title: ARL1 plays a role in the binding of the GRIP domain of a peripheral matrix protein to the Golgi apparatus in plant cells.
abstract: ARF GTPases play a central role in regulating membrane dynamics and protein transport in eukaryotic cells. ARF-like (ARL) proteins are close relatives of the ARF regulators of vesicular transport, but their function in plant cells is poorly characterized. Here, by means of live cell imaging and site-directed mutagenesis, we have investigated the cellular function of the plant GTPase ARL1. We provide direct evidence for a role of this ARL family member in the association of a plant golgin with the plant Golgi apparatus. Our data reveal the existence of key residues within the conserved GRIP-domain of the golgin and within the GTPase ARL1 that are central to ARL1-GRIP interaction. Mutations of these residues abolish the interaction of GRIP with the GTP-bound ARL1 and induce a redistribution of GRIP into the cytosol. This indicates that the localization of GRIP to the Golgi apparatus is strongly influenced by the interaction of GRIP with Golgi-localized ARL1. Our results assign a cellular role to a member of the Arabidopsis ARL family in the plant secretory pathway and propose mechanisms for localization of peripheral golgins to the plant Golgi apparatus.
authors.affiliation: Department of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, S7N 5E2, SK, Canada.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Stefano
authors.forename: Luciana
authors.initials: L
authors.lastname: Renna
authors.forename: Sally L
authors.initials: SL
authors.lastname: Hanton
authors.forename: Laurent
authors.initials: L
authors.lastname: Chatre
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Haas
authors.forename: Federica
authors.initials: F
authors.lastname: Brandizzi
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000596:Amino Acids / Q000737:chemistry / Q000502:physiology; D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000032:analysis / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D001665:Binding Sites; D006056:Golgi Apparatus / Q000378:metabolism* / Q000648:ultrastructure; D008565:Membrane Proteins / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D017434:Protein Structure, Tertiary; D021381:Protein Transport / Q000502:physiology; D011993:Recombinant Fusion Proteins / Q000032:analysis; D016415:Sequence Alignment
chemical_list: C513532:ARL1 (ARF-like) protein, Arabidopsis; D000596:Amino Acids; D029681:Arabidopsis Proteins; C496228:GRIP protein, Arabidopsis; D008565:Membrane Proteins; D011993:Recombinant Fusion Proteins