Acidification of the lysosome-like vacuole and the vacuolar H+-ATPase are deficient in two yeast mutants that fail to sort vacuolar proteins

J. H. Rothman, C. T. Yamashiro, C. K. Raymond, P. M. Kane, T. H. Stevens

Research output: Contribution to journalArticlepeer-review

45 Scopus citations


Organelle acidification plays a demonstrable role in intracellular protein processing, transport, and sorting in animal cells. We investigated the relationship between acidification and protein sorting in yeast by treating yeast cells with ammonium chloride and found that this lysosomotropic agent caused the mislocalization of a substantial fraction of the newly synthesized vacuolar (lysosomal) enzyme proteinase A (PrA) to the cell surface. We have also determined that a subset of the vpl mutants, which are deficient in sorting of vacuolar proteins (Rothman, J.H., and T.H. Stevens, 1986. Cell. 47:1041-1051; Rothman, J.H., I. Howald, and T.H. Stevens. EMBO (Eur. Mol. Biol. Organ.] J. In press), failed to accumulate the lysosomotropic fluorescent dye quinacrine within their vacuoles, mimicking the phenotype of wild-type cells treated with ammonium. The acidification defect of vpl3 and vpl6 mutants correlated with a marked deficiency in vacuolar ATPase activity, diminished levels of two immunoreactive subunits of the proton-translocating ATPase (H+-ATPase) in purified vacuolar membranes, and accumulation of the intracellular portion of PrA as the precursor species. Therefore, some of the VPL genes are required for the normal function of the yeast vacuolar H+-ATPase complex and may encode either subunits of the enzyme or components required for its assembly and targeting. Collectively, these findings implicate a critical role for acidification in vacuolar protein sorting and zymogen activation in yeast, and suggest that components of the yeast vacuolar acidification system may be identified by examining mutants defective in sorting of vacuolar proteins.

Original languageEnglish (US)
Pages (from-to)93-100
Number of pages8
JournalJournal of Cell Biology
Issue number1
StatePublished - 1989
Externally publishedYes

ASJC Scopus subject areas

  • Cell Biology


Dive into the research topics of 'Acidification of the lysosome-like vacuole and the vacuolar H+-ATPase are deficient in two yeast mutants that fail to sort vacuolar proteins'. Together they form a unique fingerprint.

Cite this