Fluorescent analogues of plasma membrane sphingolipids are sorted to different intracellular compartments in astrocytes

FEBS Letters

Renau-Piqueras, Jaime¹  Babià, Teresa²  Durán, Juan M²  Egea, Gustavo²  Lázaro-Diéguez, Francisco²  Tomás, Mónica² 

[1] Centro de Investigación, Hospital La Fe, E-46009 Valencia, Spain;Departament de Biologia Cel.lular i Anatomia Patològica, Facultat de Medicina, Universitat de Barcelona-IDIBAPS, C/ Casanova 143, E-08036 Barcelona, Spain

关键词: NBD-lipid;    Glial cell;    Alcohol;    Endocytosis;    Golgi apparatus;    Endosome;   

DOI  :  10.1016/S0014-5793(04)00245-5

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Sphingolipids are basic constituents of cellular membranes and are essential for numerous functions such as intracellular signalling. They are transported along the exocytic and endocytic pathways in eukaryotic cells. After endocytosis, fluorescent-labelled sphingolipids are sorted to distinct intracellular organelles prior to recycling (via early/recycling endosomes) or degradation (late endosomes/lysosomes). Here we examine, in primary cultures of rat astrocytes, the internalisation routes followed by C₆-NBD-glucosylceramide (NBD-GlcCer) and C₆-NBD-sphingomyelin (NBD-SM) and the effects of ethanol on their endocytic trafficking. Endocytosed plasma membrane NBD-GlcCer and NBD-SM are diverted to the Golgi apparatus and lysosomes, respectively. These different internalisation pathways are maintained regardless of the differentiation stage of astrocytes. Chronic ethanol exposure did not alter this endocytic sorting, but delayed the internalisation of both NBD-sphingolipids. Moreover, ethanol also stimulated the in situ metabolism of NBD-ceramide to NBD-GlcCer and NBD-SM. We conclude that in rat astrocytes internalised plasma membrane NBD-sphingolipids are sorted to different subcellular compartments. The exposure to chronic ethanol perturbed the lipid endocytic process and stimulated the de novo synthesis of NBD-sphingolipids, shifting the balance of sphingolipid metabolism in favour of the sphingomyelin pathway.

【 授权许可】

Unknown