Yeast mutants that are defective in acidification of the lysosome-like vacuole are able to grow at pH 5.5, but not at pH 7. Here, we present evidence that endocytosis is required for this low pH-dependent growth and use this observation to develop a screen for mutants defective in endocytosis. By isolating mutants that cannot grow when they lack the 60-kD vacuolar ATPase subunit (encoded by the VAT2 gene), we isolated a number of vat2-synthetic lethal (Vsl-) mutant strains. Seven of the Vsl- mutants are defective in endocytosis. Four of these mutant strains (end8-1, end9-1, end10-1, and end11-1) show altered uptake of the endocytosed ligand, α- factor, and three (end12-1, end12-2, and end13-1) are probably defective in transfer of internalized material to the vacuole. Most of the mutations also confer a strong Ts- growth defect. The mutants defective in uptake of α- factor sort newly synthesized vacuolar proteins correctly, while those which may be defective in subsequent transport steps secrete at least a fraction of the newly synthesized soluble vacuolar proteins. The mutations that result in a defect in α-factor uptake are not allelic to any of the genes previously shown to encode endocytic functions.
CITATION STYLE
Munn, A. L., & Riezman, H. (1994). Endocytosis is required for the growth of vacuolar H+-ATPase-defective yeast: Identification of six new END genes. Journal of Cell Biology, 127(2), 373–386. https://doi.org/10.1083/jcb.127.2.373
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