title: Human sphingosine kinase: molecular cloning, functional characterization and tissue distribution.
abstract: Sphingosine-1-phosphate (SPP), the product of sphingosine kinase, is an important signaling molecule with intra- and extracellular functions. The cDNA for the mouse sphingosine kinase has recently been reported. In this paper we describe the cloning, expression and characterization of the human sphingosine kinase (huSPHK1). Sequence analysis comparison revealed that this kinase is evolutionarily very conserved, having a high degree of homology with the murine enzyme, and presenting several conserved regions with bacteria, yeast, plant, and mammalian proteins. Expressed huSPHK1 cDNA specifically phosphorylates D-erythro-sphingosine and, to a lesser extent, D, L-erythro-dihydrosphingosine, and not at all the 'threo' isoforms of dihydrosphingosine; hydroxy-ceramide or non-hydroxy-ceramide; diacylglycerol (DAG); phosphatidylinositol (PI); phosphatidylinositol-4-phosphate (PIP); or phosphatidylinositol-4, 5-bisphosphate (PIP(2)). huSPHK1 shows typical Michaelis-Menten kinetics (V(max)=56microM and K(m)=5microM). The kinase is inhibited by D,L-threo-dihydrosphingosine (K(i)=3microM), and by N, N-dimethyl-sphingosine (K(i)=5microM). Northern blots indicate highest expression in adult lung and spleen, followed by peripheral blood leukocyte, thymus and kidney, respectively. It is also expressed in brain and heart. In addition, database searches with the stSG2854 sequence indicate that huSPHK1 is also expressed in endothelial cells, retinal pigment epithelium, and senescent fibroblasts.
authors.affiliation: Department of Molecular and Cellular Biology, Institut de Recherche Jouveinal/Parke-Davis, Fresnes, France. alirio.melendez@wl.com
authors.forename: A J
authors.initials: AJ
authors.lastname: Melendez
authors.forename: E
authors.initials: E
authors.lastname: Carlos-Dias
authors.forename: M
authors.initials: M
authors.lastname: Gosink
authors.forename: J M
authors.initials: JM
authors.lastname: Allen
authors.forename: L
authors.initials: L
authors.lastname: Takacs
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D019556:COS Cells; D002874:Chromosome Mapping; D002886:Chromosomes, Human, Pair 17 / Q000235:genetics; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D004274:DNA, Recombinant / Q000235:genetics; D019143:Evolution, Molecular; D005260:Female; D005822:Genetic Vectors; D006801:Humans; D007700:Kinetics; D008969:Molecular Sequence Data; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity; D014018:Tissue Distribution; D014162:Transfection; D000099157:Sphingosine Kinase
chemical_list: D018076:DNA, Complementary; D004274:DNA, Recombinant; D017853:Phosphotransferases (Alcohol Group Acceptor); D012333:RNA, Messenger; D000099157:Sphingosine Kinase