Compartment acidification is required for efficient sorting of proteins to the vacuole in Saccharomyces cerevisiae

Daniel J. Klionsky*, Hannah Nelson, Nathan Nelson

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

73 Scopus citations

Abstract

The vacuole of the yeast Saccharomyces cerevisiae contains a proton-translocating ATPase that acidifies the vacuolar lumen and generates a pH gradient across the vacuole membrane. We have investigated the role of compartment acidification of the vacuolar system in the sorting of vacuolar proteins. Strains with chromosomal disruptions of the genes encoding the A, B, or c subunit of the vacuolar ATPase are unable to acidify their vacuoles. These vat mutant strains accumulate and secrete precursor forms of the soluble vacuolar hydrolases carboxypeptidase Y and proteinase A. The kinetics of secretion suggests that missorting occurs in the Golgi complex or in post-Golgi vesicles. The presence of mature forms of the vacuolar proteins within the cell indicates that vat mutations do not cause defects in zymogen processing. Precursor forms of the membrane-associated vacuolar hydrolase alkaline phosphatase are also accumulated in vat mutant cells but to a lesser extent, suggesting that sorting of vacuolar membrane proteins is less sensitive to changes in the lumenal pH. A similar type of missorting defect can be induced in wild-type cells at pH 7.5. These results indicate that acidification of the vacuolar system is important for efficient sorting of proteins to the vacuole.

Original languageEnglish
Pages (from-to)3416-3422
Number of pages7
JournalJournal of Biological Chemistry
Volume267
Issue number5
StatePublished - 15 Feb 1992
Externally publishedYes

Funding

FundersFunder number
National Institute of Diabetes and Digestive and Kidney DiseasesR01DK043684

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