title: Epsin 1 is involved in recruitment of ubiquitinated EGF receptors into clathrin-coated pits.
abstract: Epsin consists of an epsin NH(2)-terminal homology domain that promotes interaction with phospholipids, several AP-2-binding sites, two clathrin-binding sequences and several Eps15 homology domain-binding motifs. Epsin additionally possesses ubiquitin-interacting motifs (UIMs) and has been demonstrated to bind ubiquitinated cargo. We therefore investigated whether epsin promoted clathrin-mediated endocytosis of the ubiquitinated EGF receptor (EGFR). By immunoprecipitation, we found that epsin 1 interacted with ubiquitinated EGFR and that functional UIMs were essential for complex formation. Furthermore, RNA interference-mediated knockdown of epsin 1 was found to inhibit internalization of the EGFR, while having no effect on endocytosis of the transferrin receptor. Additionally, upon knockdown of epsin 1, translocation of the EGFR to central parts of clathrin-coated pits was inhibited. This supports the contention that epsin 1 promotes endocytosis of the ubiquitinated EGFR.
authors.affiliation: Institute of Pathology, University of Oslo, Rikshospitalet HF, N-0027 Oslo, Norway.
authors.forename: Maja
authors.initials: M
authors.lastname: Kazazic
authors.forename: Vibeke
authors.initials: V
authors.lastname: Bertelsen
authors.forename: Ketil Winther
authors.initials: KW
authors.lastname: Pedersen
authors.forename: Tram Thu
authors.initials: TT
authors.lastname: Vuong
authors.forename: Michael Vibo
authors.initials: MV
authors.lastname: Grandal
authors.forename: Marianne Skeie
authors.initials: MS
authors.lastname: Rødland
authors.forename: Linton M
authors.initials: LM
authors.lastname: Traub
authors.forename: Espen
authors.initials: E
authors.lastname: Stang
authors.forename: Inger Helene
authors.initials: IH
authors.lastname: Madshus
mesh_terms: D033942:Adaptor Proteins, Vesicular Transport / Q000235:genetics / Q000378:metabolism*; D020816:Amino Acid Motifs; D002460:Cell Line; D002966:Clathrin / Q000378:metabolism*; D003034:Coated Pits, Cell-Membrane / Q000378:metabolism* / Q000648:ultrastructure; D004705:Endocytosis; D066246:ErbB Receptors / Q000378:metabolism*; D006801:Humans; D008854:Microscopy, Electron; D011485:Protein Binding; D021381:Protein Transport; D034741:RNA, Small Interfering / Q000235:genetics; D011990:Receptors, Transferrin / Q000378:metabolism; D025801:Ubiquitin / Q000378:metabolism*
chemical_list: D033942:Adaptor Proteins, Vesicular Transport; D002966:Clathrin; D034741:RNA, Small Interfering; D011990:Receptors, Transferrin; D025801:Ubiquitin; C114154:epsin; D066246:ErbB Receptors