title: Identification and characterization of Saccharomyces cerevisiae dihydrosphingosine-1-phosphate phosphatase.
abstract: We have identified the yeast sphingosine resistance gene (YSR2) of Saccharomyces cerevisiae as encoding a protein that specifically dephosphorylates dihydrosphingosine 1-phosphate (DHS-1-P), and we refer to this protein as dihydrosphingosine-1-phosphate phosphatase. Overexpression of YSR2 conferred sphingosine resistance to the dihydrosphingosine-1-P lyase-defective mutant (JS16) of S. cerevisiae, which is hypersensitive to sphingosine. The ysr2Delta deletion mutant of S. cerevisiae accumulated DHS-1-P compared with its wild type strain upon labeling with D-erythro-[4, 5-3H]dihydrosphingosine, whereas overexpression of YSR2 increased dephosphorylation of DHS-1-P. An epitope-tagged fusion protein (YSR2-Flag) was partially purified and found to specifically dephosphorylate DHS-1-P to yield dihydrosphingosine. YSR2 failed to dephosphorylate ceramide 1-phosphate or phosphatidic acid. Functionally, the mutant bearing the ysr2Delta deletion decreased labeling of sphingolipids and increased labeling of glycerolipids dramatically following in vivo labeling with D-erythro-[3H]dihydrosphingosine, but it slightly affected labeling of sphingolipids with inositol. Taken together, these results identify YSR2 as dihydrosphingosine-1-phosphate phosphatase. They also raise the intriguing possibility that phosphorylation followed by dephosphorylation is required for incorporation of exogenous long chain sphingoid bases into sphingolipids.
authors.affiliation: Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710, USA.
authors.forename: C
authors.initials: C
authors.lastname: Mao
authors.forename: M
authors.initials: M
authors.lastname: Wadleigh
authors.forename: G M
authors.initials: GM
authors.lastname: Jenkins
authors.forename: Y A
authors.initials: YA
authors.lastname: Hannun
authors.forename: L M
authors.initials: LM
authors.lastname: Obeid
mesh_terms: D004352:Drug Resistance, Microbial / Q000235:genetics; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism; D016366:Open Reading Frames; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics; D017384:Sequence Deletion; D013107:Sphingolipids / Q000378:metabolism; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000378:metabolism
chemical_list: D008565:Membrane Proteins; D013107:Sphingolipids; C060504:dihydrosphingosine 1-phosphate; D013110:Sphingosine