The Experts below are selected from a list of 5739 Experts worldwide ranked by ideXlab platform

Felix T. Wieland - One of the best experts on this subject based on the ideXlab platform.

  • 9Å structure of the COPI coat reveals that the Arf1 GTPase occupies two contrasting molecular environments.
    eLife, 2017
    Co-Authors: S.o. Dodonova, P. Aderhold, J. Kopp, Iva Ganeva, Simone Röhling, Wim J. H. Hagen, Irmgard Sinning, Felix T. Wieland, John A. G. Briggs
    Abstract:

    COPI coated Vesicles mediate trafficking within the Golgi apparatus and between the Golgi and the endoplasmic reticulum. Assembly of a COPI coated Vesicle is initiated by the small GTPase Arf1 that recruits the coatomer complex to the membrane, triggering polymerization and budding. The Vesicle uncoats before fusion with a target membrane. Coat components are structurally conserved between COPI and clathrin/adaptor proteins. Using cryo-electron tomography and subtomogram averaging, we determined the structure of the COPI coat assembled on membranes in vitro at 9 A resolution. We also obtained a 2.57 A resolution crystal structure of βδ-COP. By combining these structures we built a molecular model of the coat. We additionally determined the coat structure in the presence of ArfGAP proteins that regulate coat dissociation. We found that Arf1 occupies contrasting molecular environments within the coat, leading us to hypothesize that some Arf1 molecules may regulate Vesicle assembly while others regulate coat disassembly.

  • structure of the cytoplasmic domain of p23 in solution implications for the formation of copi Vesicles
    Biochemical and Biophysical Research Communications, 2000
    Co-Authors: Marcus Weidler, Felix T. Wieland, Constanze Reinhard, Gabi Friedrich, Paul Rosch
    Abstract:

    Abstract Coatomer, the coat protein complex of coat protein (COPI) Vesicles, is involved in the budding of these Vesicles. Its interaction with the cytoplasmic domains of some p24-family members, type I transmembrane proteins of the Golgi, has been shown to induce a conformational change of coatomer that initiates polymerization of the complex. From stoichiometrical data it is likely that interaction of coatomer with the small tail domains involves an oligomeric form of the p24 proteins. Here we present the structure of peptide analogs of the cytoplasmic domain of p23, a member of the p24 family, as determined by two-dimensional nuclear magnetic resonance spectroscopy in the presence of 2,2,2-trifluoroethanol. An improved strategy for structure calculation revealed that the tail domain peptides form α-helices and adopt a tetrameric state. Based on these results we propose an initial model for the binding of coatomer by p23 and the induced conformational change of coatomer that results in its polymerization, curvature of the Golgi membrane to form a bud, and finally a COPI-coated Vesicle.

  • a role for adp ribosylation factor in the control of cargo uptake during copi coated Vesicle biogenesis
    FEBS Letters, 1999
    Co-Authors: Jo Rg Malsam, Felix T. Wieland, Daniel U Gommel, Walter Nickel
    Abstract:

    ARF-mediated hydrolysis of GTP has been demonstrated to regulate coat disassembly of Golgi-derived COPI transport Vesicles (Tanigawa, G., Orci, L., Amherdt, M., Ravazzola, M., Helms, J.B. and Rothman, J.E. (1993) J. Cell Biol. 123, 1365–1371). In addition, a requirement for GTP hydrolysis at an early stage of COPI Vesicle biogenesis has been established since cargo uptake is impaired in the presence of GTPγS (Nickel, W., Malsam, J., Gorgas, K., Ravazzola, M., Jenne, N., Helms, J.B. and Wieland, F.T. (1998) J. Cell Sci. 111, 3081–3090), a non-hydrolyzable analogue of GTP. We now demonstrate that the GTPase involved in the regulation of cargo uptake is ARF, revealing a multi-functional role of this GTPase in COPI-mediated vesicular transport. The molecular mechanism of cargo uptake as well as the functional implications of these findings on the overall process of COPI Vesicle biogenesis are discussed.

John A. G. Briggs - One of the best experts on this subject based on the ideXlab platform.

  • 9Å structure of the COPI coat reveals that the Arf1 GTPase occupies two contrasting molecular environments.
    eLife, 2017
    Co-Authors: S.o. Dodonova, P. Aderhold, J. Kopp, Iva Ganeva, Simone Röhling, Wim J. H. Hagen, Irmgard Sinning, Felix T. Wieland, John A. G. Briggs
    Abstract:

    COPI coated Vesicles mediate trafficking within the Golgi apparatus and between the Golgi and the endoplasmic reticulum. Assembly of a COPI coated Vesicle is initiated by the small GTPase Arf1 that recruits the coatomer complex to the membrane, triggering polymerization and budding. The Vesicle uncoats before fusion with a target membrane. Coat components are structurally conserved between COPI and clathrin/adaptor proteins. Using cryo-electron tomography and subtomogram averaging, we determined the structure of the COPI coat assembled on membranes in vitro at 9 A resolution. We also obtained a 2.57 A resolution crystal structure of βδ-COP. By combining these structures we built a molecular model of the coat. We additionally determined the coat structure in the presence of ArfGAP proteins that regulate coat dissociation. We found that Arf1 occupies contrasting molecular environments within the coat, leading us to hypothesize that some Arf1 molecules may regulate Vesicle assembly while others regulate coat disassembly.

S.o. Dodonova - One of the best experts on this subject based on the ideXlab platform.

  • 9Å structure of the COPI coat reveals that the Arf1 GTPase occupies two contrasting molecular environments.
    eLife, 2017
    Co-Authors: S.o. Dodonova, P. Aderhold, J. Kopp, Iva Ganeva, Simone Röhling, Wim J. H. Hagen, Irmgard Sinning, Felix T. Wieland, John A. G. Briggs
    Abstract:

    COPI coated Vesicles mediate trafficking within the Golgi apparatus and between the Golgi and the endoplasmic reticulum. Assembly of a COPI coated Vesicle is initiated by the small GTPase Arf1 that recruits the coatomer complex to the membrane, triggering polymerization and budding. The Vesicle uncoats before fusion with a target membrane. Coat components are structurally conserved between COPI and clathrin/adaptor proteins. Using cryo-electron tomography and subtomogram averaging, we determined the structure of the COPI coat assembled on membranes in vitro at 9 A resolution. We also obtained a 2.57 A resolution crystal structure of βδ-COP. By combining these structures we built a molecular model of the coat. We additionally determined the coat structure in the presence of ArfGAP proteins that regulate coat dissociation. We found that Arf1 occupies contrasting molecular environments within the coat, leading us to hypothesize that some Arf1 molecules may regulate Vesicle assembly while others regulate coat disassembly.

P. Aderhold - One of the best experts on this subject based on the ideXlab platform.

  • 9Å structure of the COPI coat reveals that the Arf1 GTPase occupies two contrasting molecular environments.
    eLife, 2017
    Co-Authors: S.o. Dodonova, P. Aderhold, J. Kopp, Iva Ganeva, Simone Röhling, Wim J. H. Hagen, Irmgard Sinning, Felix T. Wieland, John A. G. Briggs
    Abstract:

    COPI coated Vesicles mediate trafficking within the Golgi apparatus and between the Golgi and the endoplasmic reticulum. Assembly of a COPI coated Vesicle is initiated by the small GTPase Arf1 that recruits the coatomer complex to the membrane, triggering polymerization and budding. The Vesicle uncoats before fusion with a target membrane. Coat components are structurally conserved between COPI and clathrin/adaptor proteins. Using cryo-electron tomography and subtomogram averaging, we determined the structure of the COPI coat assembled on membranes in vitro at 9 A resolution. We also obtained a 2.57 A resolution crystal structure of βδ-COP. By combining these structures we built a molecular model of the coat. We additionally determined the coat structure in the presence of ArfGAP proteins that regulate coat dissociation. We found that Arf1 occupies contrasting molecular environments within the coat, leading us to hypothesize that some Arf1 molecules may regulate Vesicle assembly while others regulate coat disassembly.

J. Kopp - One of the best experts on this subject based on the ideXlab platform.

  • 9Å structure of the COPI coat reveals that the Arf1 GTPase occupies two contrasting molecular environments.
    eLife, 2017
    Co-Authors: S.o. Dodonova, P. Aderhold, J. Kopp, Iva Ganeva, Simone Röhling, Wim J. H. Hagen, Irmgard Sinning, Felix T. Wieland, John A. G. Briggs
    Abstract:

    COPI coated Vesicles mediate trafficking within the Golgi apparatus and between the Golgi and the endoplasmic reticulum. Assembly of a COPI coated Vesicle is initiated by the small GTPase Arf1 that recruits the coatomer complex to the membrane, triggering polymerization and budding. The Vesicle uncoats before fusion with a target membrane. Coat components are structurally conserved between COPI and clathrin/adaptor proteins. Using cryo-electron tomography and subtomogram averaging, we determined the structure of the COPI coat assembled on membranes in vitro at 9 A resolution. We also obtained a 2.57 A resolution crystal structure of βδ-COP. By combining these structures we built a molecular model of the coat. We additionally determined the coat structure in the presence of ArfGAP proteins that regulate coat dissociation. We found that Arf1 occupies contrasting molecular environments within the coat, leading us to hypothesize that some Arf1 molecules may regulate Vesicle assembly while others regulate coat disassembly.