Yeast genes involved in growth inhibition by<i>Pseudomonas syringae</i>pv.<i>syringae</i>syringomycin family lipodepsipeptides

Takemoto, Jon Y.; Yu, Yan; Stock, Stephen D.; Miyakawa, Tokichi

doi:10.1111/j.1574-6968.1993.tb06595.x

Cited by 26 publications

(5 citation statements)

References 13 publications

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“…Previous analyses of syringomycin E‐resistant yeast mutants, generated by nitrosoguanidine mutagenesis, identified 11 genes that are involved in susceptibility to syringomycin E [7–10]. To isolate additional mutants, rigorous UV irradiation mutagenesis was conducted (survival rate of 10%).…”

Section: Resultsmentioning

confidence: 99%

“…S. cerevisiae contains lipid rafts that are highly enriched with ergosterol and sphingolipids, and depletion of these lipids compromises raft integrity [26]. In addition to HFA, the antifungal action of syringomycin E also requires ergosterol [7,9] and sphingolipid modifications that increase lipid–lipid interactions [8,10,20], suggesting further the involvement of lipid rafts. Association of syringomycin E to lipid rafts would increase local concentrations to facilitate formation of the oligomeric syringomycin E channels.…”

Section: Discussionmentioning

confidence: 99%

“…To understand the mechanism of action of syringomycin E in biological membranes, the yeast Saccharomyces cerevisiae has been used as a model target organism. Characterization of syringomycin E‐resistant yeast mutants has revealed at least 11 genes that, when mutated, result in a resistant phenotype [7,8]. These genes are involved in sterol biosynthesis ( SYR1/ERG3 and four uncharacterized genes) [7,9] or sphingolipid biosynthesis ( SYR2, SYR3/ELO2, ELO3, SYR4/IPT1, CSG1, CSG2 ) [8,10].…”

Section: Introductionmentioning

confidence: 99%

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Requirement of sphingolipid α‐hydroxylation for fungicidal action of syringomycin E

Hama¹,

Young²,

Radding³

et al. 2000

FEBS Letters

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Syringomycin E is an antifungal cyclic lipodepsinonapeptide produced by Pseudomonas syringae pv. syringae. To understand the mechanism of action of syringomycin E, a novel resistant Saccharomyces cerevisiae strain, BW7, was isolated and characterized. Lipid analyses revealed that BW7 contained only the hydrophobic subspecies of sphingolipids that are normally minor components in wild type strains. This aberrant sphingolipid composition was the result of lack of K K-hydroxylation of the amide-linked very long chain fatty acids, suggesting a defective sphingolipid K K-hydroxylase encoded by the FAH1 gene. A yeast strain that lacks the FAH1 gene was resistant to syringomycin E, and failed to complement BW7. These results demonstrate that BW7 carries a mutation in the FAH1 gene, and that the lack of K K-hydroxylated very long chain fatty acids in yeast sphingolipids confers resistance to syringomycin E. ß

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Requirement of sphingolipid α‐hydroxylation for fungicidal action of syringomycin E

Hama¹,

Young²,

Radding³

et al. 2000

FEBS Letters

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“…To further investigate the molecular mechanisms of action of this bioactive compound, resistant mutants of Saccharomyces cerevisiae were isolated to identify genes that encode proteins necessary for growth inhibition by syringomycin E (7). Several of the mutants were deficient in sterols, and one group was complemented by the gene SYR1 (identical to ERG3), which encodes sterol C-5,6 desaturase of the ergosterol biosynthetic pathway (8).…”

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confidence: 99%

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

Grilley

Stock

Dickson

et al. 1998

Journal of Biological Chemistry

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143

123

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The Saccharomyces cerevisiae gene SYR2, necessary for growth inhibition by the cyclic lipodepsipeptide syringomycin E, is shown to be required for 4-hydroxylation of long chain bases in sphingolipid biosynthesis. Four lines of support for this conclusion are presented: (a) the predicted Syr2p shows sequence similarity to diiron-binding membrane enzymes involved in oxygendependent modifications of hydrocarbon substrates, (b) yeast strains carrying a disrupted SYR2 allele produced sphingoid long chain bases lacking the 4-hydroxyl group present in wild type strains, (c) 4-hydroxylase activity was increased in microsomes prepared from a SYR2 overexpression strain, and (d) the syringomycin E resistance phenotype of a syr2 mutant strain was suppressed when grown under conditions in which exogenous 4-hydroxysphingoid long chain bases were incorporated into sphingolipids. The syr2 strain produced wild type levels of sphingolipids, substantial levels of hydroxylated very long chain fatty acids, and the full complement of normal yeast sphingolipid head groups. These results show that the SYR2 gene is required for the 4-hydroxylation reaction of sphingolipid long chain bases, that this hydroxylation is not essential for growth, and that the 4-hydroxyl group of sphingolipids is necessary for syringomycin E action on yeast.Syringomycin E is a member of a family of cyclic lipodepsipeptides produced by strains of the plant bacterium Pseudomonas syringae pv. syringae (1). Traditionally regarded as a virulence factor in a variety of bacterial necrotic diseases of plants (2), syringomycin E and its analogs also possess antifungal properties, and it has been suggested that these metabolites are fungal antagonists that aid survival of the producing bacteria on plants (3, 4).How these compounds produce their toxic effects is unknown, but past physiological studies have shown that syringomycin E targets primarily the plasma membrane (1, 5, 6). To further investigate the molecular mechanisms of action of this bioactive compound, resistant mutants of Saccharomyces cerevisiae were isolated to identify genes that encode proteins necessary for growth inhibition by syringomycin E (7). Several of the mutants were deficient in sterols, and one group was complemented by the gene SYR1 (identical to ERG3), which encodes sterol C-5,6 desaturase of the ergosterol biosynthetic pathway (8). These findings, when combined with results from binding (9) and lipid bilayer (10) studies, indicate that sterols influence the interaction of syringomycin E with the target plasma membrane.Syringomycin E action in yeast was more recently shown to require a second, nonsterol biosynthetic gene, SYR2 (11). SYR2 is identical to SUR2, which was identified in a screen for mutants that suppress the impaired recovery of rvs161 strains from nutritional starvation (12). Syringomycin E-resistant syr2 mutants showed altered glycerophospholipid levels, and the SYR2 gene product was localized to the endoplasmic reticulum (11). Nevertheless, the precise function of Syr2p was ...

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“…Other structural features of yeast sphingolipids also promote syringomycin E action [8][9][10]. These, as well as C4 hydroxylation, contribute to the hydrogen bonding abilities of the sphingolipids.…”

Section: Introductionmentioning

confidence: 99%

Sphingolipid C4 hydroxylation influences properties of yeast detergent‐insoluble glycolipid‐enriched membranes

2004

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Sphingoid base C4 hydroxylation is required for syringomycin E action on the yeast plasma membrane. Detergent-insoluble glycolipid-enriched membranes (DIGs) from a yeast strain lacking C4 hydroxylated sphingoid bases (sur2D) are composed of linear membrane fragments instead of vesicular structures observed for wild-type DIGs, though they have similar lipid compositions and amounts of DIG marker proteins. Lightscattering bands collected from sur2D after centrifugation of Triton X-100-treated cell lysates in continuous density gradients have lower buoyant densities than that of the wild-type. The results show that C4 hydroxylation influences the physical and structural properties of DIGs and suggest that syringomycin E interacts with lipid rafts.

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Yeast genes involved in growth inhibition byPseudomonas syringaepv.syringaesyringomycin family lipodepsipeptides

Cited by 26 publications

References 13 publications

Requirement of sphingolipid α‐hydroxylation for fungicidal action of syringomycin E

Requirement of sphingolipid α‐hydroxylation for fungicidal action of syringomycin E

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

Sphingolipid C4 hydroxylation influences properties of yeast detergent‐insoluble glycolipid‐enriched membranes

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