Syringomycin E Inhibition of
            <i>Saccharomyces cerevisiae</i>
            : Requirement for Biosynthesis of Sphingolipids with Very-Long-Chain Fatty Acids and Mannose- and Phosphoinositol-Containing Head Groups

Stock, Stephen D.; Hama, Hiroko; Radding, Jeffrey A; Young, Debra A.; Takemoto, Jon Y.

doi:10.1128/aac.44.5.1174-1180.2000

Cited by 75 publications

(72 citation statements)

References 42 publications

(51 reference statements)

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“…SRE affects fungal membrane permeability by processes that are likely related to channel formation [22,23]. Several sphingolipid biosynthetic genes, one of which is IPT1, were found to be involved in SRE-susceptibility of S. cerevisiae [23].…”

Section: Discussionmentioning

confidence: 99%

SKN1, a novel plant defensin‐sensitivity gene in Saccharomyces cerevisiae, is implicated in sphingolipid biosynthesis

Thevissen

Idkowiak-Baldys

et al. 2005

FEBS Letters

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The antifungal plant defensin DmAMP1 interacts with the fungal sphingolipid mannosyl diinositolphosphoryl ceramide (M(IP) 2 C) and induces fungal growth inhibition. We have identified SKN1, besides the M(IP) 2 C-biosynthesis gene IPT1, as a novel DmAMP1-sensitivity gene in Saccharomyces cerevisiae. SKN1 was previously shown to be a KRE6 homologue, which is involved in b-1,6-glucan biosynthesis. We demonstrate that a Dskn1 mutant lacks M(IP) 2 C. Interestingly, overexpression of either IPT1 or SKN1 complemented the skn1 mutation, conferred sensitivity to DmAMP1, and resulted in M(IP) 2 C levels comparable to the wild type. These results show that SKN1, together with IPT1, is involved in sphingolipid biosynthesis in S. cerevisiae.

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Section: Discussionmentioning

confidence: 99%

SKN1, a novel plant defensin‐sensitivity gene in Saccharomyces cerevisiae, is implicated in sphingolipid biosynthesis

Thevissen

Idkowiak-Baldys

et al. 2005

FEBS Letters

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“…Phenotypic studies involved drug (Sigma) supplementation with caffeine (5 to 7.5 mM), hygromycin B (100 g/ml), nystatin (50 g/ml), Calcofluor White (50 g/ml), or 6% (vol/vol) ethanol. Recovery from heat shock and syringomycin E assays followed previous protocols (26,58). Zymocin responses by killer eclipse assays involved K. lactis killer AWJ137 (Table 1) and growth for 1 day at 30°C (36).…”

Section: Methodsmentioning

confidence: 99%

Mannosyl-Diinositolphospho-Ceramide, the Major Yeast Plasma Membrane Sphingolipid, Governs Toxicity of Kluyveromyces lactis Zymocin

et al. 2005

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Kluyveromyces lactis zymocin, a trimeric (␣␤␥) protein toxin complex, inhibits proliferation of Saccharomyces cerevisiae cells. Here we present an analysis of kti6 mutants, which resist exogenous zymocin but are sensitive to intracellular expression of its inhibitory ␥-toxin subunit, suggesting that KTI6 encodes a factor needed for toxin entry into the cell. Consistent with altered cell surface properties, kti6 cells resist hygromycin B, syringomycin E, and nystatin, antibiotics that require intact membrane potentials or provoke membrane disruption. KTI6 is allelic to IPT1, coding for mannosyl-diinositolphospho-ceramide [M(IP) 2 C] synthase, which produces M(IP) 2 C, the major plasma membrane sphingolipid. kti6 membranes lack M(IP) 2 C and sphingolipid mutants that have reduced levels of M(IP) 2 C precursors, including the sphingolipid building block ceramide survive zymocin. In addition, kti6/ipt1 cells allow zymocin docking but prevent import of its toxic ␥-subunit. Genetic analysis indicates that Kti6 is likely to act upstream of lipid raft proton pump Kti10/Pma1, a previously identified zymocin sensitivity factor. In sum, M(IP) 2 C operates in a plasma membrane step that follows recognition of cell wall chitin by zymocin but precedes the involvement of elongator, the potential toxin target.

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“…TCA was added to cultures at a final concentration of 5%, and total lipids were extracted by addition of 0.5 ml of ethanol/ ether/water/pyridine/ammonium hydroxide (15:5:15:1:0.018, v/v) as described previously (32). Lipids were deacylated in chloroform/methanol/water (16:16:5, v/v) containing an equal volume of 0.2 N NaOH in methanol as described previously (39). Mixtures were neutralized by the addition of 1 N acetic acid containing 0.5% EDTA (w/v).…”

Section: Methodsmentioning

confidence: 99%

“…Nondeacylated lipids, which contain the labeled sphingolipids, were extracted with chloroform, dried under N 2 , and resuspended in chloroform/ methanol/water (16:16:5, v/v). Radiolabeled sphingolipids were separated by two-dimensional TLC as described by Stock et al (39). Quantitation was performed following scanning on a STORM 860 PhosphorImager and analyzed using ImageQuant software (GE Healthcare).…”

Section: Methodsmentioning

confidence: 99%

Interruption of Inositol Sphingolipid Synthesis Triggers Stt4p-dependent Protein Kinase C Signaling

Jesch

Gaspar

Stefan

et al. 2010

Journal of Biological Chemistry

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The protein kinase C (PKC)-MAPK signaling cascade is activated and is essential for viability when cells are starved for the phospholipid precursor inositol. In this study, we report that inhibiting inositol-containing sphingolipid metabolism, either by inositol starvation or treatment with agents that block sphingolipid synthesis, triggers PKC signaling independent of sphingoid base accumulation. Under these same growth conditions, a fluorescent biosensor that detects the necessary PKC signaling intermediate, phosphatidylinositol (PI)-4-phosphate (PI4P), is enriched on the plasma membrane. The appearance of the PI4P biosensor on the plasma membrane correlates with PKC activation and requires the PI 4-kinase Stt4p. Like other mutations in the PKC-MAPK pathway, mutants defective in Stt4p and the PI4P 5-kinase Mss4p, which generates phosphatidylinositol 4,5-bisphosphate, exhibit inositol auxotrophy, yet fully derepress INO1, encoding inositol-3-phosphate synthase. These observations suggest that inositol-containing sphingolipid metabolism controls PKC signaling by regulating access of the signaling lipids PI4P and phosphatidylinositol 4,5-bisphosphate to effector proteins on the plasma membrane.The protein kinase C (PKC) pathway, also known in yeast as the cell wall integrity pathway, is a highly conserved signal transduction pathway that is activated in Saccharomyces cerevisiae during periods of polarized cell growth (1, 2) as well as by numerous environmental stresses, including elevated temperature (3), entry into stationary growth phase (4), and treatment with agents that interfere with cell wall biogenesis (5, 6). Signals produced on the cell surface are amplified and relayed by PKC to downstream targets through a three-component MAPK phosphorylation cascade composed of the MEK kinase Bck1p, the redundant MEKs Mkk1p and Mkk2p, and the MAPK Slt2p (Fig. 1A). Pkc1p homologs in mammals are directly regulated by lipids, including diacylglycerol (DAG) 2 produced by hydrolysis of phosphatidylinositol 4,5-bisphosphate (PI(4,5)P 2 ), anionic phospholipids, and sphingolipids (7,8). Nevertheless, these lipid metabolites do not appear to play identical roles in yeast PKC activation.In yeast, the phosphorylated derivatives of phosphatidylinositol (PI), phosphatidylinositol 4-phosphate (PI4P) and PI(4,5)P 2 , are essential for PKC signaling during heat stress (9). PI4P is produced on the plasma membrane by the PI 4-kinase Stt4p and is subsequently phosphorylated to PI(4,5)P 2 by the PI4P 5-kinase Mss4p. Stt4p was originally identified in a genetic screen for mutants that are hypersensitive to staurosporine, a specific inhibitor of PKC (10). Mutations in both STT4 and MSS4 cause cell lysis phenotypes associated with defects in cell wall integrity signaling, and these defects are suppressed by overexpression of PKC1 (10, 11). Stt4p-dependent pools of PI4P and PI(4,5)P 2 are proposed to regulate PKC signaling by plasma membrane recruitment of the guanine nucleotide exchange factor Rom2p, where it carries out multiple function...

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Syringomycin E Inhibition of Saccharomyces cerevisiae : Requirement for Biosynthesis of Sphingolipids with Very-Long-Chain Fatty Acids and Mannose- and Phosphoinositol-Containing Head Groups

Cited by 75 publications

References 42 publications

SKN1, a novel plant defensin‐sensitivity gene in Saccharomyces cerevisiae, is implicated in sphingolipid biosynthesis

SKN1, a novel plant defensin‐sensitivity gene in Saccharomyces cerevisiae, is implicated in sphingolipid biosynthesis

Mannosyl-Diinositolphospho-Ceramide, the Major Yeast Plasma Membrane Sphingolipid, Governs Toxicity of Kluyveromyces lactis Zymocin

Interruption of Inositol Sphingolipid Synthesis Triggers Stt4p-dependent Protein Kinase C Signaling

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