title: Traffic Through the Trans-Golgi Network and the Endosomal System Requires Collaboration Between Exomer and Clathrin Adaptors in Fission Yeast.
abstract: Despite its biological and medical relevance, traffic from the Golgi to the plasma membrane (PM) is one of the least understood steps of secretion. Exomer is a protein complex that mediates the trafficking of certain cargoes from the trans-Golgi network/early endosomes to the PM in budding yeast. Here, we show that in Schizosaccharomyces pombe the Cfr1 and Bch1 proteins constitute the simplest form of an exomer. Cfr1 co-immunoprecipitates with Assembly Polypeptide adaptor 1 (AP-1), AP-2, and Golgi-localized, gamma-adaptin ear domain homology, ARF-binding (GGA) subunits, and cfr1+interacts genetically with AP-1 and GGA genes. Exomer-defective cells exhibit multiple mild defects, including alterations in the morphology of Golgi stacks and the distribution of the synaptobrevin-like Syb1 protein, carboxypeptidase missorting, and stress sensitivity. S. pombe apm1Δ cells exhibit a defect in trafficking through the early endosomes that is severely aggravated in the absence of exomer. apm1Δ cfr1Δ cells exhibit a dramatic disorganization of intracellular compartments, including massive accumulation of electron-dense tubulovesicular structures. While the trans-Golgi network/early endosomes are severely disorganized in the apm1Δ cfr1Δ strain, gga21Δ gga22Δ cfr1Δ cells exhibit a significant disturbance of the prevacuolar/vacuolar compartments. Our findings show that exomer collaborates with clathrin adaptors in trafficking through diverse cellular compartments, and that this collaboration is important to maintain their integrity. These results indicate that the effect of eliminating exomer is more pervasive than that described to date, and suggest that exomer complexes might participate in diverse steps of vesicle transport in other organisms.
authors.affiliation: Department of Microbiology and Genetics, Institute of Functional Biology and Genomics (IBFG), University of Salamanca, Consejo Superior de Investigaciones Científicas (CSIC), 37007, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Hoya
authors.affiliation: Department of Microbiology and Genetics, Institute of Functional Biology and Genomics (IBFG), University of Salamanca, Consejo Superior de Investigaciones Científicas (CSIC), 37007, Spain.
authors.forename: Francisco
authors.initials: F
authors.lastname: Yanguas
authors.affiliation: Department of Microbiology and Genetics, Institute of Functional Biology and Genomics (IBFG), University of Salamanca, Consejo Superior de Investigaciones Científicas (CSIC), 37007, Spain.
authors.forename: Sandra
authors.initials: S
authors.lastname: Moro
authors.affiliation: Biozentrum, University of Basel, CH-4056, Switzerland.
authors.forename: Cristina
authors.initials: C
authors.lastname: Prescianotto-Baschong
authors.affiliation: Department of Microbiology and Genetics, Institute of Functional Biology and Genomics (IBFG), University of Salamanca, Consejo Superior de Investigaciones Científicas (CSIC), 37007, Spain.
authors.forename: Cristina
authors.initials: C
authors.lastname: Doncel
authors.affiliation: Department of Microbiology and Genetics, Institute of Functional Biology and Genomics (IBFG), University of Salamanca, Consejo Superior de Investigaciones Científicas (CSIC), 37007, Spain.
authors.forename: Nagore
authors.initials: N
authors.lastname: de León
authors.affiliation: Department of Microbiology and Genetics, Institute of Functional Biology and Genomics (IBFG), University of Salamanca, Consejo Superior de Investigaciones Científicas (CSIC), 37007, Spain.
authors.forename: M-Ángeles
authors.initials: MÁ
authors.lastname: Curto
authors.affiliation: Biozentrum, University of Basel, CH-4056, Switzerland.
authors.forename: Anne
authors.initials: A
authors.lastname: Spang
authors.affiliation: Department of Microbiology and Genetics, Institute of Functional Biology and Genomics (IBFG), University of Salamanca, Consejo Superior de Investigaciones Científicas (CSIC), 37007, Spain henar@usal.es.
authors.forename: M-Henar
authors.identifier: 0000-0002-6857-7493
authors.initials: MH
authors.lastname: Valdivieso
mesh_terms: D033961:Adaptor Protein Complex 1 / Q000235:genetics / Q000378:metabolism*; D033962:Adaptor Protein Complex 2 / Q000235:genetics / Q000378:metabolism*; D033942:Adaptor Proteins, Vesicular Transport / Q000235:genetics* / Q000378:metabolism; D011992:Endosomes / Q000378:metabolism*; D011485:Protein Binding; D021381:Protein Transport; D050683:R-SNARE Proteins / Q000235:genetics / Q000378:metabolism; D012568:Schizosaccharomyces / Q000235:genetics / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics* / Q000378:metabolism; D021601:trans-Golgi Network / Q000378:metabolism*
chemical_list: D033961:Adaptor Protein Complex 1; D033962:Adaptor Protein Complex 2; D033942:Adaptor Proteins, Vesicular Transport; D050683:R-SNARE Proteins; D029702:Schizosaccharomyces pombe Proteins; C472866:Syb1 protein, S pombe; C000619455:cfr1 protein, S pombe
keywords: Golgi; clathrin adaptors; endosomes; exomer; yeast