Phosphatidylglucoside Forms Specific Lipid Domains on the Outer Leaflet of the Plasma Membrane
Phosphatidylglucoside Forms Specific Lipid Domains on the Outer Leaflet of the Plasma Membrane
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DOI：
10.1021/bi100007u
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发表时间：
2010-06-15
期刊：
影响因子：
2.9
通讯作者：
Kobayashi, Toshihide
中科院分区：
文献类型：
--
作者：
Murate, Motohide;Hayakawa, Tomohiro;Kobayashi, Toshihide
磷脂酰葡萄糖苷（PtdGlc）是近年来发现的一种独特的糖磷脂，参与人早幼粒细胞白血病细胞系HL 60的粒细胞分化和发育中啮齿类动物脑星形胶质细胞的分化。使用PtdGlc特异性单克隆抗体在免疫荧光和免疫电子显微镜，我们发现，PtdGlc形成不同的脂质结构域的HL 60细胞和人肺泡上皮细胞系A549的质膜的外叶。类似于鞘糖脂，葡萄糖神经酰胺（GlcCer），天然形式的PtdGlc在差示扫描量热法（DSC）中表现出高的主相变温度。然而，与GlcCer不同，PtdGlc在加热和冷却扫描之间的主相变温度中没有表现出大的差异。DSC进一步表明GlcCer而不是PtdGlc与鞘磷脂混溶。此外，DSC和小角X-射线散射（SAXS）实验表明，PtdGlc与磷脂酰胆碱混溶性差。我们的研究结果表明，缺乏紧密的分子间相互作用排除PtdGlc从质膜上的其他脂质结构域。
Phosphatidylglucoside (PtdGlc) is a recently discovered unique glycophospholipid involved in granulocytic differentiation of human promyelocytic leukemia cell line HL60 and in astrocytic differentiation in developing rodent brains. Using a PtdGlc-specific monoclonal antibody in immunofluorescence and immunoelectron microscopy, we showed that PtdGlc forms distinct lipid domains on the outer leaflet of the plasma membrane of HL60 cells and the human alveolar epithelial cell line, A549. Similar to glycosphingolipid, glucosylceramide (GlcCer), the natural form of PtdGlc exhibited a high main phase transition temperature in differential scanning calorimetry (DSC). However, unlike GlcCer, PtdGlc did not exhibit a large difference in the main phase transition temperature between the heating and cooling scans. DSC further indicated that GlcCer, but not PtdGlc, was miscible with sphingomyelin. In addition, DSC and small-angle X-ray scattering (SAXS) experiments revealed that PtdGlc was poorly miscible with phosphatidylcholine. Our results suggest that the lack of tight intermolecular interaction excludes PtdGlc from other lipid domains on the plasma membrane.