Molecular features of phospholipids that affect glycolipid transfer protein-mediated galactosylceramide transfer between vesicles |
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Authors: | Matts Nylund Julian G Molotkovsky Robert Bittman |
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Institution: | a Department of Biochemistry and Pharmacy, Åbo Akademi University, Turku, Finland b The Shemyakin-Ovchinnikov Institute for Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia c Department of Chemistry and Biochemistry, Queens College of The City University of New York, Flushing, NY 11367, USA |
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Abstract: | The glycolipid transfer protein (GLTP)-mediated movement of galactosylceramide from model membrane donor vesicles to acceptor vesicles is sensitive to the membrane environment surrounding the glycolipid. GLTP can catalyze the transfer of a fluorescently labeled GSL, anthrylvinyl-galactosylceramide (AV-GalCer), from vesicles composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine and dipalmitoylphosphatidylcholine matrices, but not from vesicles prepared from N-palmitoylsphingomyelin, regardless of the cholesterol content of the vesicles. In this study, we have examined the structural features of sphingomyelin (SM) that are responsible for its inhibition of the rate of GLTP-catalyzed transfer of AV-GalCer. The rate of glycolipid transfer was enhanced when the N-palmitoyl chain of SM was replaced with an N-oleoyl chain. Analogs of N-palmitoyl-SM in which the 4,5-double bond of the long-chain base is reduced or the 3-hydroxy group is removed did not inhibit GLTP-catalyzed transfer of AV-GalCer. When the donor vesicles were prepared with phosphatidylcholines or ether-linked phosphatidylcholine analogs, the transfer rates of AV-GalCer increased with increasing degree of unsaturation. The rate of AV-GalCer transfer was strongly dependent on the unsaturation degree of the acyl and/or alkyl chains. For ester-linked PCs, the transfer rate increased in the order DPPC < POPC < DOPC, which have 0, 1, and 2 cis double bonds, respectively. |
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Keywords: | SUV small unilamellar vesicles GLTP glycolipid transfer protein GSL glycosphingolipids PSM d-erythro-sphingosylphosphorylcholine" target="_blank">N-palmitoyl-d-erythro-sphingosylphosphorylcholine PDHSM d-erythro-dihydrosphingosylphosphorylcholine" target="_blank">N-palmitoyl-d-erythro-dihydrosphingosylphosphorylcholine OSM d-erythro-sphingosylphosphorylcholine" target="_blank">N-oleoyl-d-erythro-sphingosylphosphorylcholine ODHSM d-erythro-dihydrosphingosylphosphorylcholine" target="_blank">N-oleoyl-d-erythro-dihydrosphingosylphosphorylcholine 3-deoxy-PSM 3-deoxy-N-palmitoylsphingosylphosphorylcholine POPC 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine DPPC 1 2-dipalmitoyl-sn-glycero-3-phosphocholine DOPC 1 2-dioleoyl-sn-glycero-3-phosphocholine HPPC 1-O-hexadecyl-2-(deoxy-N-palmitoylamido)-sn-glycero-3-phosphocholine DHPC 1 2-di-O-hexadecyl-sn-glycero-3-phosphocholine di-oleyl-PC 1 2-di-O-octadec-9(Z)-enyl-sn-glycero-3-phosphocholine HOPC 1-O-hexadecyl-2-oleoyl-sn-glycero-3-phosphocholine AV-GalCer N-[(11E)-12-(9-anthroyl)-11-dodecenoyl]-1-O-β-galactosylsphingosine DiOC16 3 3&prime -dihexadecyloxacarbocyanine perchlorate |
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