Phosphatidylglucoside Forms Specific Lipid Domains on the Outer Leaflet of the Plasma Membrane

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• 作者：Motohide Murate ; Tomohiro Hayakawa ; Kumiko Ishii ; Hironori Inadome ; Peter Greimel ; Masaki Watanabe ; Yasuko Nagatsuka ; Kazuki Ito ; Yukishige Ito ; Hiroshi Takahashi ; Yoshio Hirabayashi ; Toshihide Kobayas
• 刊名：Biochemistry
• 出版年：2010
• 出版时间：June 15, 2010
• 年：2010
• 卷：49
• 期：23
• 页码：4732-4739
• 全文大小：897K
• 年卷期：v.49,no.23(June 15, 2010)
• ISSN：1520-4995

文摘

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.