N-linked glycosylation of macrophage-derived PAF-AH is a major determinant of enzyme association with plasma HDL
Human plasma PAF-AH (platelet-activating factor-acetylhydrolase) is a Ca2+-independent phospholipase A2 of hematopoietic origin associated with LDL and HDL; it degrades PAF and oxidizes phospholipids. We show that human macrophages synthesize PAF-AH as a premedial Golgi precursor containing high man...
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| Format: | Article |
| Language: | English |
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Elsevier
2001-10-01
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| Series: | Journal of Lipid Research |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S0022227520322197 |
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| author | Alexandros D. Tselepis Sonia-Athena P. Karabina Dominique Stengel Remi Piédagnel M. John Chapman Ewa Ninio |
| author_facet | Alexandros D. Tselepis Sonia-Athena P. Karabina Dominique Stengel Remi Piédagnel M. John Chapman Ewa Ninio |
| author_sort | Alexandros D. Tselepis |
| collection | DOAJ |
| description | Human plasma PAF-AH (platelet-activating factor-acetylhydrolase) is a Ca2+-independent phospholipase A2 of hematopoietic origin associated with LDL and HDL; it degrades PAF and oxidizes phospholipids. We show that human macrophages synthesize PAF-AH as a premedial Golgi precursor containing high mannose N-linked glycans. Secreted PAF-AH possesses a molecular mass of ~55 kDa and contains mature N-linked glycans. Secreted PAF-AH activity (90 ± 4% of the total) bound to a wheat germ lectin column and could be eluted with N-acetylglucosamine, whereas digestion with N-acetylneuraminidase II completely abolished enzyme absorption. Tunicamycin significantly reduced cell-associated PAF-AH activity and inhibited enzyme secretion; but it did not alter the ratio of secreted to cell-associated enzyme (1.8 at 6 h and 3.1 at 24 h), suggesting that glycosylation is not essential for PAF-AH secretion. Digestion of cell-associated PAF-AH or secreted PAF-AH with peptide N-glycosidase F affected neither catalytic activity nor its resistance to proteolysis with trypsin or proteinase K; in addition, it did not affect PAF-AH association with LDL, but significantly increased its association with HDL.We suggest that macrophage-derived PAF-AH contains heterogeneous asparagine-conjugated sugar chain(s) involving sialic acid, which hinders its association with HDL but does not influence the secretion, catalytic activity, or resistance of PAF-AH to proteases. |
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| institution | Directory Open Access Journal |
| issn | 0022-2275 |
| language | English |
| last_indexed | 2024-12-16T13:08:42Z |
| publishDate | 2001-10-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Lipid Research |
| spelling | doaj.art-0bbdd01c673d4fc4a3b08d429b895a162022-12-21T22:30:40ZengElsevierJournal of Lipid Research0022-22752001-10-01421016451654N-linked glycosylation of macrophage-derived PAF-AH is a major determinant of enzyme association with plasma HDLAlexandros D. Tselepis0Sonia-Athena P. Karabina1Dominique Stengel2Remi Piédagnel3M. John Chapman4Ewa Ninio5Laboratory of Biochemistry, Department of Chemistry, University of Ioannina, 45110 Ioannina, GreeceLaboratory of Biochemistry, Department of Chemistry, University of Ioannina, 45110 Ioannina, GreeceINSERM U525, IFR 14 Coeur Muscle et Vaisseaux and Faculté de Médecine Pitié-Salpêtrière/Université P. M. Curie Paris 6, Paris, FranceINSERM U489, Hôpital Tenon, Paris, FranceINSERM U551, Hôpital de la Pitié, Paris, FranceINSERM U525, IFR 14 Coeur Muscle et Vaisseaux and Faculté de Médecine Pitié-Salpêtrière/Université P. M. Curie Paris 6, Paris, France; INSERM U525, Faculté de Médecine Pitié-Salpêtrière, 91 Bd de l'Hôpital, Paris Cedex 13 75634 FranceHuman plasma PAF-AH (platelet-activating factor-acetylhydrolase) is a Ca2+-independent phospholipase A2 of hematopoietic origin associated with LDL and HDL; it degrades PAF and oxidizes phospholipids. We show that human macrophages synthesize PAF-AH as a premedial Golgi precursor containing high mannose N-linked glycans. Secreted PAF-AH possesses a molecular mass of ~55 kDa and contains mature N-linked glycans. Secreted PAF-AH activity (90 ± 4% of the total) bound to a wheat germ lectin column and could be eluted with N-acetylglucosamine, whereas digestion with N-acetylneuraminidase II completely abolished enzyme absorption. Tunicamycin significantly reduced cell-associated PAF-AH activity and inhibited enzyme secretion; but it did not alter the ratio of secreted to cell-associated enzyme (1.8 at 6 h and 3.1 at 24 h), suggesting that glycosylation is not essential for PAF-AH secretion. Digestion of cell-associated PAF-AH or secreted PAF-AH with peptide N-glycosidase F affected neither catalytic activity nor its resistance to proteolysis with trypsin or proteinase K; in addition, it did not affect PAF-AH association with LDL, but significantly increased its association with HDL.We suggest that macrophage-derived PAF-AH contains heterogeneous asparagine-conjugated sugar chain(s) involving sialic acid, which hinders its association with HDL but does not influence the secretion, catalytic activity, or resistance of PAF-AH to proteases.http://www.sciencedirect.com/science/article/pii/S0022227520322197atherogenesislipoproteinsmacrophages |
| spellingShingle | Alexandros D. Tselepis Sonia-Athena P. Karabina Dominique Stengel Remi Piédagnel M. John Chapman Ewa Ninio N-linked glycosylation of macrophage-derived PAF-AH is a major determinant of enzyme association with plasma HDL Journal of Lipid Research atherogenesis lipoproteins macrophages |
| title | N-linked glycosylation of macrophage-derived PAF-AH is a major determinant of enzyme association with plasma HDL |
| title_full | N-linked glycosylation of macrophage-derived PAF-AH is a major determinant of enzyme association with plasma HDL |
| title_fullStr | N-linked glycosylation of macrophage-derived PAF-AH is a major determinant of enzyme association with plasma HDL |
| title_full_unstemmed | N-linked glycosylation of macrophage-derived PAF-AH is a major determinant of enzyme association with plasma HDL |
| title_short | N-linked glycosylation of macrophage-derived PAF-AH is a major determinant of enzyme association with plasma HDL |
| title_sort | n linked glycosylation of macrophage derived paf ah is a major determinant of enzyme association with plasma hdl |
| topic | atherogenesis lipoproteins macrophages |
| url | http://www.sciencedirect.com/science/article/pii/S0022227520322197 |
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