title: Clathrin terminal domain-ligand interactions regulate sorting of mannose 6-phosphate receptors mediated by AP-1 and GGA adaptors.
abstract: Clathrin plays important roles in intracellular membrane traffic including endocytosis of plasma membrane proteins and receptors and protein sorting between the trans-Golgi network (TGN) and endosomes. Whether clathrin serves additional roles in receptor recycling, degradative sorting, or constitutive secretion has remained somewhat controversial. Here we have used acute pharmacological perturbation of clathrin terminal domain (TD) function to dissect the role of clathrin in intracellular membrane traffic. We report that internalization of major histocompatibility complex I (MHCI) is inhibited in cells depleted of clathrin or its major clathrin adaptor complex 2 (AP-2), a phenotype mimicked by application of Pitstop® inhibitors of clathrin TD function. Hence, MHCI endocytosis occurs via a clathrin/AP-2-dependent pathway. Acute perturbation of clathrin also impairs the dynamics of intracellular clathrin/adaptor complex 1 (AP-1)- or GGA (Golgi-localized, γ-ear-containing, Arf-binding protein)-coated structures at the TGN/endosomal interface, resulting in the peripheral dispersion of mannose 6-phosphate receptors. By contrast, secretory traffic of vesicular stomatitis virus G protein, recycling of internalized transferrin from endosomes, or degradation of EGF receptor proceeds unperturbed in cells with impaired clathrin TD function. These data indicate that clathrin is required for the function of AP-1- and GGA-coated carriers at the TGN but may be dispensable for outward traffic en route to the plasma membrane.
authors.affiliation: From the Leibniz-Institut für Molekulare Pharmakologie, 13125 Berlin-Buch, Germany.
authors.forename: Wiebke
authors.initials: W
authors.lastname: Stahlschmidt
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Robertson
authors.forename: Phillip J
authors.initials: PJ
authors.lastname: Robinson
authors.forename: Adam
authors.initials: A
authors.lastname: McCluskey
authors.forename: Volker
authors.initials: V
authors.lastname: Haucke
mesh_terms: D033961:Adaptor Protein Complex 1 / Q000378:metabolism*; D033962:Adaptor Protein Complex 2 / Q000378:metabolism; D033942:Adaptor Proteins, Vesicular Transport / Q000378:metabolism*; D000818:Animals; D002417:Cattle; D002966:Clathrin / Q000737:chemistry* / Q000378:metabolism*; D020755:Coat Protein Complex I / Q000378:metabolism; D003034:Coated Pits, Cell-Membrane / Q000378:metabolism; D004705:Endocytosis; D011992:Endosomes / Q000378:metabolism; D066246:ErbB Receptors / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006367:HeLa Cells; D015395:Histocompatibility Antigens Class I / Q000378:metabolism; D006801:Humans; D008562:Membrane Glycoproteins / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D017527:Receptor, IGF Type 2 / Q000378:metabolism*; D013449:Sulfonamides / Q000378:metabolism; D053778:Thiazolidines / Q000378:metabolism; D014168:Transferrin / Q000378:metabolism; D014759:Viral Envelope Proteins / Q000378:metabolism; D021601:trans-Golgi Network / Q000378:metabolism
chemical_list: D033961:Adaptor Protein Complex 1; D033962:Adaptor Protein Complex 2; D033942:Adaptor Proteins, Vesicular Transport; D002966:Clathrin; D020755:Coat Protein Complex I; C028391:G protein, vesicular stomatitis virus; C407306:GGA adaptor proteins; D015395:Histocompatibility Antigens Class I; D008562:Membrane Glycoproteins; D017527:Receptor, IGF Type 2; D013449:Sulfonamides; D053778:Thiazolidines; D014168:Transferrin; D014759:Viral Envelope Proteins; C578512:pitstop 2; D049452:Green Fluorescent Proteins; D066246:ErbB Receptors
keywords: Cell Biology; Endosomes; Lysosomes; Membrane Trafficking; Molecular Cell Biology; Protein Sorting