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Yeast uracil permease follows the secretory pathway to the plasma membrane and is phosphorylated on serine residues in a post-Golgi compartment. The protein was found to be rather stable in growing cells, but its turnover rate (half-life of about 7 h) was much faster than that of most yeast proteins. Several adverse conditions triggered the rapid(More)
Nine new hem12 haploid mutants of baker's yeast (Saccharomyces cerevisiae), totally or partially deficient in uroporphyrinogen decarboxylase activity, were subjected to both genetic and biochemical analysis. The mutations sites studied are situated far apart within the HEM12 gene located on chromosome IV. Uroporphyrinogen decarboxylase activity in the(More)
Uptake of uracil by the yeast Saccharomyces cerevisiae is mediated by a specific permease encoded by the FUR4 gene. Uracil permease located at the cell surface is subject to two covalent modifications: phosphorylation and ubiquitination. The ubiquitination step is necessary prior to permease endocytosis and subsequent vacuolar degradation. Here, we(More)
Endocytosis is involved in a wide variety of cellular processes, and the internalization step of endocytosis has been extensively studied in both lower and higher eukaryotic cells. Studies in mammalian cells have described several endocytic pathways, with the main emphasis on clathrin-dependent endocytosis. Genetic studies in yeast have underlined the(More)
The ubiquitin ligase (E3) Rsp5p is the only member of the Nedd (neural-precursor-cell-expressed, developmentally down-regulated) 4 family of E3s present in yeast. Rsp5p has several proteasome-independent functions in membrane protein trafficking, including a role in the ubiquitination of most plasma membrane proteins, leading to their endocytosis. Rsp5p is(More)
Rsp5p is an ubiquitin (Ub)-protein ligase of the Nedd4 family that carries WW domains involved in interaction with PPXY-containing proteins. It plays a key role at several stages of intracellular trafficking, such as Ub-mediated internalization of endocytic cargoes and Ub-mediated sorting of membrane proteins to internal vesicles of multivesicular bodies(More)
Uracil uptake by Saccharomyces cerevisiae is mediated by the FUR4-encoded uracil permease. The modification of uracil permease by phosphorylation at the plasma membrane is a key mechanism for regulating endocytosis of this protein. This modification in turn facilitates its ubiquitination and internalization. Following endocytosis, the permease is targeted(More)
In a multiple deletion mutant hxtlAhxt2Ahxt3A hxt4Asn]'3A of Saccharomyces cerevisiae growing on 2 % glucose, high-affinity glucose-uptake (low Kin) was exhibited throughout growth on glucose in contrast to the wild-type, which exhibited the usual low-affinity to high-affinity transition as the glucose in the medium was consumed. Elevated levels of(More)
The yeast uracil permease, Fur4p, is downregulated by uracil, which is toxic to cells with high permease activity. Uracil promotes cell surface Rsp5p-dependent ubiquitylation of the permease, signaling its endocytosis and further vacuolar degradation. We show here that uracil also triggers the direct routing of its cognate permease from the Golgi apparatus(More)
The biosynthesis of yeast 5-aminolevulinate (ALA) synthase, a mitochondrial protein encoded by the nuclear HEM1 gene, has been studied in vitro in a cell-free translation system and in vivo in whole cells. In vitro translation of mRNA hybrid-selected by the cloned HEM1 gene, or of total RNA followed by immunoprecipitation with anti-(ALA synthase) antibody(More)