Oligodendrocyte-substratum adhesion activates the synthesis of specific lipid species involved in cell signaling
✍ Scribed by Dr. T. Vartanian; S. Szuchet; Dr. Glyn Dawson
- Publisher
- John Wiley and Sons
- Year
- 1992
- Tongue
- English
- Weight
- 952 KB
- Volume
- 32
- Category
- Article
- ISSN
- 0360-4012
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✦ Synopsis
Ovine oligodendrocytes (OLGs) undergo biochemical and morphological changes following attachment to polylysine. Autoradiographs of two-dimensional thin-layer chromatograms of ['4C]Gal-labeled OLG cultures revealed that attachment of OLGs to a polylysine substratum and their subsequent morphological differentiation is accompanied by an increased synthesis of multiple forms of galactosylceramide, sulfogalactosylceramide, and both sulfogalactosyland galactosyl-diglycerides, together with an array of complex sialoglycosphingolipids, predominantly GM, ganglioside. As previously reported, overall lipid synthesis measured by [I4C]acetate incorporation into glycerophosphatides, sphingomyelin, and neutral lipids also increased dramatically for up to 60 days (last time point examined) following OLG-substratum adhesion, reflecting membrane growth. Attachment was associated with a rapid augmentation in the synthesis of ethanolamine plasmalogen from 12 to 27% within 24 hr to reach a 35% plateau at 30 days and remain constant thereafter. In contrast, the plasmalogen content of phosphatidylcholine remained constant at 3 4 % . This rapid increase in lipid synthesis (especially in the ethanolamine plasmalogen content following attachment) closely paralleled increased diacylglycerol (DAG) production and protein kinase C-dependent phosphorylation of both myelin basic protein and 2',3'-cyclic nucleotide phosphohydrolase. Labeling studies indicated that the major source of [3H]arachidonate-labeled DAG following attachment was from phosphatidylinositol turnover (and to a lesser extent phosphatidylcholine) rather than polyphosphoinositides or plasmalogens. Enhanced lipid synthesis is not only required for the production of membranes in these myelin-producing cells but is also a source of second messengers required in the posttranslational modification of key myelin and cellular proteins. o 1992 Wiley-Liss, Inc.