title: Phosphoinositide-mediated clathrin adaptor progression at the trans-Golgi network.
abstract: Clathrin-coated vesicles mediate endocytosis and transport between the trans-Golgi network (TGN) and endosomes in eukaryotic cells. Clathrin adaptors play central roles in coat assembly, interacting with clathrin, cargo and membranes. Two main types of clathrin adaptor act in TGN-endosome traffic: GGA proteins and the AP-1 complex. Here we characterize the relationship between GGA proteins, AP-1 and other TGN clathrin adaptors using live-cell and super-resolution microscopy in yeast. We present evidence that GGA proteins and AP-1 are recruited sequentially in two waves of coat assembly at the TGN. Mutations that decrease phosphatidylinositol 4-phosphate (PtdIns(4)P) levels at the TGN slow or uncouple AP-1 coat assembly from GGA coat assembly. Conversely, enhanced PtdIns(4)P synthesis shortens the time between adaptor waves. Gga2p binds directly to the TGN PtdIns(4)-kinase Pik1p and contributes to Pik1p recruitment. These results identify a PtdIns(4)P-based mechanism for regulating progressive assembly of adaptor-specific clathrin coats at the TGN.
authors.affiliation: Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, California 90095, USA.
authors.forename: Lydia
authors.initials: L
authors.lastname: Daboussi
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Costaguta
authors.forename: Gregory S
authors.initials: GS
authors.lastname: Payne
mesh_terms: D019870:1-Phosphatidylinositol 4-Kinase / Q000235:genetics / Q000378:metabolism*; D033961:Adaptor Protein Complex 1 / Q000235:genetics / Q000378:metabolism; D033942:Adaptor Proteins, Vesicular Transport / Q000235:genetics / Q000378:metabolism*; D002966:Clathrin / Q000378:metabolism; D022163:Clathrin-Coated Vesicles / Q000378:metabolism; D011992:Endosomes / Q000378:metabolism; D015151:Immunoblotting; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D009154:Mutation; D018129:Phosphatidylinositol Phosphates / Q000378:metabolism*; D011485:Protein Binding; D021381:Protein Transport; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D059008:Time-Lapse Imaging; D021601:trans-Golgi Network / Q000378:metabolism*
chemical_list: D033961:Adaptor Protein Complex 1; D033942:Adaptor Proteins, Vesicular Transport; D002966:Clathrin; C497361:Gga2 protein, S cerevisiae; D008164:Luminescent Proteins; D018129:Phosphatidylinositol Phosphates; D029701:Saccharomyces cerevisiae Proteins; C037178:phosphatidylinositol 4-phosphate; D019870:1-Phosphatidylinositol 4-Kinase; C441760:PIK1 protein, S cerevisiae