title: Interaction between the triglyceride lipase ATGL and the Arf1 activator GBF1.
abstract: The Arf1 exchange factor GBF1 (Golgi Brefeldin A resistance factor 1) and its effector COPI are required for delivery of ATGL (adipose triglyceride lipase) to lipid droplets (LDs). Using yeast two hybrid, co-immunoprecipitation in mammalian cells and direct protein binding approaches, we report here that GBF1 and ATGL interact directly and in cells, through multiple contact sites on each protein. The C-terminal region of ATGL interacts with N-terminal domains of GBF1, including the catalytic Sec7 domain, but not with full-length GBF1 or its entire N-terminus. The N-terminal lipase domain of ATGL (called the patatin domain) interacts with two C-terminal domains of GBF1, HDS (Homology downstream of Sec7) 1 and HDS2. These two domains of GBF1 localize to lipid droplets when expressed alone in cells, but not to the Golgi, unlike the full-length GBF1 protein, which localizes to both. We suggest that interaction of GBF1 with ATGL may be involved in the membrane trafficking pathway mediated by GBF1, Arf1 and COPI that contributes to the localization of ATGL to lipid droplets.
authors.affiliation: Laboratoire d'Enzymologie et Biochimie Structurales, Bat 34, Centre National de la Recherche Scientifique, Gif-sur-Yvette, France.
authors.forename: Emy Njoh
authors.initials: EN
authors.lastname: Ellong
authors.forename: Krishnakant G
authors.initials: KG
authors.lastname: Soni
authors.forename: Quynh-Trang
authors.initials: QT
authors.lastname: Bui
authors.forename: Rachid
authors.initials: R
authors.lastname: Sougrat
authors.forename: Marie-Pierre
authors.initials: MP
authors.lastname: Golinelli-Cohen
authors.forename: Catherine L
authors.initials: CL
authors.lastname: Jackson
mesh_terms: D020823:ADP-Ribosylation Factor 1 / Q000737:chemistry / Q000378:metabolism*; D055162:Biocatalysis; D020662:Guanine Nucleotide Exchange Factors / Q000737:chemistry / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D047468:Immunoprecipitation; D008049:Lipase / Q000737:chemistry / Q000378:metabolism*; D008055:Lipids; D016253:Microscopy, Immunoelectron; D011485:Protein Binding; D025941:Protein Interaction Mapping; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D020798:Two-Hybrid System Techniques; D000217:Acyltransferases
chemical_list: D020823:ADP-Ribosylation Factor 1; D020662:Guanine Nucleotide Exchange Factors; D008049:Lipase; D008055:Lipids; C120445:GBF1 protein, human; C494794:PNPLA2 protein, human; D000217:Acyltransferases