Syringomycin Action Gene SYR2 Is Essential for Sphingolipid 4-Hydroxylation in Saccharomyces cerevisiae

Grilley, Michelle; Stock, Stephen D.; Dickson, Robert C.; Lester, Robert L.; Takemoto, Jon Y.

doi:10.1074/jbc.273.18.11062

Cited by 143 publications

(129 citation statements)

References 53 publications

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“…To answer this question, we used a mutant strain that is defective in the conversion of DHS to PHS. In previous studies (27,28), the syr2 mutant strain was shown to be defective in the C-4 hydroxylation of DHS and dihydroceramide to PHS and PHC, respectively, and the SYR2 gene was proposed to encode a lipid hydroxylase. Therefore, we first determined whether the syr2⌬ mutant strain shows defects in the conversion of DHS to PHS in the JK9-3d strain background.…”

Section: Dhs Needs To Be Converted To Phs To Inhibit Growth-tomentioning

confidence: 99%

Phytosphingosine as a Specific Inhibitor of Growth and Nutrient Import in Saccharomyces cerevisiae

Chung¹,

Mao²,

Heitman³

et al. 2001

Journal of Biological Chemistry

110

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In this study, we used a combination of pharmacological and genetic approaches to determine which endogenous sphingolipid is the likely mediator of growth inhibition. When cells were treated with exogenous phytosphingosine (PHS, 20 M) or structurally similar or metabolically related molecules, including 3-ketodihydrosphingosine, dihydrosphingosine, C 2 -phytoceramide (PHC), and stearylamine, only PHS inhibited growth. Also, PHS was shown to inhibit uptake of uracil, tryptophan, leucine, and histidine. Again this effect was specific to PHS. Because of the dynamic nature of sphingolipid metabolism, however, it was difficult to conclude that growth inhibition was caused by PHS itself. By using mutant yeast strains defective in various steps in sphingolipid metabolism, we further determined the specificity of PHS. The elo2⌬ strain, which is defective in the conversion of PHS to PHC, was shown to have slower biosynthesis of ceramides and to be hypersensitive to PHS (5 M), suggesting that PHS does not need to be converted to PHC. The lcb4⌬ lcb5⌬ strain is defective in the conversion of PHS to PHS 1-phosphate, and it was as sensitive to PHS as the wild-type strain. The syr2⌬ mutant strain was defective in the conversion of DHS to PHS. Interestingly, this strain was resistant to high concentrations of DHS (40 M) that inhibited the growth of an isogenic wild-type strain, demonstrating that DHS needs to be converted to PHS to inhibit growth. Together, these data demonstrate that the active sphingolipid species that inhibits yeast growth is PHS or a closely related and yet unidentified metabolite.Certain sphingolipid metabolites including ceramide, sphingosine, and sphingosine 1-phosphate have pleiotropic effects on cellular growth and proliferation. The yeast Saccharomyces cerevisiae has emerged as an excellent model system for studying sphingolipid-mediated signal transduction. First, compared with over 300 different kinds of sphingolipids found in mammalian cells, there is only a limited number of sphingolipid species in the yeast, which simplifies lipid analysis (2, 3). Moreover, the basic structure, biosynthesis, and metabolism of sphingolipids are well conserved between mammalian and yeast systems. Second, many yeast genes in the sphingolipid biosynthetic and metabolic pathways have been cloned, providing opportunities for studying the effects of endogenous sphingolipids using genetics tools. Finally, although this is not exclusive to sphingolipid studies, yeast genetics provide excellent tools to identify and characterize components in signal transduction pathways (4 -6).Evidence for conservation of the sphingolipid signaling pathway in yeast comes from several studies. These include demonstrating that D-erythro-ceramide inhibited yeast cell growth in liquid culture and activated a protein phosphatase 2A that could be inhibited by okadaic acid (7). Later, Nickels and Broach (8) showed that ceramide inhibited yeast cell growth by arresting cell cycle at G 1 phase and that ceramide-activated protein phosphatase is com...

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Section: Dhs Needs To Be Converted To Phs To Inhibit Growth-tomentioning

confidence: 99%

Phytosphingosine as a Specific Inhibitor of Growth and Nutrient Import in Saccharomyces cerevisiae

Chung¹,

Mao²,

Heitman³

et al. 2001

Journal of Biological Chemistry

110

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“…Serine palmitoyltransferase (SPT) catalyzes the decarboxylative condensation of serine with palmitoyl CoA to form 3-KS in the first step of the long-chain-base synthesis pathway. 3-KS is reduced to DHS by Tsc10p (22) and DHS is hydroxylated to PHS by Sur2p (28,29). Addition of 3-KS, DHS, or PHS to the growth medium rescues the lethality of lcb1⌬ or lcb2⌬ mutant cells.…”

Section: Mutations In the Predicted Plp-binding Residues Of Lcb2pmentioning

confidence: 99%

Mutations in the Yeast LCB1 and LCB2Genes, Including Those Corresponding to the Hereditary Sensory Neuropathy Type I Mutations, Dominantly Inactivate Serine Palmitoyltransferase

Gable¹,

Han²,

Monaghan³

et al. 2002

Journal of Biological Chemistry

104

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It was recently demonstrated that mutations in the human SPTLC1 gene, encoding the Lcb1p subunit of serine palmitoyltransferase (SPT), cause hereditary sensory neuropathy type I (1, 2). As a member of the subfamily of pyridoxal 5-phosphate enzymes known as the ␣-oxoamine synthases, serine palmitoyltransferase catalyzes the committed step of sphingolipid synthesis. The residues that are mutated to cause hereditary sensory neuropathy type I reside in a highly conserved region of Lcb1p that is predicted to be a catalytic domain of Lcb1p on the basis of alignments with other members of the ␣-oxoamine synthase family. We found that the corresponding mutations in the LCB1 gene of Saccharomyces cerevisiae reduce serine palmitoyltransferase activity. These mutations are dominant and decrease serine palmitoyltransferase activity by 50% when the wild-type and mutant LCB1 alleles are coexpressed. We also show that serine palmitoyltransferase is an Lcb1p⅐Lcb2p heterodimer and that the mutated Lcb1p proteins retain their ability to interact with Lcb2p. Modeling studies suggest that serine palmitoyltransferase is likely to have a single active site that lies at the Lcb1p⅐Lcb2p interface and that the mutations in Lcb1p reside near the lysine in Lcb2p that is expected to form the Schiff's base with the pyridoxal 5-phosphate cofactor. Furthermore, mutations in this lysine and in a histidine residue that is also predicted to be important for pyridoxal 5-phosphate binding to Lcb2p also dominantly inactivate SPT similar to the hereditary sensory neuropathy type 1-like mutations in Lcb1p.

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“…Although these biosynthetic steps are common to GlcCer and IPC pathways, these two components are produced by two distinct ceramide synthases in yeast and filamentous fungi [23,26,36,37], suggesting that these two enzymes possess different substrate specificities. During IPC synthesis, the ceramide is hydroxylated at C-4 by Sur2 (also called BasA in filamentous fungi) to form phytoceramide [38]. Alternatively, DHS can be hydroxylated to form the phytosphingosine (PHS) prior the ceramide condensation [38].…”

Section: Inositolphosphoceramidementioning

confidence: 99%

“…During IPC synthesis, the ceramide is hydroxylated at C-4 by Sur2 (also called BasA in filamentous fungi) to form phytoceramide [38]. Alternatively, DHS can be hydroxylated to form the phytosphingosine (PHS) prior the ceramide condensation [38]. In yeast, the C 26 fatty acid moiety contain 0 to 4 hydroxyl groups at C2, C3, C4 and C5 respectively [39,40].…”

Section: Inositolphosphoceramidementioning

confidence: 99%

Sphingolipids from the human fungal pathogen Aspergillus fumigatus

Fontaine

2017

Biochimie

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Syringomycin Action Gene SYR2 Is Essential for Sphingolipid 4-Hydroxylation in Saccharomyces cerevisiae

Cited by 143 publications

References 53 publications

Phytosphingosine as a Specific Inhibitor of Growth and Nutrient Import in Saccharomyces cerevisiae

Phytosphingosine as a Specific Inhibitor of Growth and Nutrient Import in Saccharomyces cerevisiae

Mutations in the Yeast LCB1 and LCB2Genes, Including Those Corresponding to the Hereditary Sensory Neuropathy Type I Mutations, Dominantly Inactivate Serine Palmitoyltransferase

Sphingolipids from the human fungal pathogen Aspergillus fumigatus

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