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Discrimination between plasma membrane and intracellular target sites of sphingosylphosphorylcholine.

Authors :
Meyer zu Heringdorf D
Niederdräing N
Neumann E
Fröde R
Lass H
Van Koppen CJ
Jakobs KH
Source :
European journal of pharmacology [Eur J Pharmacol] 1998 Jul 31; Vol. 354 (1), pp. 113-22.
Publication Year :
1998

Abstract

On the background of the emerging concept of G protein-coupled sphingolipid receptors, Ca2+ mobilization by sphingosylphosphorylcholine (SPPC) in intact cells and SPPC-induced Ca2+ release in permeabilized cells, both occurring at similar, micromolar concentrations, were characterized and compared. In intact human embryonic kidney (HEK-293) cells, SPPC rapidly increased [Ca2+]i by mobilization of Ca2+ from thapsigargin-sensitive stores. In saponin-permeabilized HEK-293 cells, SPPC released stored Ca2+, in a manner similar to but independent of inositol 1,4,5-trisphosphate. Only the action of SPPC on intact cells, but not that in permeabilized cells, was, at least in part, sensitive to pertussis toxin. In addition and most important, Ca2+ release by SPPC in permeabilized cells was not stereoselective, whereas in intact cells only the naturally occurring D-erythro-SPPC, but not L-threo-SPPC, increased [Ca2+]i. Stereoselectivity of SPPC-induced [Ca2+]i increase was also demonstrated in bovine aortic endothelial cells. In conclusion, Ca2+ mobilization by SPPC in intact cells is independent of the previously described SPPC-gated Ca2+ channel on endoplasmic reticulum but probably mediated by a membrane sphingolipid receptor. Thus, SPPC can regulate Ca2+ homeostasis by acting apparently at two cellular targets, which exhibit clearly distinct recognition patterns.

Details

Language :
English
ISSN :
0014-2999
Volume :
354
Issue :
1
Database :
MEDLINE
Journal :
European journal of pharmacology
Publication Type :
Academic Journal
Accession number :
9726638
Full Text :
https://doi.org/10.1016/s0014-2999(98)00436-1