arabidopsis Trichome Contains Two Plasma Membrane Domains with Different Lipid Compositions Which Attract Distinct EXO70 Subunits. Int J Mol Sci 2019; 20:ijms20153803. [PMID: 31382643 PMCID: PMC6695903 DOI: 10.3390/ijms20153803] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 07/29/2019] [Accepted: 08/01/2019] [Indexed: 12/23/2022] Open
Abstract
Plasma membrane (PM) lipid composition and domain organization are modulated by polarized exocytosis. Conversely, targeting of secretory vesicles at specific domains in the PM is carried out by exocyst complexes, which contain EXO70 subunits that play a significant role in the final recognition of the target membrane. As we have shown previously, a mature Arabidopsis trichome contains a basal domain with a thin cell wall and an apical domain with a thick secondary cell wall, which is developed in an EXO70H4-dependent manner. These domains are separated by a cell wall structure named the Ortmannian ring. Using phospholipid markers, we demonstrate that there are two distinct PM domains corresponding to these cell wall domains. The apical domain is enriched in phosphatidic acid (PA) and phosphatidylserine, with an undetectable amount of phosphatidylinositol 4,5-bisphosphate (PIP2), whereas the basal domain is PIP2-rich. While the apical domain recruits EXO70H4, the basal domain recruits EXO70A1, which corresponds to the lipid-binding capacities of these two paralogs. Loss of EXO70H4 results in a loss of the Ortmannian ring border and decreased apical PA accumulation, which causes the PA and PIP2 domains to merge together. Using transmission electron microscopy, we describe these accumulations as a unique anatomical feature of the apical cell wall-radially distributed rod-shaped membranous pockets, where both EXO70H4 and lipid markers are immobilized.
Collapse
Affiliation(s)
- Zdeňka Kubátová
- Department of Experimental Plant Biology, Faculty of Science, Charles University, 12800 Prague, Czech Republic
| | - Přemysl Pejchar
- Department of Experimental Plant Biology, Faculty of Science, Charles University, 12800 Prague, Czech Republic
- Institute of Experimental Botany, Czech Academy of Sciences, 165 02 Prague, Czech Republic
| | - Martin Potocký
- Department of Experimental Plant Biology, Faculty of Science, Charles University, 12800 Prague, Czech Republic
- Institute of Experimental Botany, Czech Academy of Sciences, 165 02 Prague, Czech Republic
| | - Juraj Sekereš
- Institute of Experimental Botany, Czech Academy of Sciences, 165 02 Prague, Czech Republic
| | - Viktor Žárský
- Department of Experimental Plant Biology, Faculty of Science, Charles University, 12800 Prague, Czech Republic
- Institute of Experimental Botany, Czech Academy of Sciences, 165 02 Prague, Czech Republic
| | - Ivan Kulich
- Department of Experimental Plant Biology, Faculty of Science, Charles University, 12800 Prague, Czech Republic.
| |
Collapse
|
8
|
Mizuike A, Kobayashi S, Rikukawa T, Ohta A, Horiuchi H, Fukuda R. Suppression of respiratory growth defect of mitochondrial phosphatidylserine decarboxylase deficient mutant by overproduction of Sfh1, a Sec14 homolog, in yeast. PLoS One 2019; 14:e0215009. [PMID: 30958856 PMCID: PMC6453485 DOI: 10.1371/journal.pone.0215009] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Accepted: 03/25/2019] [Indexed: 12/15/2022] Open
Abstract
Interorganelle phospholipid transfer is critical for eukaryotic membrane biogenesis. In the yeast Saccharomyces cerevisiae, phosphatidylserine (PS) synthesized by PS synthase, Pss1, in the endoplasmic reticulum (ER) is decarboxylated to phosphatidylethanolamine (PE) by PS decarboxylase, Psd1, in the ER and mitochondria or by Psd2 in the endosome, Golgi, and/or vacuole, but the mechanism of interorganelle PS transport remains to be elucidated. Here we report that Sfh1, a member of Sec14 family proteins of S. cerevisiae, possesses the ability to enhance PE production by Psd2. Overexpression of SFH1 in the strain defective in Psd1 restored its growth on non-fermentable carbon sources and increased the intracellular and mitochondrial PE levels. Sfh1 was found to bind various phospholipids, including PS, in vivo. Bacterially expressed and purified Sfh1 was suggested to have the ability to transport fluorescently labeled PS between liposomes by fluorescence dequenching assay in vitro. Biochemical subcellular fractionation suggested that a fraction of Sfh1 localizes to the endosome, Golgi, and/or vacuole. We propose a model that Sfh1 promotes PE production by Psd2 by transferring phospholipids between the ER and endosome.
Collapse
Affiliation(s)
- Aya Mizuike
- Department of Biotechnology, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Shingo Kobayashi
- Department of Biotechnology, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Takashi Rikukawa
- Department of Biotechnology, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Akinori Ohta
- Department of Biological Chemistry, College of Bioscience and Biotechnology, Chubu University, Kasugai, Aichi, Japan
| | - Hiroyuki Horiuchi
- Department of Biotechnology, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
- Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Ryouichi Fukuda
- Department of Biotechnology, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
- Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
- * E-mail:
| |
Collapse
|
9
|
Koval O, Kochneva G, Tkachenko A, Troitskaya O, Sivolobova G, Grazhdantseva A, Nushtaeva A, Kuligina E, Richter V. Recombinant Vaccinia Viruses Coding Transgenes of Apoptosis-Inducing Proteins Enhance Apoptosis But Not Immunogenicity of Infected Tumor Cells. Biomed Res Int 2017; 2017:3620510. [PMID: 28951871 PMCID: PMC5603130 DOI: 10.1155/2017/3620510] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 07/17/2017] [Accepted: 07/26/2017] [Indexed: 12/16/2022]
Abstract
Genetic modifications of the oncolytic vaccinia virus (VV) improve selective tumor cell infection and death, as well as activation of antitumor immunity. We have engineered a double recombinant VV, coding human GM-CSF, and apoptosis-inducing protein apoptin (VV-GMCSF-Apo) for comparing with the earlier constructed double recombinant VV-GMCSF-Lact, coding another apoptosis-inducing protein, lactaptin, which activated different cell death pathways than apoptin. We showed that both these recombinant VVs more considerably activated a set of critical apoptosis markers in infected cells than the recombinant VV coding GM-CSF alone (VV-GMCSF-dGF): these were phosphatidylserine externalization, caspase-3 and caspase-7 activation, DNA fragmentation, and upregulation of proapoptotic protein BAX. However, only VV-GMCSF-Lact efficiently decreased the mitochondrial membrane potential of infected cancer cells. Investigating immunogenic cell death markers in cancer cells infected with recombinant VVs, we demonstrated that all tested recombinant VVs were efficient in calreticulin and HSP70 externalization, decrease of cellular HMGB1, and ATP secretion. The comparison of antitumor activity against advanced MDA-MB-231 tumor revealed that both recombinants VV-GMCSF-Lact and VV-GMCSF-Apo efficiently delay tumor growth. Our results demonstrate that the composition of GM-CSF and apoptosis-inducing proteins in the VV genome is very efficient tool for specific killing of cancer cells and for activation of antitumor immunity.
Collapse
Affiliation(s)
- Olga Koval
- Department of Biotechnology, Institute of Chemical Biology and Fundamental Medicine, SB RAS, Novosibirsk, Russia
- Department of Natural Sciences, Novosibirsk State University, Novosibirsk, Russia
| | - Galina Kochneva
- Department of Viral Hepatitis, State Research Center of Virology and Biotechnology “Vector”, Rospotrebnadzor, Koltsovo, Russia
| | - Anastasiya Tkachenko
- Department of Biotechnology, Institute of Chemical Biology and Fundamental Medicine, SB RAS, Novosibirsk, Russia
| | - Olga Troitskaya
- Department of Biotechnology, Institute of Chemical Biology and Fundamental Medicine, SB RAS, Novosibirsk, Russia
- Department of Natural Sciences, Novosibirsk State University, Novosibirsk, Russia
| | - Galina Sivolobova
- Department of Viral Hepatitis, State Research Center of Virology and Biotechnology “Vector”, Rospotrebnadzor, Koltsovo, Russia
| | - Antonina Grazhdantseva
- Department of Viral Hepatitis, State Research Center of Virology and Biotechnology “Vector”, Rospotrebnadzor, Koltsovo, Russia
| | - Anna Nushtaeva
- Department of Biotechnology, Institute of Chemical Biology and Fundamental Medicine, SB RAS, Novosibirsk, Russia
| | - Elena Kuligina
- Department of Biotechnology, Institute of Chemical Biology and Fundamental Medicine, SB RAS, Novosibirsk, Russia
| | - Vladimir Richter
- Department of Biotechnology, Institute of Chemical Biology and Fundamental Medicine, SB RAS, Novosibirsk, Russia
| |
Collapse
|
10
|
Fujii T, Sakata A, Nishimura S, Eto K, Nagata S. TMEM16F is required for phosphatidylserine exposure and microparticle release in activated mouse platelets. Proc Natl Acad Sci U S A 2015; 112:12800-5. [PMID: 26417084 PMCID: PMC4611630 DOI: 10.1073/pnas.1516594112] [Citation(s) in RCA: 163] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Phosphatidylserine (PtdSer) exposure on the surface of activated platelets requires the action of a phospholipid scramblase(s), and serves as a scaffold for the assembly of the tenase and prothrombinase complexes involved in blood coagulation. Here, we found that the activation of mouse platelets with thrombin/collagen or Ca(2+) ionophore at 20 °C induces PtdSer exposure without compromising plasma membrane integrity. Among five transmembrane protein 16 (TMEM16) members that support Ca(2+)-dependent phospholipid scrambling, TMEM16F was the only one that showed high expression in mouse platelets. Platelets from platelet-specific TMEM16F-deficient mice exhibited defects in activation-induced PtdSer exposure and microparticle shedding, although α-granule and dense granule release remained intact. The rate of tissue factor-induced thrombin generation by TMEM16F-deficient platelets was severely reduced, whereas thrombin-induced clot retraction was unaffected. The imaging of laser-induced thrombus formation in whole animals showed that PtdSer exposure on aggregated platelets was TMEM16F-dependent in vivo. The phenotypes of the platelet-specific TMEM16F-null mice resemble those of patients with Scott syndrome, a mild bleeding disorder, indicating that these mice may provide a useful model for human Scott syndrome.
Collapse
Affiliation(s)
- Toshihiro Fujii
- Laboratory of Biochemistry & Immunology, Immunology Frontier Research Center, Osaka University, Osaka 565-0871, Japan; Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Saitama 332-0012, Japan
| | - Asuka Sakata
- Center for Molecular Medicine, Jichi Medical University, Tochigi 329-0498, Japan
| | - Satoshi Nishimura
- Center for Molecular Medicine, Jichi Medical University, Tochigi 329-0498, Japan; Department of Cardiovascular Medicine, The University of Tokyo, Tokyo 113-0033, Japan
| | - Koji Eto
- Department of Clinical Application, Center for iPS Cell Research and Application, Kyoto University, Kyoto 606-8507, Japan
| | - Shigekazu Nagata
- Laboratory of Biochemistry & Immunology, Immunology Frontier Research Center, Osaka University, Osaka 565-0871, Japan; Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Saitama 332-0012, Japan;
| |
Collapse
|
11
|
Korneenko TV, Pestov NB, Okkelman IA, Modyanov NN, Shakhparonov MI. [P4-ATP-ase Atp8b1/FIC1: structural properties and (patho)physiological functions]. Bioorg Khim 2015; 41:3-12. [PMID: 26050466 DOI: 10.1134/s1068162015010070] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
P4-ATP-ases comprise an interesting family among P-type ATP-ases, since they are thought to play a major role in the transfer of phospholipids such as phosphatydylserine from the outer leaflet to the inner leaflet. Isoforms of P4-ATP-ases are partially interchangeable but peculiarities of tissue-specific expression of their genes, intracellular localization of proteins, as well as regulatory pathways lead to the fact that, on the organismal level, serious pathologies may develop in the presence of structural abnormalities in certain isoforms. Among P4-ATP-ases a special place is occupied by ATP8B1, for which several mutations are known that lead to serious hereditary diseases: two forms of congenital cholestasis (PFIC1 or Byler disease and benign recurrent intrahepatic cholestasis) with extraliver symptoms such as sensorineural hearing loss. The physiological function of the Atp8b1/FIC1 protein is known in general outline: it is responsible for transport of certain phospholipids (phosphatydylserine, cardiolipin) for the outer monolayer of the plasma membrane to the inner one. It is well known that perturbation of membrane asymmetry, caused by the lack of Atp8B1 activity, leads to death of hairy cells of the inner ear, dysfunction of bile acid transport in liver-cells that causes cirrhosis. It is also probable that insufficient activity of Atp8b1/FIC1 increases susceptibility to bacterial pneumonia.Regulatory pathways of Atp8b1/FIC1 activity in vivo remain to be insufficiently studied and this opens novel perspectives for research in this field that may allow better understanding of molecular processes behind the development of certain pathologies and to reveal novel therapeutical targets.
Collapse
|
12
|
Xie LJ, Chen QF, Chen MX, Yu LJ, Huang L, Chen L, Wang FZ, Xia FN, Zhu TR, Wu JX, Yin J, Liao B, Shi J, Zhang JH, Aharoni A, Yao N, Shu W, Xiao S. Unsaturation of very-long-chain ceramides protects plant from hypoxia-induced damages by modulating ethylene signaling in Arabidopsis. PLoS Genet 2015; 11:e1005143. [PMID: 25822663 PMCID: PMC4379176 DOI: 10.1371/journal.pgen.1005143] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Accepted: 03/12/2015] [Indexed: 01/16/2023] Open
Abstract
Lipid remodeling is crucial for hypoxic tolerance in animals, whilst little is known about the hypoxia-induced lipid dynamics in plants. Here we performed a mass spectrometry-based analysis to survey the lipid profiles of Arabidopsis rosettes under various hypoxic conditions. We observed that hypoxia caused a significant increase in total amounts of phosphatidylserine, phosphatidic acid and oxidized lipids, but a decrease in phosphatidylcholine (PC) and phosphatidylethanolamine (PE). Particularly, significant gains in the polyunsaturated species of PC, PE and phosphatidylinositol, and losses in their saturated and mono-unsaturated species were evident during hypoxia. Moreover, hypoxia led to a remarkable elevation of ceramides and hydroxyceramides. Disruption of ceramide synthases LOH1, LOH2 and LOH3 enhanced plant sensitivity to dark submergence, but displayed more resistance to submergence under light than wild type. Consistently, levels of unsaturated very-long-chain (VLC) ceramide species (22:1, 24:1 and 26:1) predominantly declined in the loh1, loh2 and loh3 mutants under dark submergence. In contrast, significant reduction of VLC ceramides in the loh1-1 loh3-1 knockdown double mutant and lacking of VLC unsaturated ceramides in the ads2 mutants impaired plant tolerance to both dark and light submergences. Evidence that C24:1-ceramide interacted with recombinant CTR1 protein and inhibited its kinase activity in vitro, enhanced ER-to-nucleus translocation of EIN2-GFP and stabilization of EIN3-GFP in vivo, suggests a role of ceramides in modulating CTR1-mediated ethylene signaling. The dark submergence-sensitive phenotypes of loh mutants were rescued by a ctr1-1 mutation. Thus, our findings demonstrate that unsaturation of VLC ceramides is a protective strategy for hypoxic tolerance in Arabidopsis.
Collapse
Affiliation(s)
- Li-Juan Xie
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Qin-Fang Chen
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Mo-Xian Chen
- State Key Laboratory of Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Lu-Jun Yu
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Li Huang
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Liang Chen
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Feng-Zhu Wang
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Fan-Nv Xia
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Tian-Ren Zhu
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Jian-Xin Wu
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Jian Yin
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Bin Liao
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Jianxin Shi
- School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Jian-Hua Zhang
- State Key Laboratory of Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Asaph Aharoni
- Department of Plant Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Nan Yao
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Wensheng Shu
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Shi Xiao
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| |
Collapse
|
13
|
Sousa SB, Jenkins D, Chanudet E, Tasseva G, Ishida M, Anderson G, Docker J, Ryten M, Sa J, Saraiva JM, Barnicoat A, Scott R, Calder A, Wattanasirichaigoon D, Chrzanowska K, Simandlová M, Van Maldergem L, Stanier P, Beales PL, Vance JE, Moore GE. Gain-of-function mutations in the phosphatidylserine synthase 1 (PTDSS1) gene cause Lenz-Majewski syndrome. Nat Genet 2014; 46:70-6. [PMID: 24241535 DOI: 10.1038/ng.2829] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Accepted: 10/23/2013] [Indexed: 12/21/2022]
Abstract
Lenz-Majewski syndrome (LMS) is a syndrome of intellectual disability and multiple congenital anomalies that features generalized craniotubular hyperostosis. By using whole-exome sequencing and selecting variants consistent with the predicted dominant de novo etiology of LMS, we identified causative heterozygous missense mutations in PTDSS1, which encodes phosphatidylserine synthase 1 (PSS1). PSS1 is one of two enzymes involved in the production of phosphatidylserine. Phosphatidylserine synthesis was increased in intact fibroblasts from affected individuals, and end-product inhibition of PSS1 by phosphatidylserine was markedly reduced. Therefore, these mutations cause a gain-of-function effect associated with regulatory dysfunction of PSS1. We have identified LMS as the first human disease, to our knowledge, caused by disrupted phosphatidylserine metabolism. Our results point to an unexplored link between phosphatidylserine synthesis and bone metabolism.
Collapse
Affiliation(s)
- Sérgio B Sousa
- 1] Clinical and Molecular Genetics Unit, University College London (UCL) Institute of Child Health, London, UK. [2] Serviço de Genética Médica, Hospital Pediátrico, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal
| | - Dagan Jenkins
- 1] Molecular Medicine Unit, UCL Institute of Child Health, London, UK. [2]
| | - Estelle Chanudet
- 1] Centre for Translational Genomics-GOSgene, UCL Institute of Child Health, London, UK. [2]
| | - Guergana Tasseva
- 1] Group on the Molecular and Cell Biology of Lipids, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada. [2]
| | - Miho Ishida
- Clinical and Molecular Genetics Unit, University College London (UCL) Institute of Child Health, London, UK
| | - Glenn Anderson
- Histopathology Department, Great Ormond Street Hospital for Children, London, UK
| | - James Docker
- Neural Development Unit, UCL Institute of Child Health, London, UK
| | - Mina Ryten
- 1] Reta Lila Weston Institute, UCL Institute of Neurology, London, UK. [2] Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
| | - Joaquim Sa
- Serviço de Genética Médica, Hospital Pediátrico, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal
| | - Jorge M Saraiva
- 1] Serviço de Genética Médica, Hospital Pediátrico, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal. [2] University Clinic of Pediatrics, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Angela Barnicoat
- Clinical Genetics Department, Great Ormond Street Hospital, London, UK
| | - Richard Scott
- Clinical Genetics Department, Great Ormond Street Hospital, London, UK
| | - Alistair Calder
- Radiology Department, Great Ormond Street Hospital, London, UK
| | | | - Krystyna Chrzanowska
- Department of Medical Genetics, Children's Memorial Health Institute, Warsaw, Poland
| | - Martina Simandlová
- Department of Biology and Medical Genetics, University Hospital Motol and Second Faculty of Medicine, Prague, Czech Republic
| | - Lionel Van Maldergem
- 1] Centre de Génétique Humaine, Université de Franche-Comté, Besançon, France. [2] Cutis Laxa Study Group, University of Franche-Comté, Besancon, France
| | - Philip Stanier
- Neural Development Unit, UCL Institute of Child Health, London, UK
| | - Philip L Beales
- 1] Molecular Medicine Unit, UCL Institute of Child Health, London, UK. [2] Centre for Translational Genomics-GOSgene, UCL Institute of Child Health, London, UK
| | - Jean E Vance
- Group on the Molecular and Cell Biology of Lipids, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Gudrun E Moore
- Clinical and Molecular Genetics Unit, University College London (UCL) Institute of Child Health, London, UK
| |
Collapse
|
14
|
Baldridge RD, Xu P, Graham TR. Type IV P-type ATPases distinguish mono- versus diacyl phosphatidylserine using a cytofacial exit gate in the membrane domain. J Biol Chem 2013; 288:19516-27. [PMID: 23709217 PMCID: PMC3707653 DOI: 10.1074/jbc.m113.476911] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Revised: 05/09/2013] [Indexed: 12/22/2022] Open
Abstract
Type IV P-type ATPases (P4-ATPases) use the energy from ATP to "flip" phospholipid across a lipid bilayer, facilitating membrane trafficking events and maintaining the characteristic plasma membrane phospholipid asymmetry. Preferred translocation substrates for the budding yeast P4-ATPases Dnf1 and Dnf2 include lysophosphatidylcholine, lysophosphatidylethanolamine, derivatives of phosphatidylcholine and phosphatidylethanolamine containing a 7-nitro-2-1,3-benzoxadiazol-4-yl (NBD) group on the sn-2 C6 position, and were presumed to include phosphatidylcholine and phosphatidylethanolamine species with two intact acyl chains. We previously identified several mutations in Dnf1 transmembrane (TM) segments 1 through 4 that greatly enhance recognition and transport of NBD phosphatidylserine (NBD-PS). Here we show that most of these Dnf1 mutants cannot flip diacylated PS to the cytosolic leaflet to establish PS asymmetry. However, mutation of a highly conserved asparagine (Asn-550) in TM3 allowed Dnf1 to restore plasma membrane PS asymmetry in a strain deficient for the P4-ATPase Drs2, the primary PS flippase. Moreover, Dnf1 N550 mutants could replace the Drs2 requirement for growth at low temperature. A screen for additional Dnf1 mutants capable of replacing Drs2 function identified substitutions of TM1 and 2 residues, within a region called the exit gate, that permit recognition of dually acylated PS. These TM1, 2, and 3 residues coordinate with the "proline + 4" residue within TM4 to determine substrate preference at the exit gate. Moreover, residues from Atp8a1, a mammalian ortholog of Drs2, in these positions allow PS recognition by Dnf1. These studies indicate that Dnf1 poorly recognizes diacylated phospholipid and define key substitutions enabling recognition of endogenous PS.
Collapse
Affiliation(s)
- Ryan D. Baldridge
- From the Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37235
| | - Peng Xu
- From the Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37235
| | - Todd R. Graham
- From the Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37235
| |
Collapse
|
15
|
Chandrasekaran S, Dayakar A, Veronica J, Sundar S, Maurya R. An in vitro study of apoptotic like death in Leishmania donovani promastigotes by withanolides. Parasitol Int 2013; 62:253-61. [PMID: 23416156 DOI: 10.1016/j.parint.2013.01.007] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Revised: 01/22/2013] [Accepted: 01/28/2013] [Indexed: 11/17/2022]
Abstract
The aim of this study was to isolate and evaluate the withanolides in inducing apoptotic like death in Leishmania donovani in vitro. Withanolides were fractionated and isolated from the leaves of Withania somnifera and LC-MS/MS analysis of two fractions namely, F5 and F6 of ethanolic extracts, obtained through column chromatography with silica gel, was performed. The antileishmanial effect of withanolides on L. donovani promastigotes was assessed in vitro using PI dye exclusion test. The effect of withanolides on promastigote morphology was determined by scanning electron microscopy. To understand their mode of action against L. donovani, DNA fragmentation, quantification of parasites at sub G0/G1 phase, determination of phosphatidylserine externalization, measurement of reactive oxygen species (ROS) and mitochondrial membrane potential (Ψm) were done. Results showed that LC-MS/MS analysis confirmed the presence of withanolides in isolated fractions. Treatment with withanolides resulted in morphological alterations from spindle to round shape and loss of flagella/cell integrity in promastigotes. Moreover, it induced DNA nicks, cell cycle arrest at sub G0/G1 phase and externalization of phosphatidylserine in dose and time dependent manner via increase in ROS and decrease in Ψm. Results of this study indicate that withanolides induce apoptotic like death through the production of ROS from mitochondria and disruption of Ψm in promastigotes of L donovani.
Collapse
Affiliation(s)
- Sambamurthy Chandrasekaran
- Department of Animal Sciences, University of Hyderabad, Prof. C.R. Rao Road, Gachibowli, Hyderabad, AP, India
| | | | | | | | | |
Collapse
|
16
|
Fujita H, Sakuma R, Tomiyama J, Hamaki T, Ohwada A, Nishimura S. Relationship between clotting activity and phosphatidylserine expression on erythrocyte membranes in polycythemia vera patients with the JAK2 V617F mutation. Arch Physiol Biochem 2011; 117:231-5. [PMID: 21539404 DOI: 10.3109/13813455.2011.571262] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
INTRODUCTION Polycythemia vera (PV) accompanies the clinical course of thrombosis. Phosphatidylserine (PS) expression on the plasma membrane has been known to be one of place where the coagulation system activates. We studied the relationship between clotting factor activity and PS expression on the erythrocyte membrane in patients with erythrocytosis. METHODS The coagulation test and PS expression in 23 patients with erythrocytosis were measured. PS expression was determined indirectly by measuring annexin V binding to erythrocytes using fluorescence activated cell sorter analysis (FACS). RESULTS The activity of clotting factors (II, V, VII, VIII, von Willebrand factor, IX, X) was significantly lower in PV than in the mutation-negative erythrocytosis. There was a significant correlation between reduced activity of clotting factors such as V, X, and IX and increased PS expression of the erythrocyte membrane. CONCLUSION Increased expression of PS on the erythrocyte membrane may reduce the activities of clotting factors in PV patients with JAK2 V617F mutation.
Collapse
Affiliation(s)
- Hiroshi Fujita
- Department of Transfusion Medicine, Tokyo Metropolitan Bokutoh Hospital, 4-23-15 Koutoubashi, Sumida-ku, Tokyo 130-8575, Tokyo, Japan.
| | | | | | | | | | | |
Collapse
|
17
|
Cornforth AN, Fowler AW, Carbonell DJ, Dillman RO. Resistance to the proapoptotic effects of interferon-gamma on melanoma cells used in patient-specific dendritic cell immunotherapy is associated with improved overall survival. Cancer Immunol Immunother 2011; 60:123-31. [PMID: 20960187 PMCID: PMC11029524 DOI: 10.1007/s00262-010-0925-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Accepted: 10/05/2010] [Indexed: 12/22/2022]
Abstract
The use of whole cell tumor vaccines and various means of loading antigen onto dendritic cells have been under investigation for over a decade. Induction of apoptosis and the exposure of immune-stimulating proteins are thought to be beneficial for the use in immunotherapy protocols, but conclusive evidence in the clinical setting has been lacking. Incubation of melanoma cell lines with interferon-gamma (IFN-γ) increased phosphatidylserine and calreticulin exposure, but not in the IFN-γ-resistant cell line Lu-1205. Short-term autologous melanoma cell lines used for loading dendritic cells for immunotherapy showed differential response to the pro-apoptotic effects of IFN-γ. These IFN-γ-treated tumor cells (TCs) were irradiated and used for loading antigen for dendritic cell therapy. A log-rank comparison of survival for patients whose TCs were found to be either sensitive (upregulated phosphatidylserine and calreticulin) or insensitive to IFN-γ revealed a strongly significant correlation to progression-free (p = 0.003) and overall survival (p = 0.002) favorably in those patients whose cell lines were resistant to the proapoptotic effect of IFN-γ. These results suggest that the use of IFN-γ in anti-melanoma dendritic cell-based immunotherapy may only be beneficial when the cells do not undergo apoptosis in response to IFN-γ and support the contention that the use of some apoptotic cells in vaccines may be detrimental.
Collapse
Affiliation(s)
- A N Cornforth
- Cell Biology Laboratory, Hoag Cancer Center, 1 Hoag Drive Bldg 41, 92663, Newport Beach, CA, USA.
| | | | | | | |
Collapse
|
18
|
Guchhait P, Dasgupta SK, Le A, Yellapragada S, López JA, Thiagarajan P. Lactadherin mediates sickle cell adhesion to vascular endothelial cells in flowing blood. Haematologica 2008; 92:1266-7. [PMID: 17768123 DOI: 10.3324/haematol.11379] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Increased exposure of sickle red blood cells to phosphatidylserine promotes its adhesion to the endothelium. A monoclonal antibody to lactadherin, a phosphatidylserine binding protein, inhibits sickle cell adhesion to histamine-stimulated endothelial cells in flowing blood. Added lactadherin enhances the adhesion via the integrin alphaVbeta3. These results indicate that lactadherin can mediate phosphatidylserine-expressing sickle cell adhesion to the endothelium.
Collapse
|
19
|
Dasgupta SK, Thiagarajan P. The role of lactadherin in the phagocytosis of phosphatidylserine-expressing sickle red blood cells by macrophages. Haematologica 2005; 90:1267-8. [PMID: 16154850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/04/2023] Open
Abstract
Lactadherin is a phosphatidylserine-binding glycoprotein secreted by macrophages. Less than 0.5% of normal circulating red cells showed any binding to lactadherin. However, the red cells from patients with sickle cell disease showed 2 to 10-fold increases in lactadherin binding. Further, lactadherin stimulated the phagocytosis of sickle red blood cells by macrophages suggesting a potential role in sickle red cell clearance.
Collapse
|
20
|
Abstract
Inter- and intramembrane phospholipid transport processes are central features of membrane biogenesis and homeostasis. Relatively recent successes in the molecular genetic analysis of aminoglycerophospholipid transport processes in both yeast and mammalian cells are now providing important new information defining specific protein and lipid components that participate in these reactions. Studies focused on phosphatidylserine (PtdSer) transport to the mitochondria reveal that the process is regulated by ubiquitination. In addition, a specific mutation disrupts PtdSer transport between mitochondrial membranes. Analysis of PtdSer transport from the endoplasmic reticulum to the locus of PtdSer decarboxylase 2 demonstrates the requirement for a phosphatidylinositol-4-kinase, a phosphatidylinositol-binding protein, and the C2 domain of the decarboxylase. Examination of NBD-phosphatidylcholine transport demonstrates the involvement of the prevacuolar compartment and a requirement for multiple genes involved in regulating vacuolar protein sorting for transport of the lipid to the vacuole. In intramembrane transport, multiple genes are now identified including those encoding multidrug resistant protein family members, DNF family members, ATP binding cassette transporters, and pleiotropic drug resistance family members. The scramblase family constitutes a collection of putative transmembrane transporters that function in an ATP-independent manner. The genetic analysis of lipid traffic is uncovering new molecules involved in all aspects of the regulation and execution of the transport steps and also providing essential tools to critically test the involvement of numerous candidate molecules.Key words: lipid transport, lipid sorting, membrane biogenesis, organelles, flippase.
Collapse
Affiliation(s)
- Dennis R Voelker
- Department of Medicine, National Jewish Medical and Research Center, Denver, CO 80206, USA.
| |
Collapse
|
21
|
Abstract
In mammalian cells, phosphatidylserine (PtdSer) is synthesized through the action of the endoplasmic reticulum enzymes, PtdSer synthase 1 and 2, and the decarboxylation of PtdSer accounts for the majority of phosphatidylethanolamine (PtdEtn) synthesis. PtdSer decarboxylation for PtdEtn formation occurs in the mitochondria. In addition, the transport of PtdSer from the endoplasmic reticulum to the mitochondria is probably a rate limiting step for PtdEtn synthesis through the decarboxylation pathway. Therefore, the regulation of PtdSer synthesis and its intracellular transport appear to be essential events for the maintenance of normal cellular PtdSer and PtdEtn levels. Here we describe the current understanding of the regulation of PtdSer biosynthesis and the transport of PtdSer from the ER to the mitochondria in mammalian cells.
Collapse
Affiliation(s)
- Osamu Kuge
- Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, Toyama 1-23-1, Shinjuku-ku, Tokyo 162-8640.
| | | |
Collapse
|
22
|
Haga JH, Slack SM, Jennings LK. Comparison of shear stress-induced platelet microparticle formation and phosphatidylserine expression in presence of alphaIIbbeta3 antagonists. J Cardiovasc Pharmacol 2003; 41:363-71. [PMID: 12605014 DOI: 10.1097/00005344-200303000-00004] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The use of platelet glycoprotein IIb-IIIa (alphaIIbbeta3) antagonists is an accepted practice in the treatment of acute coronary syndromes. Recent studies have demonstrated that alpha beta receptor antagonists are effective in inhibiting the procoagulant activity of platelets under static conditions. No investigation, however, has compared the ability of these platelet antagonists to inhibit platelet procoagulant activity, defined as an increase in phosphatidylserine (PS) expression, under conditions of shear stress. Thus, the goal of this study was to quantify the amount of microparticle formation and PS expression of platelets exposed to physiologic and pathophysiologic levels of shear stress in the absence and presence of three clinically approved parenteral alpha beta antagonists (abciximab, eptifibatide, and tirofiban). Flow cytometric results demonstrated that although microparticle formation was significantly inhibited by all three antagonists, PS expression by sheared platelets was affected differently depending on the antagonist present. Specifically, abciximab suppressed PS expression compared with the saline control; both abciximab and eptifibatide significantly reduced PS expression compared with tirofiban; and tirofiban potentiated PS expression relative to the saline control at the highest shear stress. This is the first demonstration of differential regulation of platelet PS expression and, by inference, procoagulant activity in the presence of alpha receptor antagonists under shear stress. The current results may have future importance in improving the design of platelet antagonists as well as defining the general role of fluid shear stress in platelet thrombus formation.
Collapse
Affiliation(s)
- Jason H Haga
- Whitaker Institute of Biomedical Engineering, University of California, San Diego, La Jolla, California, USA
| | | | | |
Collapse
|
23
|
Cherepnev GV, Kern F, Garaev RS. [Xymedon decreases phosphatidylserine membrane expression induced by proapoptogenic deficit of serum growth factors in Jurkat T-cells]. Eksp Klin Farmakol 2002; 65:40-3. [PMID: 12227095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
Abstract
The effect of xymedone, a non-glucoside analog of pyridine nucleosides, on the apoptosis of human CD4+ T cells of the Jurkat line was studied by laser flow cytometry method. Xymedone decreased the membrane expression of phosphatidylserine and suppressed the increase in permeability of the cytoplasmic membrane, thus inhibiting the onset of a degradation stage of the apoptotic cascade. Possible mechanisms of the antiapoptogenic effect of xymedone within the framework of a (cytochrome C/caspase 3)-dependent signal pathway of the apoptosis are discussed.
Collapse
Affiliation(s)
- G V Cherepnev
- Clinical Flow Cytometry Laboratory, Republic Medical Diagnostic Center, ul. Chekhova la, Kazan, Tatarstan, Russia
| | | | | |
Collapse
|
24
|
Conesa-Zamora P, Lopez-Andreo MJ, Gómez-Fernández JC, Corbalán-García S. Identification of the phosphatidylserine binding site in the C2 domain that is important for PKC alpha activation and in vivo cell localization. Biochemistry 2001; 40:13898-905. [PMID: 11705379 DOI: 10.1021/bi011303o] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The C2 domain of classical PKCs binds to membranes through Ca(2+) bridging to phosphatidylserine as recently observed through X-ray diffraction of the isolated domain. Additionally, it has been proposed that N189, T251, R216, and R249A interact directly with phosphatidylserine [Verdaguer, N., et al. (1999) EMBO J. 18, 6329-6338]. When these four residues were mutated to Ala to determine their role in PKC binding to phospholipid membranes, PKC activation, and in its in vivo localization, the results revealed that they were very important for the activation of full-length PKCalpha. N189, in particular, was involved in the activation of the enzyme after its interaction with PS, since its mutation to Ala did not decrease the level of membrane binding but did prevent full enzyme activation. On the other hand, mutations R216A, R249A, and T251A affected both membrane binding and enzyme activation, although T251A had the most drastic effect, suggesting that the protein interactions with the carbonyl groups of the phospholipid are also a key event in the activation process. Taken together, these results show that the four residues located near the calcium binding site are critical in phosphatidylserine-dependent PKCalpha activation, in which N189 plays an important role, triggering the enzyme activation probably by interacting with neighboring residues of the protein when lipid binding occurs. Furthermore, these results provide strong evidence for better defining one of the two phosphatidylserine isomer models proposed in the previous crystallographic report.
Collapse
Affiliation(s)
- P Conesa-Zamora
- Departamento de Bioquímica y Biología Molecular (A), Facultad de Veterinaria, Universidad de Murcia, Apartado de Correos 4021, E-30100 Murcia, Spain
| | | | | | | |
Collapse
|
25
|
Abstract
Activation of the metabotropic glutamate receptor (mGluR) system can prevent free radical, nitric oxide (NO)-induced programmed cell death (PCD). To investigate the mechanisms utilized by the mGluR system to regulate the induction of PCD, we examined the course of PCD in real time in individual, living, primary hippocampal neurons. We assessed both phosphatidylserine (PS) externalization, an early event in PCD, and DNA fragmentation during NO toxicity and mGluR modulation to determine the individual contributions of PS externalization and genomic DNA fragmentation during neuronal PCD. Exposure to the NO donors (300 microM SNP or 300 microM NOC-9) induced PCD in approximately 75% of neurons over a 24-h period. The externalization of PS in neurons increased to 21 +/- 2% as early as 3 h following NO exposure and then increased to 80 +/- 2% over a 24-h period. The externalization of PS was independent of the loss of membrane integrity. Agonists for individual mGluR subgroups were equally able to prevent NO-induced neuronal death and DNA degradation, yet they possessed differential abilities to regulate PS externalization. The group I agonist DHPG (750 microM) and the group III agonist L-AP4 (750 microM) both prevented and reversed NO-induced PS externalization. In contrast, activation of group II subtypes using L-CCG-I (750 microM) did not prevent PS externalization. Employing an experimental model that independently led to the externalization of PS residues, we demonstrated that PS externalization does not immediately impact on neuronal survival. Yet, subsequent neuronal survival may ultimately depend upon preventing PS externalization to avoid neuronal tagging for phagocytosis. Since group I and III mGluR subtypes possess the unique ability to maintain genomic integrity and membrane PS asymmetry, these agents may provide superior overall protection against NO-induced neuronal injury.
Collapse
Affiliation(s)
- A M Vincent
- Laboratory of Cellular and Molecular Cerebral Ischemia, Wayne State University School of Medicine, Detroit, Michigan 48201, USA
| | | |
Collapse
|
26
|
Abstract
The aminoglycerophospholipids of eukaryotic cells, phosphatidylserine (PtdSer), phosphatidylethanolamine (PtdEtn), and phosphatidylcholine (PtdCho), can be synthesized by multiple pathways. The PtdSer pathway encompasses the synthesis of PtdSer, its decarboxylation to PtdEtn and subsequent methylation reactions to form PtdCho. The Kennedy pathways consist of the synthesis of PtdEtn and PtdCho from Etn and Cho precursors via CDP-Etn and CDP-Cho intermediates. The reactions along the PtdSer pathway are spatially segregated with PtdSer synthesis occurring in the endoplasmic reticulum or mitochondria-associated membrane (MAM), PtdEtn formation occurring in the mitochondria and Golgi/vacuole compartments and PtdCho formation occurring in the endoplasmic reticulum or MAM. The organelle-specific metabolism of the different lipids in the PtdSer pathway has provided a convenient biochemical means for defining events in the interorganelle transport of the aminoglycerophospholipids in intact cells, isolated organelles and permeabilized cells. Studies with both mammalian cells and yeast demonstrate many significant similarities in lipid transport processes between the two systems. Genetic experiments in yeast now provide the tools to create new strains with mutations along the PtdSer pathway that can be conditionally rescued by the Kennedy pathway reactions. The genetic studies in yeast indicate that it is now possible to begin to define genes that participate in the interorganelle transport of the aminoglycerophospholipids.
Collapse
Affiliation(s)
- D R Voelker
- Department of Medicine, National Jewish Medical and Research Center, Denver, CO 80206, USA.
| |
Collapse
|
27
|
Nakamura H, Miura K, Fukuda Y, Shibuya I, Ohta A, Takagi M. Phosphatidylserine synthesis required for the maximal tryptophan transport activity in Saccharomyces cerevisiae. Biosci Biotechnol Biochem 2000; 64:167-72. [PMID: 10705462 DOI: 10.1271/bbb.64.167] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Saccharomyces cerevisiae cho1/pss mutants, which are severely impaired in phosphatidylserine (PS) synthesis, do not have detectable amounts of PS in their lipid fractions. Their derivatives with mutations that cause defects in tryptophan synthesis grew poorly in a medium containing 5 micrograms/ml of L-tryptophan, a concentration that met the requirements of tryptophanauxotrophic CHO1/PSS strains. The rates of tryptophan uptake of trp1 cho1/pss mutants were low at low tryptophan concentrations. This defect in the use of tryptophan was restored either by expression of CHO1/PSS or by introduction of a gene encoding tryptophan transporter, TAT1 or TAT2. These results indicate that PS synthesis is required for the maximal tryptophan-transporting activity of S. cerevisiae at low tryptophan concentrations.
Collapse
Affiliation(s)
- H Nakamura
- Department of Biotechnology, University of Tokyo, Japan
| | | | | | | | | | | |
Collapse
|
28
|
Abstract
A Saccharomyces cerevisiae mutant in cell division cycle gene CDC48 shows typical markers of apoptosis: membrane staining with annexin V, indicating an exposure of phosphatidylserine at the outer layer of the cytoplasmic membrane; intense staining, using the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling method, indicating DNA fragmentation; and chromatin condensation and fragmentation. The coordinate occurrence of these events at different locations in the cell, which have no obvious connection except their relation to apoptosis, implies the presence of the molecular machinery performing the basic steps of apoptosis already in yeast. Saccharomyces cerevisiae may prove a suitable model to trace the roots of apoptosis.
Collapse
Affiliation(s)
- F Madeo
- Physiologisch-chemisches Institut, Universität Tübingen, 72076 Tübingen, Germany
| | | | | |
Collapse
|
29
|
Abstract
The endogenous phosphatidylserine of normal erythrocytes is confined to the cytoplasmic leaflet of the membrane. However, under pathologic conditions transmembrane asymmetry can be altered and cytofacial phosphatidylserine may appear on the cell surface. A sensitive alternative method for the measurement of the exposed phosphatidylserine content of erythrocyte membrane was developed using the activation of exogenous protein kinase C. Erythrocytes containing exogenous phosphatidylcholine incorporated into the outer membrane monolayer do not stimulate protein kinase C activity more than untreated cells. In contrast, red cells that have exogenous phosphatidylserine incorporated into their membrane outer monolayer, by prior inhibition of the aminophospholipid transporter, stimulate protein kinase C significantly more than red cells in which exogenous phosphatidylserine is allowed to translocate to the inner membrane monolayer. Kinase activation is comparable for normal cells and cells not exposed to lipid in which the aminophospholipid transporter is inhibited with sulfhydryl reagents (diamide or N-ethylmaleimide). However, Ca(2+)-loading results in an increase in activation of protein kinase C over control cells, consistent with previous reports that Ca2+ induces the exposure of erythrocyte and platelet phosphatidylserine. By reference to protein kinase C activation by phosphatidylserine in model systems, the quantity of phosphatidylserine on the cell surface may be estimated. Thus, protein kinase C activation affords a sensitive and specific measure of phosphatidylserine in the outer monolayer of biological membranes.
Collapse
Affiliation(s)
- D L Daleke
- Department of Chemistry, Indiana University, Bloomington 47405
| | | | | |
Collapse
|
30
|
Ortel TL, Devore-Carter D, Quinn-Allen M, Kane WH. Deletion analysis of recombinant human factor V. Evidence for a phosphatidylserine binding site in the second C-type domain. J Biol Chem 1992; 267:4189-98. [PMID: 1740460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Human coagulation factor V is an integral component of the prothrombinase complex. Rapid activation of prothrombin is dependent on the interactions of this nonenzymatic cofactor with factor Xa and prothrombin in the presence of calcium ions and a phospholipid or platelet surface. Factor V is similar structurally and functionally to the homologous cofactor, factor VIII, which interacts with factor IXa to accelerate factor X activation in the presence of calcium and phospholipids. Both of these cofactors, when activated, possess homologous heavy and light chains. Binding to anionic phospholipids is mediated by the light chains of these two cofactors. In bovine factor Va, a phosphatidylserine-specific binding site has been localized to the amino-terminal A3 domain of the light chain. In human factor VIII, on the other hand, a region within the carboxyl-terminal C2 domain of the light chain has been shown to interact with anionic phospholipids. We have constructed a series of recombinant deletion mutants lacking domain-size fragments of the light chain of human factor V (rHFV). These mutants are expressed and secreted as single-chain proteins by COS cells. Thrombin and the factor V activator from Russell's viper venom process these deletion mutants as expected. The light chain deletion mutants possess essentially no procoagulant activity, nor are they activated by treatment with factor V activator from Russell's viper venom. Deletion of the second C-type domain results in essentially complete loss of phosphatidylserine-specific binding whereas the presence of the C2 domain alone (rHFV des-A3C1, which lacks the A3 and C1 domains of the light chain) results in significant phosphatidylserine-specific binding. The presence of the A3 domain alone (rHFV des-C1C2) does not mediate binding to immobilized phosphatidylserine. Increasing calcium ion concentrations result in decreased binding of recombinant human factor V and the mutant rHFV des-A3C1 to phosphatidylserine, similar to previous studies with purified plasma factor V and phospholipid vesicles. These results indicate that human factor V, similar to human factor VIII, possesses a phosphatidylserine-specific binding site within the C2 domain of the light chain.
Collapse
Affiliation(s)
- T L Ortel
- Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710
| | | | | | | |
Collapse
|
31
|
Gupta SD, Dowhan W, Wu HC. Phosphatidylethanolamine is not essential for the N-acylation of apolipoprotein in Escherichia coli. J Biol Chem 1991; 266:9983-6. [PMID: 2033085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
It has been postulated that the N-acyl fatty acid attached to the amino terminus of the major Escherichia coli lipoprotein is derived from the fatty acid at the 1-position of phosphatidylethanolamine (PtdEtn) (Jackowski, S., and Rock, C.O. (1986) J. Biol. Chem. 261, 11328-11333). To ascertain the role of PtdEtn in the conversion of apolipoprotein to the mature lipoprotein, the lipoprotein from E. coli strain AH930 (pss::kan) containing a null mutation in the phosphatidylserine synthase gene (pss) was studied. Pulse labeling with [35S]methionine for 30 s or 5 min revealed the formation of mature lipoprotein in both wild-type (W3110) and mutant (AH930) cells. [3H]Palmitate-labeled lipoproteins from both the mutant and wild-type cells were found to contain nearly identical amounts of alkali-resistant (amide-linked, 41-42%) and alkali-labile (ester-linked, 58-59%) fatty acids. Edman degradation and dansylation of the immuno-affinity-purified [35S]cysteine-labeled lipoprotein showed that the NH2 terminus of the lipoprotein in the mutant was blocked as in the wild type. In vitro assay of apolipoprotein N-acyltransferase using membranes either from the mutant or the wild-type strain as the source of both the enzyme and the acyl donor revealed that both membranes were equally active in the conversion of [35S]methionine-labeled apolipoprotein to lipoprotein. These data strongly suggest that PtdEtn is not essential for the N-acylation of apolipoprotein to form lipoprotein, and other major phospholipids such as phosphatidylglycerol and cardiolipin can serve as the donor of fatty acid in the N-acylation of apolipoprotein.
Collapse
Affiliation(s)
- S D Gupta
- Department of Microbiology, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814-4799
| | | | | |
Collapse
|
32
|
Kuge O, Nishijima M, Akamatsu Y. A cloned gene encoding phosphatidylserine decarboxylase complements the phosphatidylserine biosynthetic defect of a Chinese hamster ovary cell mutant. J Biol Chem 1991; 266:6370-6. [PMID: 2007589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
A phosphatidylserine-auxotrophic mutant of cultured Chinese hamster ovary cells, PSA-3, manifests a defect in phosphatidylserine synthase I activity (Kuge, O., Nishijima, M., and Akamatsu, Y. (1986) J. Biol. Chem. 261, 5790-5794). We cloned a Chinese hamster gene, designated pssC, which was able to transform the PSA-3 cell line to a phosphatidylserine prototroph. The resultant transformant contained phosphatidylserine in normal amounts but remained defective in phosphatidylserine synthase I activity, indicating that pssC is a suppressor gene. Using the genomic fragment of pssC as a probe, a cDNA clone of pssC was isolated, and its nucleotide sequence was determined. A computer search through a protein data bank revealed that pssC had homology with the Escherichia coli psd gene encoding the proenzyme of phosphatidylserine decarboxylase at the amino acid level. Introduction of the cloned pssC gene into PSA-3 resulted in a 2-fold increase in phosphatidylserine decarboxylase activity. When the pssC cDNA was placed downstream of the yeast GAL1 promoter and introduced into yeast Saccharomyces cerevisiae cells, the phosphatidylserine decarboxylase activity increased in a galactose-dependent manner. These results indicate that pssC encodes phosphatidylserine decarboxylase. The mechanism by which pssC complements the defect of PSA-3 in phosphatidylserine biosynthesis is discussed.
Collapse
Affiliation(s)
- O Kuge
- Department of Chemistry, National Institute of Health, Tokyo, Japan
| | | | | |
Collapse
|
33
|
Abstract
Three mutants of the yeast Saccharomyces cerevisiae which require exogenous ethanolamine or choline were isolated. The mutants map to a single locus (cho1) on chromosome V. The lipid composition suggests that cho1 mutants do not synthesize phosphatidylserine under any growth conditions. If phosphatidylethanolamine or phosphatidylcholine, which are usually derived from phosphatidylserine, were synthesized from exogenous ethanolamine or choline, the mutants grew and divided relatively normally. However, mitochondrial abnormalities were evident even when ethanolamine and choline were supplied. Diploids homozygous for the cho1 mutation were defective in sporulation. Growth on nonfermentable carbon sources was slow, and a high proportion of respiratory-deficient (petite) cells were generated in cho1 cultures.
Collapse
|