title: Sphingosine 1-phosphate-induced cell rounding and neurite retraction are mediated by the G protein-coupled receptor H218.
abstract: Sphingosine 1-phosphate (SPP) is a lipid second messenger that also acts as a first messenger through the G protein-coupled receptor Edg-1. Here we show that SPP also binds to the related receptors H218 and Edg-3 with high affinity and specificity. SPP and sphinganine 1-phosphate bind to these receptors, whereas neither sphingosylphosphorylcholine nor lysophosphatidic acid compete with SPP for binding to either receptor. Transfection of HEK293 cells with H218 or edg-3, but not edg-1, induces rounded cell morphology in the presence of serum, which contains high levels of SPP. SPP treatment of cells overexpressing H218 cultured in delipidated serum causes cell rounding. A similar but less dramatic effect was observed in cells overexpressing Edg-3 but not with Edg-1. Cell rounding was correlated with apoptotic cell death, probably as a result of loss of attachment. Nerve growth factor-induced neuritogenesis in PC12 cells was inhibited by overexpression of H218 and to a lesser extent Edg-3. SPP treatment rapidly enhanced neurite retraction in PC12 cells overexpressing Edg-1, Edg-3, or H218. Thus, H218, and possibly Edg-3, may be the cell surface receptors responsible for cell rounding and neurite retraction induced by SPP. Moreover, the identification of these two additional SPP receptors indicates that a family of highly specific receptors exists that mediate different responses to SPP.
authors.affiliation: Department of Biochemistry and Molecular Biology, Georgetown University Medical Center, Washington, D.C. 20007, USA.
authors.forename: J R
authors.initials: JR
authors.lastname: Van Brocklyn
authors.forename: Z
authors.initials: Z
authors.lastname: Tu
authors.forename: L C
authors.initials: LC
authors.lastname: Edsall
authors.forename: R R
authors.initials: RR
authors.lastname: Schmidt
authors.forename: S
authors.initials: S
authors.lastname: Spiegel
mesh_terms: D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D017931:DNA Primers; D019204:GTP-Binding Proteins / Q000378:metabolism*; D006801:Humans; D017874:Immediate-Early Proteins / Q000378:metabolism; D008246:Lysophospholipids; D016716:PC12 Cells; D011485:Protein Binding; D051381:Rats; D011956:Receptors, Cell Surface / Q000378:metabolism*; D043562:Receptors, G-Protein-Coupled; D049312:Receptors, Lysophospholipid; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000378:metabolism