title: Identification and characterization of Saccharomyces cerevisiae mutants defective in fluid-phase endocytosis.
abstract: A mutant library generated by the European Functional Analysis Network (EUROFAN) was screened for strains defective in fluid-phase endocytosis. Accumulation of Lucifer yellow in the vacuole was used as a marker for efficient endocytosis. Fourteen mutants, including ede1Delta, rcy1Delta, sys1Delta and tlg2Delta, previously described to be involved in membrane trafficking, were identified in this screen. alpha-Factor uptake, endocytosis of FM4-64, carboxypeptidase Y secretion, vacuolar morphology, and a vma2 synthetic growth defect were used as criteria to characterize the endocytic defect of the mutant strains obtained. Accordingly, eight mutant strains have endocytic phenotypes in addition to their defect in Lucifer yellow accumulation. These fluid-phase endocytosis mutants are defective at different steps of the endocytic pathway. Interestingly, only two mutants were defective for internalization, two for vacuolar protein sorting and four mutants had aberrant vacuolar morphologies. Some of the mutants identified in this screen that sort carboxypeptidase Y correctly may affect endocytosis at an early post-internalization step before the intersection of the endocytic with the vacuolar protein-sorting pathway.
authors.affiliation: Biozentrum of the University of Basel, CH-4056 Basel, Switzerland.
authors.forename: A
authors.initials: A
authors.lastname: Wiederkehr
authors.forename: K D
authors.initials: KD
authors.lastname: Meier
authors.forename: H
authors.initials: H
authors.lastname: Riezman
mesh_terms: D002268:Carboxypeptidases / Q000378:metabolism; D043402:Cathepsin A; D004705:Endocytosis / Q000235:genetics*; D044783:F-Box Proteins; D005456:Fluorescent Dyes; D005656:Fungal Proteins / Q000235:genetics; D007546:Isoquinolines / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics; D026901:Membrane Transport Proteins; D010641:Phenotype; D010675:Pheromones / Q000378:metabolism; D017354:Point Mutation; D006180:Proton-Translocating ATPases / Q000235:genetics; D011726:Pyridinium Compounds; D050765:Qa-SNARE Proteins; D000644:Quaternary Ammonium Compounds; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D025262:Vacuolar Proton-Translocating ATPases; D014617:Vacuoles / Q000378:metabolism; D033921:Vesicular Transport Proteins
chemical_list: D044783:F-Box Proteins; C092350:FM 4-64; D005456:Fluorescent Dyes; D005656:Fungal Proteins; D007546:Isoquinolines; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D010675:Pheromones; D011726:Pyridinium Compounds; D050765:Qa-SNARE Proteins; D000644:Quaternary Ammonium Compounds; C407703:RCY1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C112252:TLG2 protein, S cerevisiae; D033921:Vesicular Transport Proteins; C017475:lucifer yellow; D002268:Carboxypeptidases; D043402:Cathepsin A; D025262:Vacuolar Proton-Translocating ATPases; D006180:Proton-Translocating ATPases