Catabolite inactivation of the yeast maltose transporter occurs in the vacuole after internalization by endocytosis.
The maltose transporter of Saccharomyces cerevisiae is rapidly degraded during fermentation in the absence of a nitrogen source. The location and mechanism of degradation of the transporter have been investigated. Using mutants defective in endocytosis, we have shown that degradation of this transporter requires internalization by endocytosis. In addition, studies of mutants defective in proteasome or vacuolar proteolysis revealed that degradation occurs in the vacuole and is independent of proteasome function. The results also revealed that degradation of the maltose transporter requires Sec18p and raised the question of whether in the absence of Sec18p activity the internalized maltose transporter is recycled back to the plasma membrane.
Riballo
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E
Instituto de Investigaciones Biomédicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain.
Herweijer
M
M
Wolf
D H
DH
Lagunas
R
R
D000251:Adenosine Triphosphatases; D001693:Biological Transport, Active; D002352:Carrier Proteins / Q000378:metabolism*; D003546:Cysteine Endopeptidases / Q000502:physiology; D004705:Endocytosis; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D008320:Maltose / Q000378:metabolism*; D009004:Monosaccharide Transport Proteins; D009097:Multienzyme Complexes / Q000502:physiology; D009154:Mutation; D046988:Proteasome Endopeptidase Complex; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D027981:Symporters; D013696:Temperature; D014617:Vacuoles / Q000378:metabolism*; D033921:Vesicular Transport Proteins
D002352:Carrier Proteins; D005656:Fungal Proteins; D009004:Monosaccharide Transport Proteins; D009097:Multienzyme Complexes; D029701:Saccharomyces cerevisiae Proteins; D027981:Symporters; D033921:Vesicular Transport Proteins; C067575:maltose transport system, S cerevisiae; D008320:Maltose; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex; D000251:Adenosine Triphosphatases; C064404:SEC18 protein, S cerevisiae