title: Bis (monoacylglycero) phosphate interfacial properties and lipolysis by pancreatic lipase-related protein 2, an enzyme present in THP-1 human monocytes.
abstract: The interfacial physical properties of bis(monoacylglycero)phosphate (BMP) and its derivatives with three oleoyl chains (hemi-BDP) and four oleoyl chains (bis(diacylglycero)phosphate, BDP) were investigated using Langmuir monomolecular films. The mean molecular area of BMP at the collapse surface pressure (45mN m(-1)) was similar to those measured with other phospholipids bearing two acyl chains (66 and 59.6Å(2) molecule(-1) at pH 5.5 and 8.0, respectively). In Hemi-BDP and BDP, the mean molecular area increased by 26 and 35Å(2) molecule(-1) per additional acyl chain at pH 5.5 and 8.0, respectively. When BMP was added to a phospholipid mixture mimicking late endosome membrane composition at pH 8.0, the mean phospholipid molecular area increased by 7% regardless of the surface pressure. In contrast, the variation in molecular area was surface pressure-dependent at pH 5.5, a pH value close to that of intra-endosomal content. BMP and hemi-BDP, but not BDP, were hydrolyzed by pancreatic lipase-related protein 2 (PLRP2), which exhibits phospholipase A(1) activity. At pH 5.5, the maximum activities of PLRP2 on BMP were recorded at high surface pressures (25-35mN/m). At pH 8.0, the PLRP2 activity vs. surface pressure showed a bell-shaped curve with maximum activities at 15mN/m for both BMP and hemi-BDP. This is a new activity for this enzyme which could degrade cellular BMP since both human PLRP2 (HPLRP2) and BMP were localized in human monocytic THP-1 cells. This is the first report on the cellular localization of HPLRP2 in human monocytes.
authors.affiliation: Cancer Research Center of Toulouse, Université Toulouse 3, France. michel.record@inserm.fr
authors.forename: Michel
authors.initials: M
authors.lastname: Record
authors.forename: Sawsan
authors.initials: S
authors.lastname: Amara
authors.forename: Caroline
authors.initials: C
authors.lastname: Subra
authors.forename: Guowei
authors.initials: G
authors.lastname: Jiang
authors.forename: Glenn D
authors.initials: GD
authors.lastname: Prestwich
authors.forename: Francine
authors.initials: F
authors.lastname: Ferrato
authors.forename: Frédéric
authors.initials: F
authors.lastname: Carrière
mesh_terms: D001483:Base Sequence; D055592:Biophysical Phenomena; D002460:Cell Line; D018076:DNA, Complementary / Q000235:genetics; D011992:Endosomes / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007150:Immunohistochemistry; D008049:Lipase / Q000235:genetics / Q000378:metabolism*; D008066:Lipolysis; D008246:Lysophospholipids / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology*; D015394:Molecular Structure; D009000:Monocytes / Q000187:drug effects / Q000378:metabolism; D050178:Monoglycerides / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology*; D010712:Phosphatidic Acids / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D053835:Unilamellar Liposomes / Q000737:chemistry
chemical_list: D018076:DNA, Complementary; D008246:Lysophospholipids; D050178:Monoglycerides; D010712:Phosphatidic Acids; D011994:Recombinant Proteins; D053835:Unilamellar Liposomes; C012786:bis(monoacylglyceryl)phosphate; D008049:Lipase; C075988:pancreatic lipase related protein 2