Sphingolipid receptors

Intracellular, ER-located, ligand-gated Ca2+ channels include the inositol-1,4,5-triphosphate (IP3) receptor, the ryanodine receptor (RyR), the NAADP receptor and the sphingolipid receptor [157-159]. The IP3 receptor Ca2+ channel is opened by IP3 generated as a result of G protein-(or RTK)-mediated PLC activation [159]. 

NAADP receptor Ca2+ channels are opened by very low NAADP concentrations but is blocked at higher NAADP concentrations [157]. Sphingolipid receptor Ca2+ channels may be opened by sphingosine-1-phosphate or sphingosyl-phosphorylcholine [157]. 

NH3)3Ru-0-Ru(NH3) -0-Ru(NH3) )]C1( ) (metal coordination complex) Sphingolipid-gated Ca2+ channel (Sphingolipid receptor) (SPH-R) [Psychosine (= D-Galactosyl- Widespread lipid mediator in 4.4F Inactive as SPFI-R ligand... 

While the fluid mosaic model of membrane stmcture has stood up well to detailed scrutiny, additional features of membrane structure and function are constantly emerging. Two structures of particular current interest, located in surface membranes, are tipid rafts and caveolae. The former are dynamic areas of the exo-plasmic leaflet of the lipid bilayer enriched in cholesterol and sphingolipids they are involved in signal transduction and possibly other processes. Caveolae may derive from lipid rafts. Many if not all of them contain the protein caveolin-1, which may be involved in their formation from rafts. Caveolae are observable by electron microscopy as flask-shaped indentations of the cell membrane. Proteins detected in caveolae include various components of the signal-transduction system (eg, the insutin receptor and some G proteins), the folate receptor, and endothetial nitric oxide synthase (eNOS). Caveolae and lipid rafts are active areas of research, and ideas concerning them and their possible roles in various diseases are rapidly evolving. 

Lehtonen, J.Y.A., Horiuchi, M., Daviet, L., AMshita, M. and Dzau, V.J., 1999, Activation of the de novo biosynthesis of sphingolipids mediates angiotensin 11 type 2 receptor-induced apoptosis. J. Biol. Chem. 274 16901-16906. 

Glycosphingolipids Function as Structural Components and as Specific Cell Receptors Defects in Sphingolipid Catabolism Are Associated with Metabolic Diseases... 

EDG1 Endothelial differentiation, sphingolipid G-protein-coupled receptor... 

Stevens, V. L. and Tang, J. (1997). Fumonisin Bl-induced sphingolipid depletion inhibits vitamin uptake via the glycosylphosphatidylinositol-anchored folate receptor. ]. Biol. Chem. 272(29), 18020-18025. 

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