Ligation of sphingosine 1-phosphate (S1P) to a set of specific receptors named S I P receptors (S1PRs) regulates important biological processes. Although the ability of S I P to increase cytosolic Ca2+ in various cell types is well known, the role of the individual S1PRs has not been fully characterized. Here, we provide a complete analysis of SIP-dependent intracellular Ca2+ homeostasis in HeLa cells. Overexpression Of S1P(2), or S1P(3), but not S1P(1), leads to a significant increase in cytosolic and mitochondrial [Ca2+] in response to S I P challenge. Moreover, cells ectopically expressing S1P(2), or S1P(3) exhibited an appreciable decrease of the free Ca2+ concentration in the endoplasmic reticulum, dependent on stimulation of receptors by S I P endogenously present in the culture medium which was accompanied by a reduced susceptibility to C-2-ceramide-induced cell death. These results demonstrate a differential contribution of individual S1PRs to Ca2+ homeostasis and its possible implication in the regulation of cell survival. (c) 2006 Elsevier Inc. All rights reserved.