Lyso-glycosphingolipids mobilize calcium from brain microsomes via multiple mechanisms

Lloyd-Evans, Emyr ORCID: https://orcid.org/0000-0002-3626-1611, Pelled, Dori, Riebeling, Christian and Futerman, Anthony H. 2003. Lyso-glycosphingolipids mobilize calcium from brain microsomes via multiple mechanisms. Biochemical Journal 375 (3) , pp. 561-565. 10.1042/BJ20030613

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Abstract

Recently, we demonstrated that the GSL (glycosphingolipid), GlcCer (glucosylceramide), modulates Ca2+ release from intracellular stores and from microsomes by sensitizing the RyaR (ryanodine receptor), a major Ca2+-release channel of the endoplasmic reticulum, whereas the lyso derivative of GlcCer, namely GlcSph (glucosylsphingosine), induced Ca2+ release via a mechanism independent of the RyaR [Lloyd-Evans, Pelled, Riebeling, Bodennec, de-Morgan, Waller, Schiffmann and Futerman (2003) J. Biol. Chem. 278, 23594–23599]. We now systematically examine the mechanism by which GlcSph and other lyso-GSLs modulate Ca2+ mobilization from rat brain cortical and cerebellar microsomes. GlcSph, lactosylsphingosine and galactosylsphingosine all mobilized Ca2+, but at significantly higher concentrations than those required for GlcCer-mediated sensitization of the RyaR. GlcSph-induced Ca2+ mobilization was partially blocked by heparin, an inhibitor of the Ins(1,4,5)P3 receptor, and also partially blocked by thapsigargin or ADP, inhibitors of SERCA (sarcoplasmic/endoplasmic reticulum Ca2+-ATPase), but completely blocked when both acted together. In contrast, neither lactosylsphingosine nor galactosylsphingosine had any effect on Ca2+ release via either the Ins(1,4,5)P3 receptor or SERCA, but acted as agonists of the RyaR. Finally, and surprisingly, all three lyso-GSLs reversed inhibition of SERCA by thapsigargin. We conclude that different lyso-GSLs modulate Ca2+ mobilization via different mechanisms, and discuss the relevance of these findings to the GSL storage diseases in which lyso-GSLs accumulate.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Biosciences
Subjects:	Q Science > Q Science (General)
Uncontrolled Keywords:	Galactosylsphingosine, glucosylsphingosine, Ins(1,4,5)P3, lactosylsphingosine, ryanodine, thapsigargin.
Publisher:	Biochemical Society
ISSN:	0264-6021
Last Modified:	27 Oct 2022 08:48
URI:	https://orca.cardiff.ac.uk/id/eprint/63433

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