title: The functional relationship between the Cdc50p-Drs2p putative aminophospholipid translocase and the Arf GAP Gcs1p in vesicle formation in the retrieval pathway from yeast early endosomes to the TGN.
abstract: Drs2p, the catalytic subunit of the Cdc50p-Drs2p putative aminophospholipid translocase, has been implicated in conjunction with the Arf1 signaling pathway in the formation of clathrin-coated vesicles (CCVs) from the TGN. Herein, we searched for Arf regulator genes whose mutations were synthetically lethal with cdc50Delta, and identified the Arf GAP gene GCS1. Most of the examined transport pathways in the Cdc50p-depleted gcs1Delta mutant were nearly normal, including endocytic transport to vacuoles, carboxypeptidase Y sorting, and the processing and secretion of invertase. In contrast, this mutant exhibited severe defects in the early endosome-to-TGN transport pathway; proteins that are transported via this pathway, such as the v-SNARE Snc1p, the t-SNARE Tlg1p, and the chitin synthase III subunit Chs3p, accumulated in TGN-independent aberrant membrane structures. We extended our analyses to clathrin adaptors, and found that Gga1p/Gga2p and AP-1 were also involved in this pathway. The Cdc50p-depleted gga1Delta gga2Delta mutant and the gcs1Delta apl2Delta (the beta1 subunit of AP-1) mutant exhibited growth defects and intracellular Snc1p-containing membranes accumulated in these cells. These results suggest that Cdc50p-Drs2p plays an important role in the Arf1p-mediated formation of CCVs for the retrieval pathway from early endosomes to the TGN.
authors.affiliation: Division of Molecular Interaction, Institute for Genetic Medicine, Hokkaido University Graduate School of Medicine, Kita-ku, Sapporo 060-0815, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Sakane
authors.forename: Takaharu
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Kazuma
authors.initials: K
authors.lastname: Tanaka
mesh_terms: D020823:ADP-Ribosylation Factor 1 / Q000235:genetics / Q000378:metabolism; D020727:ADP-Ribosylation Factors / Q000235:genetics / Q000378:metabolism; D033942:Adaptor Proteins, Vesicular Transport / Q000235:genetics / Q000378:metabolism; D000252:Calcium-Transporting ATPases / Q000235:genetics / Q000378:metabolism*; D043402:Cathepsin A / Q000378:metabolism; D002687:Chitin Synthase; D022163:Clathrin-Coated Vesicles / Q000378:metabolism* / Q000648:ultrastructure; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004705:Endocytosis / Q000502:physiology; D011992:Endosomes / Q000378:metabolism* / Q000648:ultrastructure; D005089:Exocytosis / Q000502:physiology; D020690:GTPase-Activating Proteins / Q000235:genetics / Q000378:metabolism*; D007425:Intracellular Membranes / Q000378:metabolism / Q000648:ultrastructure; D008563:Membrane Lipids / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D043484:Proprotein Convertases / Q000235:genetics / Q000378:metabolism; D050683:R-SNARE Proteins / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000378:metabolism* / Q000648:ultrastructure; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D018808:Transcription Factor AP-1 / Q000235:genetics / Q000378:metabolism; D014617:Vacuoles / Q000378:metabolism; D033921:Vesicular Transport Proteins / Q000235:genetics / Q000378:metabolism; D021601:trans-Golgi Network / Q000378:metabolism*
chemical_list: D033942:Adaptor Proteins, Vesicular Transport; C427246:CDC50 protein, S cerevisiae; D004268:DNA-Binding Proteins; C104014:DRS2 protein, S cerevisiae; C089147:GCS1 protein, S cerevisiae; D020690:GTPase-Activating Proteins; C497361:Gga2 protein, S cerevisiae; D008563:Membrane Lipids; D008565:Membrane Proteins; C087335:PEP1 protein, S cerevisiae; D050683:R-SNARE Proteins; D011993:Recombinant Fusion Proteins; C083241:SNC1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C503584:Tlg1 protein, S cerevisiae; D018808:Transcription Factor AP-1; D033921:Vesicular Transport Proteins; C069390:CHS3 protein, S cerevisiae; D002687:Chitin Synthase; D043402:Cathepsin A; D043484:Proprotein Convertases; C058751:KEX2 protein, S cerevisiae; C116686:ARF2 protein, S cerevisiae; D020823:ADP-Ribosylation Factor 1; D020727:ADP-Ribosylation Factors; D000252:Calcium-Transporting ATPases