The ergosterol biosynthesis inhibitor zaragozic acid promotes vacuolar degradation of the tryptophan permease Tat2p in yeast

Daicho, Katsue; Maruyama, Hironori; Suzuki, Asuka; Ueno, Masaru; Uritani, Masahiro; Ushimaru, Takashi

doi:10.1016/j.bbamem.2007.03.022

Cited by 18 publications

(16 citation statements)

References 42 publications

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“…For instance, the inhibition of ergosterol synthesis or the mutation of erg6 or erg2 promotes the abnormal sorting of the tryptophan permease Tat2 to the plasma membrane (4,5). However, at least in the case of erg6, although we observed a significant decrease in potassium uptake, which likely explains the growth defect in low-potassium medium, the amount of Trk1 at the plasma membrane was not drastically reduced.…”

Section: Discussionmentioning

confidence: 59%

A Genomewide Screen for Tolerance to Cationic Drugs Reveals Genes Important for Potassium Homeostasis in Saccharomyces cerevisiae

et al. 2011

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Potassium homeostasis is crucial for living cells. In the yeast Saccharomyces cerevisiae, the uptake of potassium is driven by the electrochemical gradient generated by the Pma1 H ؉ -ATPase, and this process represents a major consumer of the gradient. We considered that any mutation resulting in an alteration of the electrochemical gradient could give rise to anomalous sensitivity to any cationic drug independently of its toxicity mechanism. Here, we describe a genomewide screen for mutants that present altered tolerance to hygromycin B, spermine, and tetramethylammonium. Two hundred twenty-six mutant strains displayed altered tolerance to all three drugs (202 hypersensitive and 24 hypertolerant), and more than 50% presented a strong or moderate growth defect at a limiting potassium concentration (1 mM). Functional groups such as protein kinases and phosphatases, intracellular trafficking, transcription, or cell cycle and DNA processing were enriched. Essentially, our screen has identified a substantial number of genes that were not previously described to play a direct or indirect role in potassium homeostasis. A subset of 27 representative mutants were selected and subjected to diverse biochemical tests that, in some cases, allowed us to postulate the basis for the observed phenotypes.

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Section: Discussionmentioning

confidence: 59%

A Genomewide Screen for Tolerance to Cationic Drugs Reveals Genes Important for Potassium Homeostasis in Saccharomyces cerevisiae

et al. 2011

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“…To detect Tat2, plasmids pSCU301 (pHA2‐TAT2) and pSCU425 (pHA2‐TAT2‐5KR) (Beck et al ., 1999) were used. The composition of adenine‐containing rich medium (YPAD; yeast extract, peptone, adenine and 2% glucose) and synthetic minimal medium (SD) were described previously (Daicho et al ., 2007). Normal SD medium contained 20 μg mL −1 of tryptophan.…”

Section: Methodsmentioning

confidence: 99%

“…Western blot analysis was performed in accordance with the previous report (Daicho et al ., 2007), using anti‐HA (HA, hemagglutinin) mouse monoclonal (16B12, BAbCo), anti‐Pep12 mouse monoclonal (Molecular Probes Inc.), anti‐Pma1 mouse monoclonal (40B7, EnCor Biotechnology Inc., Gainesville, Florida), and anti‐Cdk rabbit polyclonal (PSTAIRE, Santa Cruz) antibodies.…”

Section: Methodsmentioning

confidence: 99%

“…Thus, targeting of Tat2 to the plasma membrane is compromised in erg6 Δ cells, but vacuolar sorting of Tat2 is not stimulated. In contrast, inhibition of ERG9 ‐encoded squalene synthetase (SQS) by zaragozic acid (ZA) promotes the vacuolar degradation of Tat2 (Daicho et al ., 2007). SQS catalyzes the conversion of farnesyl pyrophosphate to squalene.…”

Section: Introductionmentioning

confidence: 99%

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Sorting defects of the tryptophan permease Tat2 in anerg2yeast mutant

Daicho

Makino

Hiraki

et al. 2009

FEMS Microbiology Letters

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Cholesterol (ergosterol in yeast) in conjunction with sphingolipids forms tight-packing microdomains, 'lipid rafts,' which are thought to be critical for intracellular protein sorting in eukaryotic cells. When the activity of Erg9 involved in the first step of ergosterol biogenesis, but not that of Erg6 involved in a late step, is compromised, vacuolar degradation of the tryptophan permease Tat2 is promoted. It is unknown whether this difference simply reflects the difference between the inhibition of early and late steps. Here, it is shown that the deletion in ERG2, which encodes sterol C8-C7 isomerase (the next enzymatic step after Erg6), promotes the vacuolar degradation of Tat2. It suggests that the accumulation of specific sterol intermediates may alter lipid raft structures, promoting Tat2 degradation. The erg2Delta-mediated Tat2 degradation required Tat2 ubiquitination. Lipid raft association of Tat2 is compromised in erg2Delta cells. The erg2Delta mutation showed a synthetic growth defect with the trp1 mutation, indicating that Tat2 sorting is preferentially compromised in these mutants. Consistent with this notion, the raft-associated protein Pma1 was associated with detergent-resistant membranes and sorted to the plasma membrane. This study suggests the potential for the pharmacological control of cellular nutrient uptake in humans by regulating enzymes involved in cholesterol biogenesis.

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“…In wild-type cells, Tat2p is transported from the Golgi apparatus to the vacuole at high tryptophan level, and to the plasma membrane at low tryptophan level. However, Tat2p is missorted to the vacuole at low tryptophan concentration in the erg6 Δ deleted mutant ( ERG6 gene encodes S -adenosylmethionine Δ24 methyltransferase, acting in the last steps of ergosterol biosynthesis by converting zymosterol to fecosterol; Umebayashi and Nakano, 2003), and following yeast treatment with the ergosterol biosynthesis inhibitor zaragozic acid, that inhibits squalene synthetase, which catalyzes the first committed step in the formation of cholesterol/ergosterol (Daicho et al, 2007). Likewise, additional proteins, such as Fus1p, a plasma membrane protein required for yeast mating, is excluded from rafts and missorted to the vacuole in the erg6 Δ mutant (Bagnat and Simons, 2002).…”

Section: Nutrient Transporters In Yeast Lipid Raftsmentioning

confidence: 99%

Lipid raft involvement in yeast cell growth and death

Mollinedo¹

2012

Front. Oncol.

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The notion that cellular membranes contain distinct microdomains, acting as scaffolds for signal transduction processes, has gained considerable momentum. In particular, a class of such domains that is rich in sphingolipids and cholesterol, termed as lipid rafts, is thought to compartmentalize the plasma membrane, and to have important roles in survival and cell death signaling in mammalian cells. Likewise, yeast lipid rafts are membrane domains enriched in sphingolipids and ergosterol, the yeast counterpart of mammalian cholesterol. Sterol-rich membrane domains have been identified in several fungal species, including the budding yeast Saccharomyces cerevisiae, the fission yeast Schizosaccharomyces pombe as well as the pathogens Candida albicans and Cryptococcus neoformans. Yeast rafts have been mainly involved in membrane trafficking, but increasing evidence implicates rafts in a wide range of additional cellular processes. Yeast lipid rafts house biologically important proteins involved in the proper function of yeast, such as proteins that control Na+, K+, and pH homeostasis, which influence many cellular processes, including cell growth and death. Membrane raft constituents affect drug susceptibility, and drugs interacting with sterols alter raft composition and membrane integrity, leading to yeast cell death. Because of the genetic tractability of yeast, analysis of yeast rafts could be an excellent model to approach unanswered questions of mammalian raft biology, and to understand the role of lipid rafts in the regulation of cell death and survival in human cells. A better insight in raft biology might lead to envisage new raft-mediated approaches to the treatment of human diseases where regulation of cell death and survival is critical, such as cancer and neurodegenerative diseases.

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The ergosterol biosynthesis inhibitor zaragozic acid promotes vacuolar degradation of the tryptophan permease Tat2p in yeast

Cited by 18 publications

References 42 publications

A Genomewide Screen for Tolerance to Cationic Drugs Reveals Genes Important for Potassium Homeostasis in Saccharomyces cerevisiae

A Genomewide Screen for Tolerance to Cationic Drugs Reveals Genes Important for Potassium Homeostasis in Saccharomyces cerevisiae

Sorting defects of the tryptophan permease Tat2 in anerg2yeast mutant

Lipid raft involvement in yeast cell growth and death

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