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ArfGAP1 generates an Arf1 gradient on continuous lipid membranes displaying flat and curved regions.
Ambroggio, Ernesto; Sorre, Benoît; Bassereau, Patricia; Goud, Bruno; Manneville, Jean-Baptiste; Antonny, Bruno.
Afiliação
  • Ambroggio E; Laboratoire Mécanismes moléculaires du transport intracellulaire, Institut Curie, CNRS UMR 144, Paris, France.
EMBO J ; 29(2): 292-303, 2010 Jan 20.
Article em En | MEDLINE | ID: mdl-19927117
ABSTRACT
ArfGAP1, which promotes GTP hydrolysis on the small G protein Arf1 on Golgi membranes, interacts preferentially with positively curved membranes through its amphipathic lipid packing sensor (ALPS) motifs. This should influence the distribution of Arf1-GTP when flat and curved regions coexist on a continuous membrane, notably during COPI vesicle budding. To test this, we pulled tubes from giant vesicles using molecular motors or optical tweezers. Arf1-GTP distributed on the giant vesicles and on the tubes, whereas ArfGAP1 bound exclusively to the tubes. Decreasing the tube radius revealed a threshold of R approximately 35 nm for the binding of ArfGAP1 ALPS motifs. Mixing catalytic amounts of ArfGAP1 with Arf1-GTP induced a smooth Arf1 gradient along the tube. This reflects that Arf1 molecules leaving the tube on GTP hydrolysis are replaced by new Arf1-GTP molecules diffusing from the giant vesicle. The characteristic length of the gradient is two orders of magnitude larger than a COPI bud, suggesting that Arf1-GTP diffusion can readily compensate for the localized loss of Arf1 during budding and contribute to the stability of the coat until fission.
Assuntos

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Fator 1 de Ribosilação do ADP / Proteínas Ativadoras de GTPase / Complexo I de Proteína do Envoltório / Lipossomas Unilamelares / Lipídeos de Membrana Idioma: En Revista: EMBO J Ano de publicação: 2010 Tipo de documento: Article País de afiliação: França

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Fator 1 de Ribosilação do ADP / Proteínas Ativadoras de GTPase / Complexo I de Proteína do Envoltório / Lipossomas Unilamelares / Lipídeos de Membrana Idioma: En Revista: EMBO J Ano de publicação: 2010 Tipo de documento: Article País de afiliação: França