Title: | Protein transport to the vacuole and receptor-mediated endocytosis by clathrin heavy chain-deficient yeast |
Author(s): | Payne GS; Baker D; van Tuinen E; Schekman R; |
Address: | "Department of Biochemistry, University of California, Berkeley 94720" |
ISSN/ISBN: | 0021-9525 (Print) 1540-8140 (Electronic) 0021-9525 (Linking) |
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" |
Keywords: | "Animals Autoradiography Biological Transport Carboxypeptidases/metabolism Cathepsin A Clathrin/genetics/*physiology Densitometry Electrophoresis, Polyacrylamide Gel *Endocytosis Enzyme Precursors/metabolism Fungal Proteins/*metabolism Immunohistochemistry;" |
Notes: | "MedlinePayne, G S Baker, D van Tuinen, E Schekman, R eng Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, Non-P.H.S. Research Support, U.S. Gov't, P.H.S. 1988/05/01 J Cell Biol. 1988 May; 106(5):1453-61. doi: 10.1083/jcb.106.5.1453" |