Repair of BHK cell surface ganglioside GM3 after its degradation by extracellular sialidase

Citation
Dj. Sillence et D. Allan, Repair of BHK cell surface ganglioside GM3 after its degradation by extracellular sialidase, MOL MEMBR B, 15(4), 1998, pp. 229-235
Citations number
49
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Cell & Developmental Biology
Journal title
MOLECULAR MEMBRANE BIOLOGY
ISSN journal
0968-7688 → ACNP
Volume
15
Issue
4
Year of publication
1998
Pages
229 - 235
Database
ISI
SICI code
0968-7688(199810/12)15:4<229:ROBCSG>2.0.ZU;2-1
Abstract
Treatment of BHK fibroblasts with V, cholerae sialidase for 20 min caused t he breakdown of about 70% of total cellular ganglioside GM3 and the product ion of an approximately equivalent amount of lactosylceramide. On removal o f the enzyme, a slow resynthesis of GM3 from lactosylceramide was observed, equivalent to about 5-6%/h of the degraded GM3. Resynthesis of degraded su rface ganglioside has not previously been observed, but its magnitude is si milar to previous measurements of the rate of protein resialylation after s ialidase treatment. This suggests that resialylation of both lipid and prot ein is limited by vesicular transport of plasma membrane components through the trans-Golgi network [TGN] where sialyltransferase is thought to be loc alized. In contrast, resynthesis of sphingomyelin which has been degraded a t the cell surface by exogenous sphingomyelinase is about five times faster than resynthesis of GM3 and may involve non-vesicular transport of ceramid e.