title: Molecular mechanism of membrane recruitment of GGA by ARF in lysosomal protein transport.
abstract: GGAs are critical for trafficking soluble proteins from the trans-Golgi network (TGN) to endosomes/lysosomes through interactions with TGN-sorting receptors, ADP-ribosylation factor (ARF) and clathrin. ARF-GTP bound to TGN membranes recruits its effector GGA by binding to the GAT domain, thus facilitating recognition of GGA for cargo-loaded receptors. Here we report the X-ray crystal structures of the human GGA1-GAT domain and the complex between ARF1-GTP and the N-terminal region of the GAT domain. When unbound, the GAT domain forms an elongated bundle of three a-helices with a hydrophobic core. Structurally, this domain, combined with the preceding VHS domain, resembles CALM, an AP180 homolog involved in endocytosis. In the complex with ARF1-GTP, a helix-loop-helix of the N-terminal part of GGA1-GAT interacts with the switches 1 and 2 of ARF1 predominantly in a hydrophobic manner. These data reveal a molecular mechanism underlying membrane recruitment of adaptor proteins by ARF-GTP.
authors.affiliation: Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801, Japan.
authors.forename: Tomoo
authors.initials: T
authors.lastname: Shiba
authors.forename: Masato
authors.initials: M
authors.lastname: Kawasaki
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Takatsu
authors.forename: Terukazu
authors.initials: T
authors.lastname: Nogi
authors.forename: Naohiro
authors.initials: N
authors.lastname: Matsugaki
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Igarashi
authors.forename: Mamoru
authors.initials: M
authors.lastname: Suzuki
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Kato
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Nakayama
authors.forename: Soichi
authors.initials: S
authors.lastname: Wakatsuki
mesh_terms: D020823:ADP-Ribosylation Factor 1 / Q000737:chemistry / Q000378:metabolism; D020727:ADP-Ribosylation Factors / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D033942:Adaptor Proteins, Vesicular Transport; D000595:Amino Acid Sequence; D001665:Binding Sites; D002352:Carrier Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D002942:Circular Dichroism; D003001:Cloning, Molecular; D018360:Crystallography, X-Ray; D006160:Guanosine Triphosphate / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D008247:Lysosomes / Q000378:metabolism / Q000648:ultrastructure; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000378:metabolism; D017433:Protein Structure, Secondary; D021381:Protein Transport; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D021601:trans-Golgi Network / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D033942:Adaptor Proteins, Vesicular Transport; D002352:Carrier Proteins; C407306:GGA adaptor proteins; D010446:Peptide Fragments; D011994:Recombinant Proteins; D006160:Guanosine Triphosphate; D020823:ADP-Ribosylation Factor 1; D020727:ADP-Ribosylation Factors