Human sphingosine-1-phosphate lyase: cDNA cloning, functional expression studies and mapping to chromosome 10q22(1).
Sphingosine-1-phosphate lyase catalyzes the last step in sphingolipid breakdown, the cleavage of phosphorylated sphingoid bases such as sphingenine-1-phosphate. The latter lipid is not only a catabolite, but can influence as an inter- and/or intracellular second messenger many cellular processes. To allow for the diagnosis of human disorders that might be linked to a deficient lyase, the human sphingosine-1-phosphate lyase cDNA was cloned. The obtained cDNA encoded a protein of 568 amino acids with a calculated molecular mass of 63492 Da. Hydropathy plots revealed the presence of one membrane span near the amino-terminal which is however not required for enzyme activity since recombinant poly-His-tagged lyase, lacking this membrane span, was functionally active. Site-directed mutagenesis disclosed the importance of the cysteine residues 218 and 317 for the cleavage reaction. Northern analysis showed the presence of rare large-sized mRNAs of 6.7, 5.8 and 4 kb and the highest expression in liver. By fluorescent in situ hybridization, the gene was mapped to chromosome 10q22.
Van Veldhoven
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PP
Katholoeke Universiteit Leuven, Departement Moleculaire Celbiologie, Leuven, Belgium. paul.vanveldhoven@med.kuleuven.ac.be
Gijsbers
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S
Mannaerts
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GP
Vermeesch
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JR
Brys
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D000446:Aldehyde-Lyases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D000595:Amino Acid Sequence; D001483:Base Sequence; D015152:Blotting, Northern; D002874:Chromosome Mapping; D002879:Chromosomes, Human, Pair 10; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry; D015870:Gene Expression; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008969:Molecular Sequence Data; D016415:Sequence Alignment
D018076:DNA, Complementary; D000446:Aldehyde-Lyases; C022649:sphingosine 1-phosphate lyase (aldolase)