title: FYVE-dependent endosomal targeting of an arrestin-related protein in amoeba.
abstract: BACKGROUND
  Visual and β-arrestins are scaffolding proteins involved in the regulation of receptor-dependent intracellular signaling and their trafficking. The arrestin superfamilly includes several arrestin domain-containing proteins and the structurally related protein Vps26. In Dictyostelium discoideum, the arrestin-domain containing proteins form a family of six members, namely AdcA to -F. In contrast to canonical arrestins, Dictyostelium Adc proteins show a more complex architecture, as they possess, in addition to the arrestin core, other domains, such as C2, FYVE, LIM, MIT and SAM, which potentially mediate selective interactions with either lipids or proteins.
  
  
  RESULTS
  A detailed analysis of AdcA has been performed. AdcA extends on both sides of the arrestin core, in particular by a FYVE domain which mediates selective interactions with PI(3)P, as disclosed by intrinsic fluorescence measurements and lipid overlay assays. Localization studies showed an enrichment of tagged- and endogenous AdcA on the rim of early macropinosomes and phagosomes. This vesicular distribution relies on a functional FYVE domain. Our data also show that the arrestin core binds the ADP-ribosylation factor ArfA, the unique amoebal Arf member, in its GDP-bound conformation.
  
  
  CONCLUSIONS
  This work describes one of the 6 arrestin domain-containing proteins of Dictyostelium, a novel and atypical member of the arrestin clan. It provides the basis for a better understanding of arrestin-related protein involvement in trafficking processes and for further studies on the expanding roles of arrestins in eukaryotes.
authors.affiliation: CEA, DSV, iRTSV, Laboratoire de Biochimie et Biophysique des Systèmes Intégrés, Grenoble, France.
authors.forename: Dorian
authors.initials: D
authors.lastname: Guetta
authors.forename: Karine
authors.initials: K
authors.lastname: Langou
authors.forename: Didier
authors.initials: D
authors.lastname: Grunwald
authors.forename: Gérard
authors.initials: G
authors.lastname: Klein
authors.forename: Laurence
authors.initials: L
authors.lastname: Aubry
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry; D019393:Arrestin / Q000737:chemistry* / Q000302:isolation & purification; D004023:Dictyostelium; D011992:Endosomes / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000737:chemistry; D008055:Lipids / Q000737:chemistry; D051379:Mice; D008856:Microscopy, Fluorescence / Q000379:methods; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D011817:Rabbits; D017386:Sequence Homology, Amino Acid; D013347:Subcellular Fractions
chemical_list: D000911:Antibodies, Monoclonal; D019393:Arrestin; D008055:Lipids; D049452:Green Fluorescent Proteins