title: Btn3 regulates the endosomal sorting function of the yeast Ent3 epsin, an adaptor for SNARE proteins.
abstract: Ent3 and Ent5 are yeast epsin N-terminal homology (ENTH) domain-containing proteins involved in protein trafficking between the Golgi and late endosomes. They interact with clathrin, clathrin adaptors at the Golgi (AP-1 and GGA) and different SNAREs (Vti1, Snc1, Pep12 and Syn8) required for vesicular transport at the Golgi and endosomes. To better understand the role of these epsins in membrane trafficking, we performed a protein-protein interaction screen. We identified Btn3 (also known as Tda3), a putative oxidoreductase, as a new partner of both Ent3 and Ent5. Btn3 is a negative regulator of the Batten-disease-linked protein Btn2 involved in the retrieval of specific SNAREs (Vti1, Snc1, Tlg1 and Tlg2) from the late endosome to the Golgi. We show that Btn3 endosomal localization depends on the epsins Ent3 and Ent5. We demonstrated that in btn3Δ mutant cells, endosomal sorting of ubiquitylated cargos and endosomal recycling of the Snc1 SNARE are delayed. We thus propose that Btn3 regulates the sorting function of two adaptors for SNARE proteins, the epsin Ent3 and the Batten-disease-linked protein Btn2.
authors.affiliation: Department of Molecular and Cellular Genetics, UMR7156, Centre National de Recherche Scientifique (CNRS), Université de Strasbourg, Strasbourg 67084, France.
authors.forename: Joëlle
authors.initials: J
authors.lastname: Morvan
authors.affiliation: Department of Molecular and Cellular Genetics, UMR7156, Centre National de Recherche Scientifique (CNRS), Université de Strasbourg, Strasbourg 67084, France.
authors.forename: Johan-Owen
authors.initials: JO
authors.lastname: de Craene
authors.affiliation: Department of Molecular and Cellular Genetics, UMR7156, Centre National de Recherche Scientifique (CNRS), Université de Strasbourg, Strasbourg 67084, France.
authors.forename: Bruno
authors.initials: B
authors.lastname: Rinaldi
authors.affiliation: Department of Molecular and Cellular Genetics, UMR7156, Centre National de Recherche Scientifique (CNRS), Université de Strasbourg, Strasbourg 67084, France.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Addis
authors.affiliation: Department of Molecular and Cellular Genetics, UMR7156, Centre National de Recherche Scientifique (CNRS), Université de Strasbourg, Strasbourg 67084, France.
authors.forename: Cédric
authors.initials: C
authors.lastname: Misslin
authors.affiliation: Department of Molecular and Cellular Genetics, UMR7156, Centre National de Recherche Scientifique (CNRS), Université de Strasbourg, Strasbourg 67084, France s.friant@unistra.fr.
authors.forename: Sylvie
authors.initials: S
authors.lastname: Friant
mesh_terms: D033942:Adaptor Proteins, Vesicular Transport / Q000235:genetics / Q000378:metabolism*; D026905:Amino Acid Transport Systems / Q000235:genetics / Q000378:metabolism*; D011992:Endosomes / Q000378:metabolism*; D006056:Golgi Apparatus / Q000378:metabolism; D040081:Protein Array Analysis; D025941:Protein Interaction Mapping; D021381:Protein Transport / Q000502:physiology; D050600:SNARE Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D033921:Vesicular Transport Proteins / Q000235:genetics / Q000378:metabolism*; D050888:Heat-Shock Proteins, Small
chemical_list: D033942:Adaptor Proteins, Vesicular Transport; D026905:Amino Acid Transport Systems; D050600:SNARE Proteins; D029701:Saccharomyces cerevisiae Proteins; D033921:Vesicular Transport Proteins; C473804:BTN2 protein, S cerevisiae; D050888:Heat-Shock Proteins, Small; C495587:Ent3 protein, S cerevisiae; C495588:Ent5 protein, S cerevisiae; C560786:TDA3 protein, S cerevisiae; C114154:epsin
keywords: ESCRT; Epsin; Multivesicular body; Ubiquitin; Yeast