ArfGAP1 generates an Arf1 gradient on continuous lipid membranes displaying flat and curved regions.
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.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Fator 1 de Ribosilação do ADP
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Proteínas Ativadoras de GTPase
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Complexo I de Proteína do Envoltório
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Lipossomas Unilamelares
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Lipídeos de Membrana
Idioma:
En
Revista:
EMBO J
Ano de publicação:
2010
Tipo de documento:
Article
País de afiliação:
França