title: Oligomeric Dop1p is part of the endosomal Neo1p-Ysl2p-Arl1p membrane remodeling complex.
abstract: Yeast Dop1p is an essential protein that is highly conserved in evolution and whose function is largely unknown. Here, we provide evidence that Dop1p localizes to endosomes and exists in a complex with two other conserved proteins: Neo1p, a P(4)-ATPase and putative flippase, and the scaffolding protein Ysl2p/Mon2p. The latter operates during membrane budding at the tubular endosomal network/trans-Golgi network (TEN/TGN) in a process that includes clathrin recruitment via adaptor proteins. Consistent with a role for Dop1p during this process, temperature-sensitive dop1-3 cells accumulate multivesicular, elongated tubular and ring-like structures similar to those displayed by neo1 and ysl2 mutants. In further agreement with the concept of Dop1p-Neo1p-Ysl2p complex formation and co-operation, we show that dop1-3 cells exhibit reduced levels of Neo1p and Ysl2p at steady state. Conversely, mutations or deletions in NEO1 and YSL2 lead to a decrease in Dop1p levels. In addition to binding to Neo1p and Ysl2p, Dop1p can form dimers or multimers. A critical region for dimerization resides in the C-terminus with leucine zipper-like domains. Dop1p's membrane association is largely mediated by its internal region, but Ysl2p might not be crucial for membrane recruitment.
authors.affiliation: University of Stuttgart, Institute for Biochemistry, D-70569 Stuttgart, Germany.
authors.forename: Sónia
authors.initials: S
authors.lastname: Barbosa
authors.forename: Dagmar
authors.initials: D
authors.lastname: Pratte
authors.forename: Heinz
authors.initials: H
authors.lastname: Schwarz
authors.forename: Rüdiger
authors.initials: R
authors.lastname: Pipkorn
authors.forename: Birgit
authors.initials: B
authors.lastname: Singer-Krüger
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism; D011992:Endosomes / Q000737:chemistry / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D007425:Intracellular Membranes / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D020559:Monomeric GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D046912:Multiprotein Complexes / Q000737:chemistry / Q000378:metabolism; D009154:Mutation; D049294:Phospholipid Transfer Proteins; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D033921:Vesicular Transport Proteins / Q000235:genetics / Q000378:metabolism*; D021601:trans-Golgi Network / Q000378:metabolism
chemical_list: C427246:CDC50 protein, S cerevisiae; C508366:Dop1 protein, S cerevisiae; C507257:MON2 protein, S cerevisiae; D026901:Membrane Transport Proteins; D046912:Multiprotein Complexes; D049294:Phospholipid Transfer Proteins; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D033921:Vesicular Transport Proteins; C487039:ARL1 protein, S cerevisiae; D000251:Adenosine Triphosphatases; D020559:Monomeric GTP-Binding Proteins; C104013:NEO1 protein, S cerevisiae