Reference - Detail
|Author||Umebayashi K, Nakano A.|
|Title||Ergosterol is required for targeting of tryptophan permease to the yeast plasma membrane.|
|Journal||J. Cell Biol.|
It was known that the uptake of tryptophan is reduced in the yeast erg6 mutant, which is defective in a late step of ergosterol biosynthesis. Here, we show that this is because the high affinity tryptophan permease Tat2p is not targeted to the plasma membrane. In wild-type cells, the plasma membrane localization of Tat2p is regulated by the external tryptophan concentration. Tat2p is transported from the Golgi apparatus to the vacuole at high tryptophan, and to the plasma membrane at low tryptophan. However, in the erg6 mutant, Tat2p is missorted to the vacuole at low tryptophan. The plasma membrane targeting of Tat2p is dependent on detergent-insoluble membrane domains, suggesting that sterol affects the sorting through the organization of lipid rafts. The erg6 mutation also caused missorting to the multivesicular body pathway in late endosomes. Thus, sterol composition is crucial for protein sorting late in the secretory pathway. Tat2p is subject to polyubiquitination, which acts as a vacuolar-targeting signal, and the inhibition of this process suppresses the Tat2p sorting defects of the erg6 mutant. The sorting mechanisms of Tat2p that depend on both sterol and ubiquitin will be discussed.
|MeSH||Amino Acid Transport Systems / metabolism* Cell Membrane / enzymology* Cells, Cultured Endosomes / metabolism Ergosterol / metabolism* Membrane Microdomains / enzymology* Mutation / genetics Protein Structure, Tertiary / genetics Protein Transport / genetics* Saccharomyces cerevisiae / cytology Saccharomyces cerevisiae / enzymology* Saccharomyces cerevisiae / genetics Saccharomyces cerevisiae Proteins / metabolism* Transport Vesicles / enzymology Tryptophan / metabolism* Ubiquitin / metabolism Vacuoles / enzymology|
|WOS Category||CELL BIOLOGY|
|DNA material||pKU1 (RDB08559) pKU105 (RDB08570) pKU106 (RDB08571) pKU108 (RDB08572) pKU121 (RDB08573) pKU131 (RDB08574) pKU158 (YCpTAT23K>R-3HA) (RDB08575) pKU41 (RDB08560) pKU46 (YCpTAT2?3HA) (RDB08561) pKU51 (RDB08562) pKU60 (RDB08563) pKU62 (RDB08564) pKU65 (RDB08565) pKU68 (RDB08566) pKU76 (YCpTAT2-GFP) (RDB08567) pKU82 (RDB08568) pKU84 (RDB08569)|