title: Crystal structure of the alpha appendage of AP-2 reveals a recruitment platform for clathrin-coat assembly.
abstract: AP-2 adaptors regulate clathrin-bud formation at the cell surface by recruiting clathrin trimers to the plasma membrane and by selecting certain membrane proteins for inclusion within the developing clathrin-coat structure. These functions are performed by discrete subunits of the adaptor heterotetramer. The carboxyl-terminal appendage of the AP-2 alpha subunit appears to regulate the translocation of several endocytic accessory proteins to the bud site. We have determined the crystal structure of the alpha appendage at 1.4-A resolution by multiwavelength anomalous diffraction phasing. It is composed of two distinct structural modules, a beta-sandwich domain and a mixed alpha-beta platform domain. Structure-based mutagenesis shows that alterations to the molecular surface of a highly conserved region on the platform domain differentially affect associations of the appendage with amphiphysin, eps15, epsin, and AP180, revealing a common protein-binding interface.
authors.affiliation: Department of Internal Medicine, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, USA.
authors.forename: L M
authors.initials: LM
authors.lastname: Traub
authors.forename: M A
authors.initials: MA
authors.lastname: Downs
authors.forename: J L
authors.initials: JL
authors.lastname: Westrich
authors.forename: D H
authors.initials: DH
authors.lastname: Fremont
mesh_terms: D033942:Adaptor Proteins, Vesicular Transport; D000595:Amino Acid Sequence; D000818:Animals; D002966:Clathrin / Q000737:chemistry / Q000378:metabolism; D018360:Crystallography, X-Ray; D006801:Humans; D046911:Macromolecular Substances; D051379:Mice; D008958:Models, Molecular; D008969:Molecular Sequence Data; D034041:Monomeric Clathrin Assembly Proteins; D016297:Mutagenesis, Site-Directed; D009419:Nerve Tissue Proteins / Q000737:chemistry* / Q000378:metabolism; D010750:Phosphoproteins / Q000737:chemistry* / Q000378:metabolism; D017433:Protein Structure, Secondary; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism
chemical_list: D033942:Adaptor Proteins, Vesicular Transport; D002966:Clathrin; D046911:Macromolecular Substances; D034041:Monomeric Clathrin Assembly Proteins; D009419:Nerve Tissue Proteins; D010750:Phosphoproteins; D011993:Recombinant Fusion Proteins; C439023:clathrin assembly protein AP180