Protein transport to the vacuole and receptor-mediated endocytosis by clathrin heavy chain-deficient yeast

TitleProtein transport to the vacuole and receptor-mediated endocytosis by clathrin heavy chain-deficient yeast
Publication TypeJournal Article
Year of Publication1988
AuthorsPayne, G. S., Baker D., van Tuinen E., & Schekman R.
JournalThe Journal of cell biology
Volume106
Issue5
Pagination1453-61
Date Published1988 May
ISSN0021-9525
KeywordsAnimals, Autoradiography, Biological Transport, Carboxypeptidases, Cathepsin A, Clathrin, Densitometry, Electrophoresis, Polyacrylamide Gel, Endocytosis, Enzyme Precursors, Fungal Proteins, Immunohistochemistry, Kinetics, Microscopy, Electron, Mutation, Organoids, Peptides, Pheromones, Primary Publication, Receptors, Cell Surface, Receptors, Mating Factor, Receptors, Peptide, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Transcription Factors, Vacuoles
Abstract

Clathrin heavy chain-deficient mutants (chcl) of Saccharomyces cerevisiae are viable but exhibit compromised growth rates. To investigate the role of clathrin in intercompartmental protein transport, two pathways have been monitored in chcl cells: transport of newly synthesized vacuolar proteins to the vacuole and receptor-mediated uptake of mating pheromone. Newly synthesized precursors of the vacuolar protease carboxypeptidase Y (CPY) were converted to mature CPY with similar kinetics in mutant and wild-type cells. chcl cells did not aberrantly secrete CPY and immunolocalization techniques revealed most of the CPY in chcl cells within morphologically identifiable vacuolar structures. Receptor-mediated internalization of the mating pheromone alpha-factor occurred in chcl cells at 36-50% wild-type levels. The mutant cells were fully competent to respond to pheromone-induced cell-cycle arrest. These results argue that in yeast, clathrin may not play an essential role either in vacuolar protein sorting and delivery or in receptor-mediated endocytosis of alpha-factor. Alternative mechanisms ordinarily may execute these pathways, or be activated in clathrin-deficient cells.

Alternate JournalJ. Cell Biol.
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