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

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

doi:10.1016/s0014-5793(00)01821-4

Cited by 34 publications

(20 citation statements)

References 28 publications

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“…Interestingly, it has previously been shown that sensitivity to another cyclic peptide, the pore-forming antifungal agent syringomycin E, also depends on the presence of fatty acid 2-hydroxylation because the scs7 mutant was also found to be resistant to this drug (3). One hypothesis, proposed by Hama et al (3), is that 2-hydroxylation would enhance the formation of sterol/sphingolipid-rich membrane domains (lipid rafts), which may serve as sites for syringomycin E binding and channel formation. This hypothesis is supported by the fact that mutants in other genes involved in sphingolipid biosynthesis are also resistant to the compound.…”

Section: Discussionmentioning

confidence: 99%

“…2-Hydroxy fatty acids are found almost exclusively as N-acyl chains within the ceramide moiety of a variety of sphingolipids. The functional role of fatty acid 2-hydroxylation has not been clearly established, but it seems to affect membrane conformation (3). We have found that 2-hydroxylated fatty acid-containing ceramides are involved in the mechanism of action of PM02734.…”

Section: Introductionmentioning

confidence: 87%

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Levels of SCS7/FA2H-Mediated Fatty Acid 2-Hydroxylation Determine the Sensitivity of Cells to Antitumor PM02734

et al. 2008

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PM02734 is a novel synthetic antitumor drug that is currently in phase I clinical trials. To gain some insight into its mode of action, we used the yeast Saccharomyces cerevisiae as a model system. Treatment of S. cerevisiae with PM02734 rapidly induced necrosis-like cell death, as also found for mammalian cells treated with its close analogue kahalalide F. We have screened the complete set of 4,848 viable S. cerevisiae haploid deletion mutants to identify genes involved in sensitivity or resistance to PM02734. Forty-five percent of the 40 most sensitive strains identified had a role in intracellular vesicle trafficking, indicating that the drug severely affects this process. A mutant strain lacking the sphingolipid fatty acyl 2-hydroxylase Scs7 was found to be the most resistant to PM02734, whereas overexpression of Scs7 rendered the cells hypersensitive to PM02734. To validate these findings in human cells, we did small interfering RNA experiments and also overexpressed the Scs7 human homologue FA2H in human cancer cell lines. As in yeast, FA2H silencing turned the cells resistant to the drug, whereas FA2H overexpression led to an increased sensitivity. Moreover, exogenous addition of the 2-hydroxylated fatty acid 2-hydroxy palmitic acid to different human cell lines increased their sensitivity to the cytotoxic compound. Taken together, these results suggest that the cell membrane and, in particular, 2-hydroxy fatty acidcontaining ceramides are important for PM02734 activity. These findings may have important implications in the development of PM02734 because tumor cells with high FA2H expression are expected to be particularly sensitive to this drug. [Cancer Res 2008;68(23):9779-87]

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 87%

Levels of SCS7/FA2H-Mediated Fatty Acid 2-Hydroxylation Determine the Sensitivity of Cells to Antitumor PM02734

et al. 2008

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“…FA containing lipid species participate in intramolecular and intermolecular hydrogen bonding and enhance the formation of sterol-and sphingolipid-enriched lipid rafts (30,31). Lipid composition plays an important role in regulating membrane mobility, and enhanced lateral mobility of raft-associated lipids decreases protein levels of GLUT4 and insulin receptor in 3T3-L1 adipocytes (16).…”

Section: Depletion Of Fa2h Increases Recovery Rate Of Frap Measuremenmentioning

confidence: 99%

Fatty Acid 2-Hydroxylase Mediates Diffusional Mobility of Raft-associated Lipids, GLUT4 Level, and Lipogenesis in 3T3-L1 Adipocytes

Guo

Zhou

Pryse

et al. 2010

Journal of Biological Chemistry

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Straight chain fatty acid ␣-oxidation increases during differentiation of 3T3-L1 adipocytes, leading to a marked accumulation of odd chain length fatty acyl moieties. Potential roles of this pathway in adipocyte differentiation and lipogenesis are unknown. Mammalian fatty acid 2-hydroxylase (FA2H) was recently identified and suggested to catalyze the initial step of straight chain fatty acid ␣-oxidation. Accordingly, we examined whether FA2H modulates adipocyte differentiation and lipogenesis in mature adipocytes. FA2H level markedly increases during differentiation of 3T3-L1 adipocytes, and small interfering RNAs against FA2H inhibit the differentiation process. In mature adipocytes, depletion of FA2H inhibits basal and insulin-stimulated glucose uptake and lipogenesis, which are partially rescued by the enzymatic product of FA2H, 2-hydroxy palmitic acid. Expression of fatty-acid synthase and SCD1 was decreased in FA2H-depleted cells, and levels of GLUT4 and insulin receptor proteins were reduced. 2-Hydroxy fatty acids are enriched in cellular sphingolipids, which are components of membrane rafts. Accelerated diffusional mobility of raft-associated lipids was shown to enhance degradation of GLUT4 and insulin receptor in adipocytes. Consistent with this, depletion of FA2H appeared to increase raft lipid mobility as it significantly accelerated the rates of fluorescence recovery after photobleaching measurements of lipid rafts labeled with Alexa 488-conjugated cholera toxin subunit B. Moreover, the enhanced recovery rates were partially reversed by treatment with 2-hydroxy palmitic acid. In conclusion, our findings document the novel role of FA2H in adipocyte lipogenesis possibly by modulation of raft fluidity and level of GLUT4.In addition to mitochondrial ␤-oxidation, fatty acids (FA) 2 can also be oxidized in peroxisomes, where they can undergo ␤-as well as ␣-oxidation. Peroxisomal ␣-oxidation produces fatty acyl moieties with one less carbon (odd chain length) without generating acetyl-CoA (1). It is well known that peroxisomal ␣-oxidation is important for catabolism of branched-chain FA and also for very long chain FA (2). Its contribution to catabolism of other long chain FA is not known, so its role in whole cell energy homeostasis remains unclear. There is evidence for up-regulation of FA ␣-oxidation during the preadipocyte to adipocyte transition as cells begin accumulating lipids. Using electrospray ionization-mass spectrometry and gas chromatography-coupled mass spectrometry, we and others demonstrated during differentiation of 3T3-L1 cells a marked increase in activity of peroxisomal FA ␣-oxidation, which was reflected in accumulation of odd chain length acyl moieties in major lipid species (3, 4). The underlying mechanisms for this change and the functions of the ␣-oxidation pathway in adipocyte differentiation and lipid metabolism in mature adipocytes have not been explored.Although straight chain FA ␣-oxidation was first reported in 1964 (5), a detailed understanding of the enzymatic pathway is sti...

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“…This activity is encoded by SCS7/FAH1 [25,56,57]. The biological function of this hydroxylation remains unclear; however, similar to the syr2 deletion, a scs7 deletion strain is less sensitive to certain fungicides that function by causing pore formation in the plasma membrane [33,[57][58][59]. This suggests that both the hydroxylations mediated by Syr2p and Fah1p affect lipid packing in membranes.…”

Section: Sphingolipid Metabolism In Yeast a De Novo Synthesismentioning

confidence: 99%

Yeast sphingolipids: Recent developments in understanding biosynthesis, regulation, and function

Cowart

Obeid

2007

Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biolog

120

112

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SummarySphingolipids function as required membrane components of virtually all eukaryotic cells. Data indicate that members of the sphingolipid family of lipids, including sphingoid bases, sphingoid base phosphates, ceramides, and complex sphingolipids, serve vital functions in cell biology by both direct mechanisms (e.g., binding to G-protein coupled receptors to transduce an extracellular signal) and indirect mechanisms (e.g., facilitating correct intracellular protein transport). Because of the diverse roles these lipids play in cell biology, it is important to understand not only their biosynthetic pathways and regulation of sphingolipid synthesis, but also the mechanisms by which some sphingolipid species with specific functions are modified or converted to other sphingolipid species with alternate functions. Due to many factors including ease of culture and genetic modification, and conservation of major sphingolipid metabolic pathways, Saccharomyces cerevisiae has served as an ideal model system with which to identify enzymes of sphingolipid biosynthesis and to dissect sphingolipid function. Recent exciting developments in sphingolipid synthesis, transport, signaling, and overall biology continue to fuel vigorous investigation and inspire investigations in mammalian sphingolipid biology.

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

Cited by 34 publications

References 28 publications

Levels of SCS7/FA2H-Mediated Fatty Acid 2-Hydroxylation Determine the Sensitivity of Cells to Antitumor PM02734

Levels of SCS7/FA2H-Mediated Fatty Acid 2-Hydroxylation Determine the Sensitivity of Cells to Antitumor PM02734

Fatty Acid 2-Hydroxylase Mediates Diffusional Mobility of Raft-associated Lipids, GLUT4 Level, and Lipogenesis in 3T3-L1 Adipocytes

Yeast sphingolipids: Recent developments in understanding biosynthesis, regulation, and function

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