1
|
Mapping trasmembrane distribution of sphingomyelin. Emerg Top Life Sci 2023; 7:31-45. [PMID: 36692108 DOI: 10.1042/etls20220086] [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: 10/31/2022] [Revised: 12/23/2022] [Accepted: 01/10/2023] [Indexed: 01/25/2023]
Abstract
Our knowledge on the asymmetric distribution of sphingomyelin (SM) in the plasma membrane is largely based on the biochemical analysis of erythrocytes using sphingomyelinase (SMase). However, recent studies showed that the product of SMase, ceramide, disturbs transmembrane lipid distribution. This led to the development of the complimentary histochemical method, which combines electron microscopy and SM-binding proteins. This review discusses the advantages and caveats of published methods of measuring transbilayer distribution of SM. Recent finding of the proteins involved in the transbilayer movement of SM will also be summarized.
Collapse
|
2
|
Influence of Antiplatelet Agents on the Lipid Composition of Platelet Plasma Membrane: A Lipidomics Approach with Ticagrelor and Its Active Metabolite. Int J Mol Sci 2021; 22:ijms22031432. [PMID: 33572690 PMCID: PMC7866994 DOI: 10.3390/ijms22031432] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Revised: 01/21/2021] [Accepted: 01/23/2021] [Indexed: 12/18/2022] Open
Abstract
Lipids contained in the plasma membrane of platelets play an important role in platelet function. Modifications in the lipid composition can fluidify or rigidify the environment around embedded receptors, in order to facilitate the access of the receptor by the drug. However, data concerning the lipid composition of platelet plasma membrane need to be updated. In addition, data on the impact of drugs on plasma membrane composition, in particular antiplatelet agents, remain sparse. After isolation of platelet plasma membrane, we assessed, using lipidomics, the effect of ticagrelor, a P2Y12 antagonist, and its active metabolite on the lipid composition of these plasma membranes. We describe the exact lipid composition of plasma membrane, including all sub-species. Ticagrelor and its active metabolite significantly increased cholesterol and phosphatidylcholine ether with short saturated acyl chains 16:0/16:0, and decreased phosphatidylcholine, suggesting overall rigidification of the membrane. Furthermore, ticagrelor and its active metabolite decreased some arachidonylated plasmalogens, suggesting a decrease in availability of arachidonic acid from the membrane phospholipids for synthesis of biologically active mediators. To conclude, ticagrelor and its active metabolite seem to influence the lipid environment of receptors embedded in the lipid bilayer and modify the behavior of the plasma membrane.
Collapse
|
3
|
Léger JL, Pichaud N, Boudreau LH. Purification of Functional Platelet Mitochondria Using a Discontinuous Percoll Gradient. Methods Mol Biol 2021; 2276:57-66. [PMID: 34060032 DOI: 10.1007/978-1-0716-1266-8_4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The isolation of mitochondria is gaining importance in experimental and clinical laboratory settings. Of interest, mitochondria and mitochondrial components (i.e., circular mitochondrial DNA, N-formylated peptides, cardiolipin) have been involved in several human inflammatory pathologies, such as cancer, Alzheimer's disease, Parkinson's disease, and rheumatoid arthritis. While several mitochondrial isolation methods have been previously published, these techniques are aimed at yielding mitochondria from cell types other than platelets. In addition, little information is known on the number of platelet-derived microvesicles that can contaminate the mitochondrial preparation or even the overall quality as well as functional and structural integrity of mitochondria. Here we describe a purification method, using a discontinuous Percoll gradient, yielding mitochondria of high purity and integrity from human platelets.
Collapse
Affiliation(s)
- Jacob L Léger
- Department of Chemistry and Biochemistry, Universite de Moncton, Moncton, NB, Canada
| | - Nicolas Pichaud
- Department of Chemistry and Biochemistry, Universite de Moncton, Moncton, NB, Canada
| | - Luc H Boudreau
- Department of Chemistry and Biochemistry, Universite de Moncton, Moncton, NB, Canada.
| |
Collapse
|
4
|
Carosi JM, Hattersley KJ, Cui Y, Yang Z, Teasdale RD, Sargeant TJ. Subcellular Fractionation of Hela Cells for Lysosome Enrichment Using a Continuous Percoll-Density Gradient. Bio Protoc 2019; 9:e3362. [PMID: 33654860 DOI: 10.21769/bioprotoc.3362] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2019] [Revised: 08/24/2019] [Accepted: 08/15/2019] [Indexed: 11/02/2022] Open
Abstract
The enrichment of lysosomes is a useful way to study their structure and function. These dynamic vesicles can be enriched from cell cultures in a variety of ways including immunoprecipitation and fluorescence-activated organelle sorting. These methods are extremely precise but often require the transfection and expression of an affinity or fluorophore-tagged lysosomal membrane protein. A simpler approach uses differential density of subcellular organelles, which are characteristic to a particular type of organelle. Separation of organelles along a density-gradient enables fractionation to enrich for specific organelles (such as lysosomes) in their native state. This protocol outlines an optimized method for enriching lysosomes from HeLa cells with a continuous density-gradient that contains Percoll. Gentle cell lysis and extraction conditions yield dense-fractions that are enriched with functional and intact lysosomes, which can be assayed in downstream analyses. This method is quick (conducted in less than 2 h after harvesting cells), and can be easily scaled and optimized for other cell types.
Collapse
Affiliation(s)
- Julian M Carosi
- Lysosomal Health in Ageing, Hopwood Centre for Neurobiology, South Australian Health & Medical Research Institute, Adelaide, Australia.,Centre for Cancer Biology, University of South Australia, Adelaide, Australia
| | - Kathryn J Hattersley
- Lysosomal Health in Ageing, Hopwood Centre for Neurobiology, South Australian Health & Medical Research Institute, Adelaide, Australia
| | - Yi Cui
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, Brisbane, Queensland, Australia
| | - Zhe Yang
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, Brisbane, Queensland, Australia
| | - Rohan D Teasdale
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, Brisbane, Queensland, Australia
| | - Timothy J Sargeant
- Lysosomal Health in Ageing, Hopwood Centre for Neurobiology, South Australian Health & Medical Research Institute, Adelaide, Australia
| |
Collapse
|
5
|
Cerecedo D, Martínez-Vieyra I, Sosa-Peinado A, Cornejo-Garrido J, Ordaz-Pichardo C, Benítez-Cardoza C. Alterations in plasma membrane promote overexpression and increase of sodium influx through epithelial sodium channel in hypertensive platelets. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:1891-903. [PMID: 27137675 DOI: 10.1016/j.bbamem.2016.04.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 03/31/2016] [Accepted: 04/27/2016] [Indexed: 12/30/2022]
Abstract
Platelets are small, anucleated cell fragments that activate in response to a wide variety of stimuli, triggering a complex series of intracellular pathways leading to a hemostatic thrombus formation at vascular injury sites. However, in essential hypertension, platelet activation contributes to causing myocardial infarction and ischemic stroke. Reported abnormalities in platelet functions, such as platelet hyperactivity and hyperaggregability to several agonists, contribute to the pathogenesis and complications of thrombotic events associated with hypertension. Platelet membrane lipid composition and fluidity are determining for protein site accessibility, structural arrangement of platelet surface, and response to appropriate stimuli. The present study aimed to demonstrate whether structural and biochemical abnormalities in lipid membrane composition and fluidity characteristic of platelets from hypertensive patients influence the expression of the Epithelial Sodium Channel (ENaC), fundamental for sodium influx during collagen activation. Wb, cytometry and quantitative Reverse Transcription-Polymerase Chain Reaction (qRT-PCR) assays demonstrated ENaC overexpression in platelets from hypertensive subjects and in relation to control subjects. Additionally, our results strongly suggest a key role of β-dystroglycan as a scaffold for the organization of ENaC and associated proteins. Understanding of the mechanisms of platelet alterations in hypertension should provide valuable information for the pathophysiology of hypertension.
Collapse
Affiliation(s)
- D Cerecedo
- Laboratorio de Hematobiología, Escuela Nacional de Medicina y Homeopatía (ENMH), Instituto Politécnico Nacional (IPN), México City, México.
| | - Ivette Martínez-Vieyra
- Laboratorio de Hematobiología, Escuela Nacional de Medicina y Homeopatía (ENMH), Instituto Politécnico Nacional (IPN), México City, México
| | - Alejandro Sosa-Peinado
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), P.O. Box 70-159, 04510, D.F., México City, México
| | - Jorge Cornejo-Garrido
- Laboratorio de Biología Celular y Productos Naturales, ENMH, IPN, México City, México
| | | | | |
Collapse
|
6
|
Chap H. Forty five years with membrane phospholipids, phospholipases and lipid mediators: A historical perspective. Biochimie 2016; 125:234-49. [PMID: 27059515 DOI: 10.1016/j.biochi.2016.04.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 04/01/2016] [Indexed: 01/02/2023]
Abstract
Phospholipases play a key role in the metabolism of phospholipids and in cell signaling. They are also a very useful tool to explore phospholipid structure and metabolism as well as membrane organization. They are at the center of this review, covering a period starting in 1971 and focused on a number of subjects in which my colleagues and I have been involved. Those include determination of phospholipid asymmetry in the blood platelet membrane, biosynthesis of lysophosphatidic acid, biochemistry of platelet-activating factor, first attempts to define the role of phosphoinositides in cell signaling, and identification of novel digestive (phospho)lipases such as pancreatic lipase-related protein 2 (PLRP2) or phospholipase B. Besides recalling some of our contributions to those various fields, this review makes an appraisal of the impressive and often unexpected evolution of those various aspects of membrane phospholipids and lipid mediators. It is also the occasion to propose some new working hypotheses.
Collapse
Affiliation(s)
- Hugues Chap
- Centre de Physiopathologie de Toulouse Purpan, Institut National de la Santé et de la Recherche Médicale, U1043, Toulouse F-31300, France; Centre National de la Recherche Scientifique, U5282, Toulouse F-31300, France; Université de Toulouse, Université Paul Sabatier, Toulouse F-31300, France. hugues.chap.@univ-tlse3.fr
| |
Collapse
|
7
|
Murate M, Kobayashi T. Revisiting transbilayer distribution of lipids in the plasma membrane. Chem Phys Lipids 2016; 194:58-71. [DOI: 10.1016/j.chemphyslip.2015.08.009] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 08/14/2015] [Accepted: 08/17/2015] [Indexed: 12/22/2022]
|
8
|
Chen J, Lobachev KS, Grindel BJ, Farach-Carson MC, Hyzy SL, El-Baradie KB, Olivares-Navarrete R, Doroudi M, Boyan BD, Schwartz Z. Chaperone properties of pdia3 participate in rapid membrane actions of 1α,25-dihydroxyvitamin d3. Mol Endocrinol 2013; 27:1065-77. [PMID: 23660595 DOI: 10.1210/me.2012-1277] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Protein disulfide isomerase family A, member 3 (Pdia3) mediates many of the plasma membrane (PM)-associated rapid responses to 1α,25-dihydroxyvitamin D3 (1α,25[OH]2D3). It is not well understood how Pdia3, which is an endoplasmic reticulum (ER) chaperone, functions as a PM receptor for 1α,25(OH)2D3. We mutated 3 amino acids (K214 and R282 in the calreticulin interaction site and C406 in the isomerase catalytic site), which are important for Pdia3's ER chaperone function, and examined their role in responses to 1α,25(OH)2D3. Pdia3 constructs with and without the ER retention signal KDEL were used to investigate the PM requirement for Pdia3. Finally, we determined whether palmitoylation and/or myristoylation were required for Pdia3-mediated responses to 1α,25(OH)2D3. Overexpressing the Pdia3 R282A mutant in MC3T3-E1 cells increased PM phospholipase A2-activating protein, Rous sarcoma oncogene (c-Src), and caveolin-1 but blocked increases in 1α,25(OH)2D3-stimulated protein kinase C (PKC) seen in cells overexpressing wild-type Pdia3 (Pdia3Ovr cells). Cells overexpressing Pdia3 with K214A and C406S mutations had PKC activity comparable to untreated controls, indicating that the native response to 1α,25(OH)2D3 also was blocked. Overexpressing Pdia3[-KDEL] increased PM localization and augmented baseline PKC, but the stimulatory effect of 1α,25(OH)2D3 was comparable to that seen in wild-type cultures. In contrast, 1α,25(OH)2D3 increased prostaglandin E2 in Pdia3[±KDEL] cells. Although neither palmitoylation nor myristoylation was required for PM association of Pdia3, myristoylation was needed for PKC activation. These data indicate that both the chaperone functional domains and the subcellular location of Pdia3 control rapid membrane responses to 1α,25(OH)2D3.
Collapse
Affiliation(s)
- Jiaxuan Chen
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Lhermusier T, Chap H, Payrastre B. Platelet membrane phospholipid asymmetry: from the characterization of a scramblase activity to the identification of an essential protein mutated in Scott syndrome. J Thromb Haemost 2011; 9:1883-91. [PMID: 21958383 DOI: 10.1111/j.1538-7836.2011.04478.x] [Citation(s) in RCA: 120] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Like all eukaryotic cells, platelets maintain plasma membrane phospholipid asymmetry in normal blood circulation via lipid transporters, which control transbilayer movement. Upon platelet activation, the asymmetric orientation of membrane phospholipids is rapidly disrupted, resulting in a calcium-dependent exposure of the anionic phospholipid, phosphatidylserine (PS), at the outer platelet surface. This newly-exposed PS surface is a major component of normal hemostasis because it supports platelet procoagulant function. Binding of blood clotting enzyme complexes to this negatively-charged membrane surface allows a dramatic increase in the rate of conversion of zymogens to active serine proteases, which in turn produce a burst of thrombin leading to the formation of a fibrin clot and further platelet activation. Cells have the capacity to catalyze transbilayer phospholipid exchange via ATP-requiring translocase enzymes (flippases and floppases), which control unidirectional phospholipid transport against a concentration gradient. They also use an energy-independent, calcium-dependent scramblase activity to govern the bidirectional exchange of phospholipids between the two leaflets of the bilayer; this activity is essential for PS exposure during platelet activation. Scramblase activity, biochemically characterized in the 1980s, is deficient in patients with Scott syndrome, a rare inherited bleeding disorder with defective platelet procoagulant activity. Despite considerable efforts, the platelet scramblase protein remained elusive for years but a significant advance has recently been made with the identification of TMEM16F, a membrane protein essential for calcium-dependent PS exposure whose loss of function mutations are found in Scott syndrome. This review recalls historical aspects of platelet membrane asymmetry characterization, summarizes the mechanisms and roles of PS exposure following platelet activation and discusses the recent identification of TMEM16F and its significance in the scrambling process.
Collapse
Affiliation(s)
- T Lhermusier
- Inserm, U1048 and Université Toulouse 3, I2MC, 31432 Toulouse Cedex 04, France
| | | | | |
Collapse
|
10
|
Roelofsen B. Phospholipases as Tools to Study the Localization of Phospholipids in Biological Membranes. A Critical Review. ACTA ACUST UNITED AC 2008. [DOI: 10.3109/15569548209016468] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
|
11
|
Tessier C, Quinn P, Koumanov K, Trugnan G, Rainteau D, Wolf C. Modulation of the phase heterogeneity of aminoglycerophospholipid mixtures by sphingomyelin and monovalent cations: maintenance of the lamellar arrangement in the biological membranes. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2004; 33:513-21. [PMID: 14997357 DOI: 10.1007/s00249-004-0392-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2003] [Revised: 12/10/2003] [Accepted: 01/22/2004] [Indexed: 11/30/2022]
Abstract
The phase behaviour of mixed molecular species of phosphatidylethanolamine, phosphatidylserine and sphingomyelin of biological origin were examined in aqueous co-dispersions using synchrotron X-ray diffraction. The co-dispersions of phospholipids studied were aimed to model the mixing of lipids populating the cytoplasmic and outer leaflets in the resting or "scrambled" activated cell membrane. Mixtures enriched with phosphatidylethanolamine and phosphatidylserine were characterized by a phase separation of non-lamellar phases (cubic and inverted hexagonal) with a lamellar gel phase comprising the most saturated molecular species. Inclusion of sphingomyelin in the mixture resulted in a suppression of the hexagonal-II phase in favour of lamellar phases at temperatures where a proportion of the phospholipid was fluid. The effect was also dependent on the total amount of sphingomyelin in ternary mixtures, and the lamellar phase dominated in mixtures containing more than 30 mol%, irrespective of the relative proportions of phosphatidylserine/sphingomyelin. A transition from gel to liquid-crystal phase was detected by wide-angle scattering during heating scans of ternary mixtures enriched in sphingomyelin and was shown by thermal cycling experiments to be coupled with a hexagonal-II phase to lamellar transition. In such samples there was evidence of a coexistence of non-lamellar phases with a lamellar gel phase. A transition of the gel phase to the fluid state on heating from 35 to 41 degrees C was evidenced by a progressive increase in the lamellar d-spacing. The presence of calcium enhanced the phase separation of a lamellar gel phase from a hexagonal-II phase in mixtures enriched in phosphatidylserine. This effect was counteracted by charge screening with 150 mM NaCl. The effect of sphingomyelin on stabilizing the lamellar phase is discussed in the context of an altered composition in the cytoplasmic/outer leaflets of the plasma membrane resulting from scrambling of the phospholipid distribution. The results suggest that a lamellar structure can be retained by the inward translocation of sphingomyelin in biological membranes. The presence of monovalent cations serves also to stabilize the bilayer in activated cells where a translocation of aminoglycerophospholipids and an influx of calcium occur simultaneously.
Collapse
Affiliation(s)
- Cedric Tessier
- Faculté de Médecine Saint Antoine, Inserm U538, 27 rue Chaligny, 75012 Paris, France
| | | | | | | | | | | |
Collapse
|
12
|
Bodin S, Tronchère H, Payrastre B. Lipid rafts are critical membrane domains in blood platelet activation processes. BIOCHIMICA ET BIOPHYSICA ACTA 2003; 1610:247-57. [PMID: 12648778 DOI: 10.1016/s0005-2736(03)00022-1] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Among the various hematopoi;etic cells, platelets are critical for maintaining the integrity of the vascular system. They must be rapidly activated by sequential and coordinated mechanisms in order to efficiently prevent haemorrhage upon vascular injury. Several signal transduction pathways lead to platelet activation in vitro and in vivo, among them, several are initiated via receptors or co-receptors containing immuno-receptor tyrosine-based activation motifs (ITAM) which trigger downstream signalling like the immune receptors in lymphocytes. However, in contrast to immune cells for which the role of lipid rafts in signalling has largely been described, the involvement of laterally segregated membrane microdomains in platelet activation has been investigated only recently. The results obtained until now strongly suggest that early steps of platelet activation via the collagen receptor GpVI or via FcgammaRIIa occur preferentially in these microdomains where specific proteins efficiently organize key downstream signalling pathways. In addition, lipid rafts also contribute to platelet activation via heterotrimeric G-protein-coupled receptors. They are sites where the phosphoinositide (PI) metabolism is highly active, leading to a local generation of lipid second messengers such as phosphatidylinositol 3,4,5-trisphosphate. Here, evidence is accumulating that cholesterol-enriched membrane microdomains are part of a general process that contributes to the efficiency and the coordination of platelet activation mechanisms. Here we will discuss the biochemical and functional characterizations of human platelet rafts and their potential impact in platelet physiopathology.
Collapse
Affiliation(s)
- Stéphane Bodin
- INSERM U563, Centre de Physiophatologie Toulouse Purpan, Département d'Oncogenèse et signalisation dans les cellules hématopoi;étiques, Hôpital Purpan 31059, Toulouse, France
| | | | | |
Collapse
|
13
|
Abstract
Most biological membranes possess an asymmetric transbilayer distribution of phospholipids. Endogenous enzymes expend energy to maintain the arrangement by promoting the rate of phospholipid translocation, or flip-flop. Researchers have discovered ways to modify this distribution through the use of chemicals. This review presents a critical analysis of the phospholipid asymmetry data in the literature followed by a brief overview of the maintenance and physiological consequences of phospholipid asymmetry, and finishes with a list of chemical ways to alter phospholipid distribution by enhancement of flip-flop.
Collapse
Affiliation(s)
- J Middleton Boon
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556-5670, USA
| | | |
Collapse
|
14
|
Gallet PF, Zachowski A, Julien R, Fellmann P, Devaux PF, Maftah A. Transbilayer movement and distribution of spin-labelled phospholipids in the inner mitochondrial membrane. BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1418:61-70. [PMID: 10209211 DOI: 10.1016/s0005-2736(99)00022-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The transmembrane diffusion and equilibrium distribution of spin-labelled phosphatidylethanolamine (PE*), phosphatidylcholine (PC*) and cardiolipin (CL*) were investigated in purified mitochondrial inner membranes using electron spin resonance spectroscopy. Using the back exchange technique, we found that the outside-inside movement of PE* and PC* in beef-heart inner mitochondrial membranes was rapid (t1/2 in the range 10-15 min at 30 degrees C). The steady-state distributions in non-energised mitoplasts were approximately 30% in the inner leaflet for PC* and 39% for PE*. Within the limits of probe concentration that can possibly be used in these experiments, the initial velocity of the inward movement was not saturable with respect to the amount of analogue added to the membranes, suggesting that the spin-labelled phospholipids diffused passively between the two leaflets of the inner mitochondrial membrane. In energised mitoplasts, PC* behaviour was not affected, PE* diffused approximately two times faster toward the inner monolayer but reached the same plateau. Treatment of energised mitochondria with N-ethylmaleimide did not affect PC* diffusion, while the kinetics of PE* internalisation became identical to that of PC*. Similar results were found when PC* and PE* movements were studied in mitoplasts from beef heart, rat liver or yeast. The spin-labelled cardiolipin, which possesses four long chains, had to be introduced in the mitoplast with some ethanol. After equilibration (t1/2 of the order of 13 min at 30 degrees C), the transmembrane distribution suggested that approximately half of the cardiolipin analogue remained in the outer leaflet. These results do not allow us to determine if a specific protein (or flippase) is involved in the phospholipid transmembrane traffic within inner mitochondrial membranes, but they show that lipids can rapidly flip through the mitochondrial membrane.
Collapse
Affiliation(s)
- P F Gallet
- Institut de Biotechnologie, Faculté des Sciences, 123 avenue A. Thomas, 87060, Limoges cedex, France
| | | | | | | | | | | |
Collapse
|
15
|
Grange E, Rabin O, Bell J, Chang MC. Manoalide, a phospholipase A2 inhibitor, inhibits arachidonate incorporation and turnover in brain phospholipids of the awake rat. Neurochem Res 1998; 23:1251-7. [PMID: 9804280 DOI: 10.1023/a:1020788031720] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The Fatty Acid method was used to determine whether incorporation of plasma radiolabeled arachidonic acid into brain phospholipids is controlled by phospholipase A2. Awake rats received an i.v. injection of a phospholipase A2 inhibitor, manoalide (10 mg/kg), and then were infused i.v. with [1-(14)C]arachidonate or [3H]arachidonate. Animals were killed after infusion by microwave irradiation, and tracer distribution was analyzed in brain phospholipid, neutral lipid and acyl-CoA pools. Calcium-independent phospholipase A2 activity in brain homogenate was reduced by manoalide, whereas phospholipase C activity was unaffected. At 60 min but not at 20 or 40 min after its injection, manoalide had significantly decreased by 50% incorporation of unesterified arachidonate into and turnover within brain phospholipids, taking into account dilution of the brain arachidonoyl-CoA pool by recycled arachidonate. Manoalide also increased by 100% the net rate of unesterified arachidonate incorporation into brain triacylglycerol. This study indicates that manoalide can be used to inhibit brain phospholipase A2 in vivo, and that phospholipase A2 plays a critical role in arachidonate turnover in brain phospholipids and neutral lipids.
Collapse
Affiliation(s)
- E Grange
- Laboratory of Neurosciences, National Institute on Aging, National Institutes of Health Bethesda, Maryland 20892-1582, USA
| | | | | | | |
Collapse
|
16
|
Platelet Arachidonic Acid Metabolism and Eicosanoid Receptors. ACTA ACUST UNITED AC 1997. [DOI: 10.1016/s1569-2558(08)60414-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
|
17
|
Smeets EF, Comfurius P, Bevers EM, Zwaal RF. Contribution of different phospholipid classes to the prothrombin converting capacity of sonicated lipid vesicles. Thromb Res 1996; 81:419-26. [PMID: 8907291 DOI: 10.1016/0049-3848(96)00014-x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The influence of different neutral phospholipids and cholesterol on the procoagulant properties of sonicated vesicles containing phosphatidylserine was studied, using the prothrombinase assay. When incorporated into membranes composed of phosphatidylcholine and phosphatidylserine, a stimulating effect of phosphatidylethanolamine and an inhibiting effect of sphingomyelin was observed. Cholesterol slightly increased the activities of all vesicles tested. In lipid vesicles with a composition mimicking that of the outer leaflet of the plasma membrane of the activated platelet, the inhibitory effect of sphingomyelin was overruled by an overall stimulatory effect of phosphatidylethanolamine, suggesting an accessory role for phosphatidylethanolamine in the procoagulant properties of activated platelets.
Collapse
Affiliation(s)
- E F Smeets
- Cardiovascular Research Institute Maastricht, Department of Biochemistry, University of Limburg, The Netherlands
| | | | | | | |
Collapse
|
18
|
Gaigé B, Simon MF, Klaébé A, Willson M, Rogalle P, Chap H. Inhibition of platelet type II phospholipase A2 by an acylamino phospholipid does not alter arachidonate liberation. JOURNAL OF LIPID MEDIATORS AND CELL SIGNALLING 1995; 11:281-93. [PMID: 7551684 DOI: 10.1016/0929-7855(95)00002-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
An acylamino phospholipid analogue (2-(R)-N-palmitoylnorleucinol-1-phosphoglycol or (R)-PNPG) was examined for its inhibitory effects against type II phospholipase A2 (PLA2) acting on membranes from Escherichia coli. Using two enzyme sources (rat platelet membranes or recombinant human type II PLA2), (R)-PNPG inhibited phospholipid hydrolysis to a maximal value of 80-85%, half-maximal effect being attained at a substrate/inhibitor molar ratio of 80-250. In contrast, (S)-PNPG was 12-fold less potent and thus provided a control for possible non-specific effects of these polar lipids. However, both analogues exerted only marginal effects on the liberation of [3H]arachidonic acid from rat platelets challenged with calcium ionophore A23187. Since, among various animal species, rat platelets contain by far the highest amounts of this enzyme, our data rule out any possible involvement of secretory PLA2 in arachidonic acid liberation from platelet phospholipids, cytosolic PLA2 appearing in this case as the best candidate able to regulate eicosanoid biosynthesis.
Collapse
Affiliation(s)
- B Gaigé
- INSERM Unité 326, Phospholipides Membranaires, Signalisation Cellulaire et Lipoprotéines, Hôpital Purpan, Toulouse, France
| | | | | | | | | | | |
Collapse
|
19
|
Julien M, Tournier JF, Tocanne JF. Basic Fibroblast Growth Factor Modulates the Aminophospholipid Translocase Activity Present in the Plasma Membrane of Bovine Aortic Endothelial Cells. ACTA ACUST UNITED AC 1995. [DOI: 10.1111/j.1432-1033.1995.0287i.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
20
|
Affiliation(s)
- E M Bevers
- Department of Biochemistry, Cardiovascular Research Institute, Maastricht, The Netherlands
| | | | | | | |
Collapse
|
21
|
Sphingomyelin transport to the cell surface occurs independently of protein secretion in rat hepatocytes. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(19)74284-7] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
|
22
|
Zachowski A. Phospholipids in animal eukaryotic membranes: transverse asymmetry and movement. Biochem J 1993; 294 ( Pt 1):1-14. [PMID: 8363559 PMCID: PMC1134557 DOI: 10.1042/bj2940001] [Citation(s) in RCA: 638] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- A Zachowski
- Institut de Biologie Physico-Chimique, Paris, France
| |
Collapse
|
23
|
Joo F, Chevy F, Colard O, Wolf C. The activation of rat platelets increases the exposure of polyunsaturated fatty acid enriched phospholipids on the external leaflet of the plasma membrane. BIOCHIMICA ET BIOPHYSICA ACTA 1993; 1149:231-40. [PMID: 8323942 DOI: 10.1016/0005-2736(93)90206-f] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Rat platelets have been hydrogenated in the presence of colloidal palladium adsorbed on the surface of the non water-soluble polymer polyvinylpolypyrrolidone. This non-permeating catalyst restricts hydrogenation of the fatty acyl double bonds of phospholipids only in the outer half of the plasma membrane. The pattern of hydrogenation of the molecular species present on the external side of the membrane is determined using desorption-chemical soft ionization-mass spectrometry (DCI-MS) before and after cell activation by the calcium ionophore A23187. The accessibility to the catalyst of the polyunsatured molecular species within each phospholipid class is compared for resting and activated cells. The abundance of polyunsaturated species of phosphatidyl-ethanolamine and -serine in the inner half of the resting biomembrane is confirmed in rat platelets. Phosphatidylcholine is especially rich in disaturated species in this membrane. The induced exposure of the polyunsaturated species of diacyl- and ether-phosphatidylethanolamine, and of phosphatidylserine on the external side of the membrane appears after activation by the calcium ionophore. A detailed quantitative analysis within a phospholipid class shows an unequal scrambling for diacyl-, alkyl-, alkenyl-phosphatidylethanolamine, and a variable involvement in the transmembrane redistribution following cell activation of the various molecular species as a function of the acyl moities.
Collapse
Affiliation(s)
- F Joo
- Kossuth Lajos University, Institute of Physical Chemistry, Debrecen, Hungary
| | | | | | | |
Collapse
|
24
|
Heemskerk JW, Feijge MA, Andree HA, Sage SO. Function of intracellular [Ca2+]i in exocytosis and transbilayer movement in human platelets surface-labeled with the fluorescent probe 1-(4-trimethylammonio)phenyl)-6-phenyl-1,3,5-hexatriene. BIOCHIMICA ET BIOPHYSICA ACTA 1993; 1147:194-204. [PMID: 8476913 DOI: 10.1016/0005-2736(93)90004-j] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Ellipsometry indicated that 1-(4-(trimethylammonio)phenyl-6-phenylhexa-1,3,5-triene (TMA-DPH) bound to platelets in a reversible and saturable way. Accordingly, the fluorescence intensity (F) of a suspension of TMA-DPH-labeled platelets was described as a quantity, determined by the amount of TMA-DPH bound to the platelet surface. Most platelet activators elevated F to a degree that correlate well with the secretion of serotonin evoked by these activators. The increase in F levels reflected the increase in outer membrane surface area following exocytosis. However, activators that evoked prolonged (> 2.5 min) and strong (> 600 nM) elevations of cytosolic [Ca2+]i increased F to levels that were much higher than expected from the maximal increase in surface area due to exocytosis. This high increase in F was caused by inward transbilayer movement of TMA-DPH over the plasma membrane and the subsequent labeling of cytosolic membrane sides. The kinetics of exocytosis and changes in cytosolic [Ca2+]i were studied by stopped-flow mixing of platelets with agonist. Thrombin-induced exocytosis had a delay of only 3 s, which was shortened when external CaCl2 or ADP was present. This correlated well with a faster rise in [Ca2+]i in the presence of CaCl2 or ADP, indicating that exocytosis was linked in time to elevation of [Ca2+]i. By itself, ADP was unable to evoke exocytosis and it elicited a [Ca2+]i transient of much shorter duration than thrombin, but with similar maximum. We concluded that both exocytosis and transbilayer movement were associated with elevation of [Ca2+]i: exocytosis required a moderate, relatively prolonged rise and transbilayer movement was accompanied by a stronger rise of even longer duration. Influx of external Ca2+ was essential for transbilayer movement, but not for exocytosis.
Collapse
Affiliation(s)
- J W Heemskerk
- Department of Biochemistry/Human Biology, University of Limburg, Maastricht The Netherlands
| | | | | | | |
Collapse
|
25
|
Bassé F, Gaffet P, Rendu F, Bienvenüe A. Translocation of spin-labeled phospholipids through plasma membrane during thrombin- and ionophore A23187-induced platelet activation. Biochemistry 1993; 32:2337-44. [PMID: 8443175 DOI: 10.1021/bi00060a027] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
After incorporation of spin-labeled phosphatidylcholine, phosphatidylserine, and phosphatidylethanolamine analogues in the outer leaflet of the plasma membrane in resting platelets, more than 90% amino-head analogues accumulated within 30 min in the inner leaflet by aminophospholipid translocase activity, while choline analogues mostly remained on the outer leaflet. Platelets were then activated by thrombin or Ca2+ ionophore A23187. No outward movement of internally located spin-labeled aminophospholipids was observed during thrombin-induced activation, whereas the influx of externally located probes increased slightly. During A23187-mediated activation, similar slightly increased influx was observed, while 40-50% of the initially internally located aminophospholipids could then be extracted from the outer leaflet. This sudden exposure on the outer face was dependent on an increase in intracellular Ca2+ and achieved in less than 2 min at 37 degrees C. Inhibition of translocase activity by N-ethylmaleimide did not induce any aminophospholipid outflux. When probes were incorporated on the outer face of the plasma membrane in resting platelets, they were still fully accessible from the extracellular medium after A23187-induced activation. Moreover, they were distributed between the vesicles and remnant platelets in proportion to the external membrane phospholipidic content in each structure. This suggested that no scrambling of plasma membrane leaflets occurred during the vesicle blebbing. Moreover, the spin-labeled aminophospholipids exposure rate and amplitude were unchanged when vesicle formation was inhibited by the calpain inhibitor calpeptin. These results indicate that loss of asymmetry thus inducing generation of a catalytic surface is not the consequence of vesicle formation. Conversely, we propose that vesicle shedding is an effect of PL transverse redistribution and calpain-mediated proteolysis during activation.
Collapse
Affiliation(s)
- F Bassé
- URA 530 CNRS, CP 107, Université Montpellier II, France
| | | | | | | |
Collapse
|
26
|
Cezanne L, Navarro L, Tocanne JF. Isolation of the plasma membrane and organelles from Chinese hamster ovary cells. BIOCHIMICA ET BIOPHYSICA ACTA 1992; 1112:205-14. [PMID: 1457453 DOI: 10.1016/0005-2736(92)90393-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Two methods are described enabling the plasma membrane from Chinese hamster ovary (CHO) cells to be obtained rapidly, relatively pure and with a good yield. In both cases, cells were disrupted by nitrogen cavitation in an isoosmotic buffer either at pH 5.4 or at pH 7.4. In the first approach, cells were lysed at pH 7.4 and the plasma membrane and cell organelles were isolated on a self-generated gradient of Percoll, at neutral pH. Mitochondria and endoplasmic reticulum were recovered in the denser fractions, plasma membrane fragments were found in the lighter fractions, but always contaminated by lysosomes. Because lysosomes were found to sediment in acidic conditions, cells were lysed at pH 5.4 and presedimentation (1500 x g) of the cell homogenate at the same pH enabled more than 80% of the lysosomes to be removed. Then, ultracentrifugation of the supernatant over a Percoll gradient at neutral pH yielded plasma membrane fractions practically free of lysosomes with an enrichment ratio of 3 and fractions of mitochondria and endoplasmic reticulum with enrichment ratios of 17 and 6, respectively. A major problem was encountered in the final step of elimination of Percoll from the purified plasma membrane fractions. Whatever the technique used for eliminating Percoll, plasma membranes were observed to be contaminated by a Percoll constituent which prevented further purification and biochemical identification of the lipids extracted from these membrane fractions to be carried out. A second method of plasma membrane preparation was tested consisting first in the coating of the cell surface with positive colloidal silica which was stabilized by an anionic polymer. Then, and through differential centrifugations, plasma membrane fractions were easily obtained within less than 1 h, with a yield of 65% and an enrichment ratio of 7. The coating pellicle was quantitatively removed thus enabling any biochemical manipulation of the plasma membrane to be carried out. The lipids present in the plasma membrane of CHO cells were analyzed and are described, both in terms of headgroup and acyl chain composition.
Collapse
Affiliation(s)
- L Cezanne
- Centre de Recherche de Biochimie et Génétique Cellulaires du CNRS, Laboratoire de Pharmacologie et Toxicologie Fondamentales, Toulouse, France
| | | | | |
Collapse
|
27
|
Ostfeld I, Dadosh-Goffer N, Borokowski S, Talmon J, Mani A, Zor U, Lahav J. Lupus anticoagulant antibodies inhibit collagen-induced adhesion and aggregation of human platelets in vitro. J Clin Immunol 1992; 12:415-23. [PMID: 1287033 DOI: 10.1007/bf00918853] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The effect of circulating lupus anticoagulant on platelet interaction with collagen and other proteins was tested, with the aim of understanding the role of membrane phospholipids in platelet function. Plasma samples from 26 systemic lupus erythematosus (SLE) patients, containing circulating lupus anticoagulant (LAC), were examined for their effect on adhesion and aggregation of normal human platelets. We find that SLE plasma, but not normal plasma, inhibits platelet adhesion to collagen in a concentration-dependent manner. At a plasma concentration of 1% the inhibition was 73 +/- 9% (mean +/- SD). In sharp contrast, there was no effect on platelet adhesion to fibronectin. Purified IgG from the same plasma samples also had an inhibitory effect. At 15 micrograms/ml (comparable in IgG concentration to 0.1% plasma) it inhibited adhesion to collagen by 33 +/- 11%. Inhibition could be abolished by preincubation of the LAC-containing plasma with cardiolipin (CL), phosphatidylinositol (PI), and, to a lesser extent, phosphatidylserine (PS) but not with phosphatidylcholine (PC) or phosphatidylethanolamine (PE). Inhibition could also be abolished by preincubation of the LAC-containing plasma with a 10-fold excess of washed normal platelets. The effect of 1% LAC plasma on platelet aggregation was as striking, showing 79 +/- 26% inhibition of collagen-induced aggregation, and it could also be abolished by preincubation of the LAC plasma with cardiolipin. In contrast, the effect of LAC plasma on thrombin-induced aggregation was rather modest. Our results indicate that antiphospholipid antibodies interfere with platelet adhesion and stimulation by collagen in vitro and point to an important role of external plasma membrane phospholipids, particularly PI, in collagen-induced platelet activation.
Collapse
Affiliation(s)
- I Ostfeld
- Department of Hormone Research, Weizmann Institute of Science, Rehovot, Israel
| | | | | | | | | | | | | |
Collapse
|
28
|
Boué D, Viratelle OM. Platelet membrane phosphatidylinositol kinase activity. Triton X-100 effects provide evidence for intramicellar reaction. BIOCHIMICA ET BIOPHYSICA ACTA 1992; 1103:120-6. [PMID: 1309657 DOI: 10.1016/0005-2736(92)90065-t] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Phosphatidylinositol (PI) kinase activity of platelet membranes was solubilized and partially purified by anion-exchange chromatography to measure the initial enzymatic rates. Kinetic studies were performed in the presence of Triton X-100 to obtain mixed micelles. The partially purified enzyme exhibited a Michaelian behaviour towards ATP, with a Km of 58 microM. The enzymatic rates were dependent upon Triton concentrations. Upon increasing its concentration, this detergent exhibited an activating effect followed by an inhibitory one. The optimal micellar Triton concentration was proportionnal to the PI concentration used in the assay. Conversely, the behaviour of the enzyme towards PI was dependent upon the Triton concentration. However, when PI concentration was expressed as its surfacic concentration within the micelles, the activity became independent of the detergent concentration, and a Km value of 0.09 mol/mol was estimated. Therefore, in vitro phosphorylation of phosphatidylinositol by PI kinase is rate-limited by an intramicellar reaction, and provides a study model for the in vivo reaction.
Collapse
Affiliation(s)
- D Boué
- Institut de Biochimie Cellulaire et Neurochimie, Centre National de la Recherche Scientifique, Bordeaux, France
| | | |
Collapse
|
29
|
Schroit AJ, Zwaal RF. Transbilayer movement of phospholipids in red cell and platelet membranes. BIOCHIMICA ET BIOPHYSICA ACTA 1991; 1071:313-29. [PMID: 1958692 DOI: 10.1016/0304-4157(91)90019-s] [Citation(s) in RCA: 256] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- A J Schroit
- Department of Cell Biology, University of Texas M.D. Anderson Cancer Center, Houston
| | | |
Collapse
|
30
|
Sánchez-Yagüe J, Cabezas JA, Llanillo M. Fatty acid composition of subcellular particles from sheep platelets and topological distribution of phosphatidylethanolamine fatty acids in the plasma membrane. Lipids 1991; 26:878-83. [PMID: 1805091 DOI: 10.1007/bf02535971] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The fatty acid composition of individual phospholipids in subcellular fractions of sheep platelets and the asymmetrical distribution of phosphatidylethanolamine (PE) fatty acyl chains across the plasma membrane were examined. The main fatty acids of total lipid extracts were oleic (18:1; 32-41%), linoleic (18:2, 10-17%), stearic (18:0; 13-15%), palmitic (16:0; 11-15%) and arachidonic (20:4; 8-12%) acids, with a saturated/unsaturated ratio of about 0.4. Each phospholipid class had a distinct fatty acid pattern. Sphingomyelin (SM) showed the highest degree of saturation (50%), with large proportions of behenic (22:0), 18:0 and 16:0 acids. The main fatty acid in PE, phosphatidylserine (PS) and phosphatidylcholine (PC) was 18:1n-9. Our findings suggest that fatty acids are asymmetrically distributed between the choline versus the non-choline phospholipids, and also between plasma membranes and intracellular membranes. The transbilayer distribution of PE fatty acids in plasma membranes from non-stimulated sheep platelets was investigated using trinitrobenzene-sulfonic acid (TNBS). A significant degree of asymmetry was found, which is a new observation in a non-polar cell. The PE molecules from the inner monolayer contained higher amounts of 18:2 and significantly less 18:1 and 20:5 than those found in the outer monolayer, although no major differences were detected in the transbilayer distribution of total unsaturated versus saturated PE acyl chains.
Collapse
Affiliation(s)
- J Sánchez-Yagüe
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Salamanca, Spain
| | | | | |
Collapse
|
31
|
Abstract
Membranes allow the rapid passage of unchanged lipids. Phospholipids on the other hand diffuse very slowly from one monolayer to another with a half-time of several hours. This slow spontaneous movement in a pure lipid bilayer can be selectively modulated in biological membranes by intrinsic proteins. In microsomes, and probably in bacterial membranes, non-specific phospholipid flippases allow the rapid redistribution of newly synthesized phospholipids. In eukaryotic plasma membranes, aminophospholipid translocase selectively pumps phosphatidylserine (PS) and phosphatidylethanolamine (PE) from the outer to the inner leaflet and establishes a permanent lipid asymmetry. The discovery of an aminophospholipid translocase in chromaffin granules proves that eukaryotic organelles may also contain lipid translocators.
Collapse
Affiliation(s)
- A Zachowski
- Institut de Biologie Physico-Chimique, Paris, France
| | | |
Collapse
|
32
|
Bevers EM, Verhallen PF, Visser AJ, Comfurius P, Zwaal RF. Bidirectional transbilayer lipid movement in human platelets as vizualized by the fluorescent membrane probe 1-[4-(trimethylammonio)phenyl]-6-phenyl-1,3,5-hexatriene. Biochemistry 1990; 29:5132-7. [PMID: 2378868 DOI: 10.1021/bi00473a019] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Transbilayer movement of the fluorescent membrane probe TMA-DPH [1-[4-(trimethylammonio)phenyl]-6-phenyl-1,3,5-hexatriene] in the plasma membrane of human platelets was investigated by measuring fluorescence intensity and fluorescence decay. Labeling of unstimulated platelets by TMA-DPH results in a rapid increase in fluorescence intensity, leveling off within 1 min. Dilution of platelets into buffer without TMA-DPH leads to an almost complete rapid efflux of TMA-DPH, indicating that TMA-DPH labels only the outer leaflet of the plasma membrane. Transbilayer movement of the fluorescent probe in unstimulated platelets could be observed upon prolonged incubation and occurs with a t1/2 of 60-90 min. Stimulation of platelets with thrombin directly after the initial rapid uptake of TMA-DPH results in a fast increase in membrane-bound TMA-DPH, fully explained by the increase in plasma membrane caused by secretion of intracellular storage organelles. No indications for increased transbilayer movement of the probe were found, since dilution of thrombin-stimulated TMA-DPH-labeled platelets into buffer without TMA-DPH indicated no uptake of TMA-DPH by intracellular membranes. In contrast to thrombin, stimulation of TMA-DPH-labeled platelets with the Ca2(+)-ionophore ionomycin results in a much larger increase in fluorescence intensity. This process is accompanied by labeling of intracellular membranes as indicated by incomplete efflux of TMA-DPH after dilution of the stimulated platelets. Thus, stimulation of platelets by ionomycin gives rise to rapid and massive inward movement of TMA-DPH (t1/2 approximately 10-12 s). Prolonged incubation of platelets in the absence of any stimulus allows labeling of the total lipid pool, including intracellular membranes.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- E M Bevers
- Department of Biochemistry, University of Limburg, Maastricht, The Netherlands
| | | | | | | | | |
Collapse
|
33
|
Gassama-Diagne A, Fauvel J, Chap H. Calcium-independent phospholipases from guinea pig digestive tract as probes to study the mechanism of lipocortin. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(19)39564-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
|
34
|
Corbett R, Menez J, Leonard B. The effect of chronic alcohol administration on platelet [3H]5-hydroxytryptamine uptake and membrane lipid composition. Neurochem Int 1990; 16:95-8. [DOI: 10.1016/0197-0186(90)90128-g] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/1987] [Accepted: 07/07/1989] [Indexed: 11/25/2022]
|
35
|
Record M, Ribbes G, Tercé F, Chap H. Subcellular localization of phospholipids and enzymes involved in PAF-acether metabolism. J Cell Biochem 1989; 40:353-9. [PMID: 2506197 DOI: 10.1002/jcb.240400311] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The biosynthesis of platelet-activating factor (PAF-acether or 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine) through the remodeling pathway was investigated at the subcellular level in two different cell lines. In human neutrophils, plasma membrane was isolated not only from granules, but also from internal membranes related to endoplasmic reticulum. Interestingly, the latter exhibited enhanced acetyltransferase upon neutrophil stimulation with ionophore A23187. A similar study was undertaken on the tumor strain Krebs-II cells. The enzyme acetyltransferase was found to be located only on an endoplasmic reticulum subfraction, whereas most alkylacyl-GPC, the source of PAF-precursor alkyl-lyso-GPC, was located in the plasma membrane inner leaflet. The topographical separation of enzyme and precursor emphasizes the central role of the intracellular phospholipase A2 in providing lyso-PAF to the acetyltransferase to form PAF-acether.
Collapse
Affiliation(s)
- M Record
- INSERM Unité 101, Biochimie des Lipides, Hôpital Purpan, Toulouse, France
| | | | | | | |
Collapse
|
36
|
Shapiro SZ, Webster P. Coated vesicles from the protozoan parasite Trypanosoma brucei: purification and characterization. THE JOURNAL OF PROTOZOOLOGY 1989; 36:344-9. [PMID: 2570143 DOI: 10.1111/j.1550-7408.1989.tb05524.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A procedure was developed to purify a coated vesicle fraction from the protozoan parasite Trypanosoma brucei. Electron microscopy revealed a difference between T. brucei coated vesicles and clathrin-coated vesicles from other eukaryotes: trypanosome vesicles were larger (100 to 150 nm in diameter) and contained an inner coat of electron-dense material in addition to the external coat. Evidence suggests that the internal coat is the parasite's variant surface glycoprotein (VSG) coat. The SDS-PAGE analysis shows the major protein of T. brucei coated vesicles has a molecular mass of 61 kD, similar to VSG; this protein was recognized in an immunoblot by anti-VSG serum. Trypanosome coated vesicles also contain a protein which comigrates with the major protein (clathrin) of coated vesicles purified from rat brains. However, this protein is a minor component and it is not serologically cross-reactive with mammalian clathrin. Immunoblot analysis demonstrated that the parasite vesicles contained host IgG, IgM, and serum albumin.
Collapse
Affiliation(s)
- S Z Shapiro
- International Laboratory for Research on Animal Diseases (ILRAD), Nairobi, Kenya
| | | |
Collapse
|
37
|
Shiao YJ, Chen JC, Wang CT. The solubilization and morphological change of human platelets in various detergents. BIOCHIMICA ET BIOPHYSICA ACTA 1989; 980:56-68. [PMID: 2923900 DOI: 10.1016/0005-2736(89)90200-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The solubilization of human gel-filtered platelets by octyl glucoside, Triton X-100, dodecylsulfate, and deoxycholate was compared from the analysis of (1) cell lysis, (2) marker leakiness, and (3) component solubility. These analyses all revealed that the effect of detergent concentration on the solubilization of platelets by these detergents was exerted in three stages, i.e., the prelytic, lytic, and complete platelet-lysis stages. These analyses also indicated several differences among platelets in these detergents. (i) The ratio of the platelet-saturation concentration (PSC) to critical micellar concentration (CMC) was about 1/2 for octyl glucoside. Triton X-100 and dodecylsulfate, while it was close to 1 for deoxycholate. (ii) Platelets in octyl glucoside. Triton X-100, and dodecylsulfate all showed parallel curves in cell lysis, protein solubilization and marker leakiness, while the platelet lysis in deoxycholate was identical to the phospholipid solubilization. (iii) The solubility curves of various components in Triton X-100 and deoxycholate were parallel. However, the solubility of cholesterol in octyl glucoside was lower than that of protein and phospholipid. In dodecylsulfate, the solubility of phospholipid and cholesterol was very low in comparison with that of protein. In addition, morphological studies using scanning electron microscopy (scanning EM) revealed that the solubilization by octyl glucoside or Triton X-100 might occur via membrane area expansion. On the other hand, the solubilization by dodecylsulfate or deoxycholate showed membrane vesiculation prior to cell lysis. Moreover, in the prelytic stage, the morphological change in platelets in octyl glucoside showed only concentration dependence by swelling to an ellipsoid and then to a sphere. However, the morphological change in platelets in the other three detergents was dependent not only on the detergent concentration but also on prolonged incubation. Specifically, in Triton X-100, the cells initially changed to spiculate discs and then reached their final shape as swollen discs with surface invagination. In dodecylsulfate and deoxycholate the morphological changes were almost the same. The cell initially deformed in shape to a spiculate disc and finally to a stretched-out flat form. The results are discussed according to the bilayer couple hypothesis. Also, in the prelytic stage, these detergents caused inhibition of the response of platelets to collagen and ADP-fibrinogen.
Collapse
Affiliation(s)
- Y J Shiao
- Institute of Life Science, National Tsing Hua University, Hsinchu, Taiwan, China
| | | | | |
Collapse
|
38
|
Lange Y, Swaisgood MH, Ramos BV, Steck TL. Plasma Membranes Contain Half the Phospholipid and 90% of the Cholesterol and Sphingomyelin in Cultured Human Fibroblasts. J Biol Chem 1989. [DOI: 10.1016/s0021-9258(19)84918-9] [Citation(s) in RCA: 193] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
|
39
|
Arita H, Nakano T, Hanasaki K. Thromboxane A2: its generation and role in platelet activation. Prog Lipid Res 1989; 28:273-301. [PMID: 2534976 DOI: 10.1016/0163-7827(89)90002-7] [Citation(s) in RCA: 149] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- H Arita
- Shionogi Research Laboratories, Shionogi & Co. Ltd, Osaka, Japan
| | | | | |
Collapse
|
40
|
Pelletier X, Freysz L, Leray C. Topological distribution of choline phospholipid fatty acids in trout intestinal brush-border membrane. BIOCHIMICA ET BIOPHYSICA ACTA 1988; 942:125-30. [PMID: 3382653 DOI: 10.1016/0005-2736(88)90281-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The transbilayer distribution of choline phospholipids in trout intestinal brush-border membrane has been investigated using phospholipase C (from Clostridium welchii). In the middle intestine, 84% of phosphatidylcholine (PC) and 60% of sphingomyelin (SP) are located in the outer membrane leaflet. In the posterior intestine, 89% of PC and 52% of SP are located in the outer membrane leaflet. The externally located PC molecular species are (n - 3) fatty acid-rich in both parts of the intestine. While the sphingomyelin molecular species containing 24:1(n - 9) are exclusively located in the outer leaflet in the middle intestine, those containing 14:0 are more abundant in the same leaflet but in the posterior intestine. This strongly asymmetric distribution of both choline phospholipids may have numerous consequences on the brush-border membrane characteristics.
Collapse
Affiliation(s)
- X Pelletier
- Centre de Neurochimie du CNRS, Strasbourg, France
| | | | | |
Collapse
|
41
|
Verhallen PF, Bevers EM, Comfurius P, Zwaal RF. Fluoride-dependent calcium-induced platelet procoagulant activity shows that calpain is involved in increased phospholipid transbilayer movement. BIOCHIMICA ET BIOPHYSICA ACTA 1988; 942:150-8. [PMID: 2838083 DOI: 10.1016/0005-2736(88)90284-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Treatment of platelets with fluoride (10 mM) was found to result in a transient increase in Ca2+-permeability of the platelet plasma membrane. This phenomenon was used to provide supplementary evidence for the suggestions made earlier (Comfurius et al. (1985) Biochim. Biophys. Acta 815, 143; Verhallen et al. (1987) Biochim. Biophys. Acta 903, 206), that cytoskeletal disrupture by calpain is involved in the process leading to transbilayer movement of phosphatidylserine during expression of platelet procoagulant activity. This was achieved by relating both calpain activity and exposure of phosphatidylserine with platelet procoagulant activity. It was found that only upon addition of extracellular Ca2+ to fluoride-treated platelets, procoagulant activity, expressed as prothrombinase activity, and calpain activity, estimated from protein patterns after gel electrophoresis, were generated. Both Ca2+-inducible prothrombinase activity and calpain activity followed an identical time-course during incubation with fluoride: after a time-lag of about 10 min they sharply increased towards a peak level. Upon further incubation with fluoride, both activities decreased towards a final plateau, still above basal level. The presence of leupeptin during incubation with fluoride was found to inhibit Ca2+-inducible calpain activity and prothrombinase activity in an identical way. Ca2+-inducible exposure of phosphatidylserine, as determined with extracellular phospholipase A2, showed a similar pattern as Ca2+-inducible calpain activity and prothrombinase activity. From the strict parallelism between prothrombinase activity, calpain activity and exposure of phosphatidylserine, it is concluded that calpain plays an important role in the activation-dependent transbilayer movement of phosphatidylserine during expression of platelet procoagulant activity. It is suggested that degradation of the platelet membrane-skeleton by calpain disturbs the structural organization of the lipid bilayer of the platelet plasma membrane leading to enhanced transbilayer movement of phospholipids and appearance of phosphatidylserine at the platelet outer surface.
Collapse
Affiliation(s)
- P F Verhallen
- Department of Biochemistry, University of Limburg, Maastricht, The Netherlands
| | | | | | | |
Collapse
|
42
|
Payrastre B, Plantavid M, Etievan C, Ribbes G, Carratero C, Chap H, Douste-Blazy L. Characterization of plasma membranes from A431 cells, isolated by self-generating Percoll gradient: a rapid isolation procedure to obtain plasma membranes with functional epidermal growth factor receptors. BIOCHIMICA ET BIOPHYSICA ACTA 1988; 939:355-65. [PMID: 3258534 DOI: 10.1016/0005-2736(88)90081-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Plasma membranes have been isolated from the human epidermoid carcinoma cell line A431 by a rapid fractionation of lysate on Percoll density gradient at pH 9.6. Endoplasmic reticulum, lysosomes and mitochondria sedimented at the bottom of gradient whereas plasma membranes focused at low density, as shown with specific markers. Plasma membranes displayed a 4.5- and 4.4-fold enrichment in [3H]concanavalin A and 5'-nucleotidase, respectively. This proteic fraction was further characterized by its lipid composition and phospholipid analysis. The cholesterol/phospholipid molar ratio was 0.45 in plasma membranes against 0.19 in lysate. Sphingomyelin increased from 7.5% of total phospholipids in lysate to 16.2% in plasma membranes, as well as phosphatidylserine which displayed a 1.5-fold enrichment in the plasma membrane fraction. This was at the expense of phosphatidylcholine (45.2% in lysate, against 35% in plasma membranes). Electron microscopy of the isolated material showed vesicles essentially free from endoplasmic reticulum and organelles. These plasma membranes retained the ability to bind 125I-labelled epidermal growth factor (125I-EGF) with a Kd = 4.7 nM and Bmax = 63 pmol/mg protein. EGF binding resulted in a stimulation of the phosphorylation protein reaction in the presence of [gamma-32P]ATP and sodium dodecyl sulfate polyacrylamide gels of phosphorylated proteins indicated that the radioactivity of the major band of molecular weight 170,000 was clearly enhanced by EGF binding. These results indicate that the EGF receptor and its intrinsic protein kinase activity were preserved during our plasma membrane isolation procedure.
Collapse
Affiliation(s)
- B Payrastre
- INSERM Unité 101, Hôpital Purpan, Toulouse, France
| | | | | | | | | | | | | |
Collapse
|
43
|
Chap H, Comfurius P, Bevers EM, Fauvel J, Vicendo P, Douste-Blazy L, Zwaal RF. Potential anticoagulant activity of lipocortins and other calcium/phospholipid binding proteins. Biochem Biophys Res Commun 1988; 150:972-8. [PMID: 2963637 DOI: 10.1016/0006-291x(88)90724-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Thrombin generation was determined in the presence of phospholipids, coagulation factors Xm, Vm and II (prothrombin), calcium, and various calcium/phospholipid bindings proteins, including lipocortins I and II, 35 kDa calelectrin, and 32.5 kDa endonexin. All of these proteins induced a dose-dependent inhibition of thrombin generation similar to the inhibition of pig pancreas phospholipase A2. It is suggested that the ability of lipocortins and other related proteins to interact with anionic phospholipids in the presence of Ca++ is responsible for both their anticoagulant and anti-phospholipase A2 activity.
Collapse
Affiliation(s)
- H Chap
- INSERM Unité 101, Biochimie des Lipides, Hôpital Purpan, Toulouse, France
| | | | | | | | | | | | | |
Collapse
|
44
|
Affiliation(s)
- K J Kako
- Department of Physiology, School of Medicine, University of Ottawa, Ontario, Canada
| |
Collapse
|
45
|
Lamant V, Mauco G, Braquet P, Chap H, Douste-Blazy L. Inhibition of the metabolism of platelet activating factor (PAF-acether) by three specific antagonists from Ginkgo biloba. Biochem Pharmacol 1987; 36:2749-52. [PMID: 2820421 DOI: 10.1016/0006-2952(87)90259-0] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Washed rabbit platelet suspensions were incubated in the presence of 1-[3H]O-alkyl-2-acetyl-sn-glycero-3-phosphocholine ([3H] PAF-acether), which was metabolized into 1-[3H]O-alkyl-2-acyl-sn-glycero-3-phosphocholine (alkylacyl-GPC) through the sequential action of cytosolic acetylhydrolase and membrane transacylase. Within 60 min at 37 degrees, percentage of [3H] PAF-acether metabolized was 50.3 +/- 5.2% (9 experiments). This conversion was inhibited in a dose-dependent manner by various concentrations of ginkgolides A, B and C (BN 52020, 52021, 52022) known as specific antagonists of PAF-acether. The three compounds displayed the following order of potency: BN 52021 (IC50 = 3.6 X 10(-6) M) greater than BN 52020 (IC50 = 9.7 X 10(-6) M) greater than BN 52022 (IC50 = 37.6 X 10(-6) M). As this order is the same as that previously defined for inhibition of platelet aggregation to PAF-acether or for inhibition of PAF-acether binding to platelets, our data bring further support to the view that PAF-acether metabolism in platelets involves in some way its binding to its membrane receptor.
Collapse
|
46
|
Pelletier X, Mersel M, Freysz L, Leray C. Topological distribution of aminophospholipid fatty acids in trout intestinal brush-border membrane. BIOCHIMICA ET BIOPHYSICA ACTA 1987; 902:223-8. [PMID: 3620457 DOI: 10.1016/0005-2736(87)90299-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The transbilayer distribution of aminophospholipids in trout intestinal brush-border membrane has been investigated using trinitrobenzene sulfonic acid (TNBS). In the middle intestine, phosphatidylethanolamine (PE) is symmetrically distributed between the two leaflets while 68% of the phosphatidylserine (PS) are located in the inner membrane leaflet. In the posterior intestine, 64% of the PE and 69% of the PS are located in the inner membrane leaflet. When asymmetrically distributed, the inner species of PE and PS have a higher content of 22:6(n-3) than the outer ones. This asymmetric distribution of docosahexaenoic acid in trout intestinal brush-border membrane might be related to the rod-like shape of the microvillus membrane and to its metabolism to hydroxylated derivatives.
Collapse
|
47
|
Schlegel RA, Williamson P. Membrane phospholipid organization as a determinant of blood cell-reticuloendothelial cell interactions. J Cell Physiol 1987; 132:381-4. [PMID: 3305527 DOI: 10.1002/jcp.1041320229] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
|
48
|
Hall ER, Manner CE, Carinhas J, Snopko R, Rafelson M. Selective internalization of arachidonic acid by endothelial cells. Biochem J 1987; 245:151-7. [PMID: 2822011 PMCID: PMC1148094 DOI: 10.1042/bj2450151] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The asymmetric distribution of phospholipids in bovine endothelial-cell membranes was probed with 2,4,6-trinitrobenzenesulphonate and purified phospholipase A2. The data suggest that phosphotidylethanolamine is primarily located in the inner lipid bilayer, as reported for other cell types. Stearic acid is taken up by the endothelial cells and is randomly distributed among the membrane phospholipids. In contrast, the polyunsaturated fatty acids (arachidonic, eicosatrienoic and eicosapentaenoic acids) have initial incorporation into the phosphatidylcholine fraction. These fatty acids then undergo a time-dependent transfer from phosphatidylcholine to phosphatidylethanolamine. Thus we propose that endothelial cells possess a mechanism for the selective internalization of polyunsaturated fatty acids.
Collapse
Affiliation(s)
- E R Hall
- Division of Hematology/Oncology, University of Texas Medical School, Houston 77225
| | | | | | | | | |
Collapse
|
49
|
Mauco G, Dajeans P, Chap H, Douste-Blazy L. Subcellular localization of inositol lipids in blood platelets as deduced from the use of labelled precursors. Biochem J 1987; 244:757-61. [PMID: 3446190 PMCID: PMC1148060 DOI: 10.1042/bj2440757] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
1. By rapid fractionation of blood platelet lysates on Percoll density gradients at alkaline pH (9.6), a very pure plasma-membrane fraction was obtained, as well as discrimination between endoplasmic reticulum and lysosomes. 2. Labelling of intact platelets with [32P]Pi followed by subcellular fractionation showed an exclusive localization of all inositol lipids in the plasma membrane. 3. Preincubation of whole platelets with myo-[3H]inositol in a buffer containing 1 mM-MnCl2 allowed incorporation of the label into PtdIns (phosphatidylinositol) of both plasma and endoplasmic-reticulum membrane, whereas [3H]PtdIns4P (phosphatidylinositol 4-phosphate) and [3H]PtdIns(4,5)P2 (phosphatidylinositol 4,5-bisphosphate) were exclusively found on the plasma membrane. 4. It is concluded that PtdIns4P and PtdIns(4,5)P2 are exclusively localized in the plasma membrane, whereas PtdIns is present in both plasma and endoplasmic-reticulum membranes. This could provide an explanation for previously reported data on hormone-sensitive and -insensitive inositol lipid pools.
Collapse
Affiliation(s)
- G Mauco
- INSERM Unité 101, Hôpital Purpan, Toulouse, France
| | | | | | | |
Collapse
|
50
|
Wang CT, Tsai WJ, Chang SM, Shiao YJ, Yang CC. Different susceptibilities of platelet phospholipids to various phospholipases and modifications induced by thrombin. Possible evidence of rearrangement of lipid domains. BIOCHIMICA ET BIOPHYSICA ACTA 1987; 899:205-12. [PMID: 3580366 DOI: 10.1016/0005-2736(87)90401-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
On the membrane surface of the human platelet, phosphatidylcholine (PC) and phosphatidylethanolamine (PE) were hydrolyzed to different extents by the snake venom phospholipases A2 of varying pI values. The susceptibility of platelet phospholipids to basic phospholipase A2 of Naja nigricollis (pI 10.6) has been reported (Wang et al. (1986) Biochim. Biophys. Acta 856, 244-258). The susceptibilities of platelet phospholipids to acidic phospholipase A2 of Naja naja atra (pI 5.2) and to neutral phospholipase A2 of Hemachatus haemachatus (pI 7.3) were investigated in this study. In gel-filtered platelets, acidic phospholipase A2 hydrolyzed 35% PC and 10% PE, while neutral phospholipase A2 hydrolyzed 18% PC and 3% PE. In thrombin-induced shape-changed platelets, acidic phospholipase A2 hydrolyzed 20% PC and 10% PE, while neutral phospholipase A2 hydrolyzed 15% PC and 6% PE. In thrombin-activated platelets, acidic phospholipase A2 hydrolyzed 25% PC and 7% PE, while neutral phospholipase A2 hydrolyzed 25% PC and 10% PE. Sequential lipid hydrolysis experiments showed that basic phospholipase A2 of Naja nigricollis could hydrolyze the remaining PC and PE in the membrane previously treated with the neutral enzyme. The results may mean that: the PC and the PE domains exist on the platelet membrane surface; and the lipid domains on the membrane surface of resting platelets are rearranged by thrombin.
Collapse
|