Premium
Fluorescent analogues of plasma membrane sphingolipids are sorted to different intracellular compartments in astrocytes
Author(s) -
Tomás Mónica,
Durán Juan M,
Lázaro-Diéguez Francisco,
Babià Teresa,
Renau-Piqueras Jaime,
Egea Gustavo
Publication year - 2004
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(04)00245-5
Subject(s) - sphingolipid , endocytic cycle , endosome , sphingomyelin , microbiology and biotechnology , endocytosis , ceramide , intracellular , internalization , golgi apparatus , biology , chemistry , biochemistry , membrane , cell , endoplasmic reticulum , apoptosis
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 C 6 ‐NBD‐glucosylceramide (NBD‐GlcCer) and C 6 ‐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.