An arf1Delta synthetic lethal screen identifies a new clathrin heavy chain conditional allele that perturbs vacuolar protein transport in Saccharomyces cerevisiae.

Chen CY, Graham TR
Genetics. 1998 150 (2): 577-89

PMID: 9755191 · PMCID: PMC1460353

ADP-ribosylation factor (ARF) is a small GTP-binding protein that is thought to regulate the assembly of coat proteins on transport vesicles. To identify factors that functionally interact with ARF, we have performed a genetic screen in Saccharomyces cerevisiae for mutations that exhibit synthetic lethality with an arf1Delta allele and defined seven genes by complementation tests (SWA1-7 for synthetically lethal with arf1Delta). Most of the swa mutants exhibit phenotypes comparable to arf1Delta mutants such as temperature-conditional growth, hypersensitivity to fluoride ions, and partial protein transport and glycosylation defects. Here, we report that swa5-1 is a new temperature-sensitive allele of the clathrin heavy chain gene (chc1-5), which carries a frameshift mutation near the 3' end of the CHC1 open reading frame. This genetic interaction between arf1 and chc1 provides in vivo evidence for a role for ARF in clathrin coat assembly. Surprisingly, strains harboring chc1-5 exhibited a significant defect in transport of carboxypeptidase Y or carboxypeptidase S to the vacuole that was not observed in other chc1 ts mutants. The kinetics of invertase secretion or transport of alkaline phosphatase to the vacuole were not significantly affected in the chc1-5 mutant, further implicating clathrin specifically in the Golgi to vacuole transport pathway for carboxypeptidase Y.

MeSH Terms (22)

ADP-Ribosylation Factor 1 ADP-Ribosylation Factors Alkaline Phosphatase Alleles Amino Acid Sequence beta-Fructofuranosidase Biological Transport Carboxypeptidases Cathepsin A Clathrin Clathrin Heavy Chains Frameshift Mutation Genes, Fungal Genes, Lethal Genetic Complementation Test Glycoside Hydrolases Golgi Apparatus GTP-Binding Proteins Molecular Sequence Data Saccharomyces cerevisiae Saccharomyces cerevisiae Proteins Vacuoles

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