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Article Dans Une Revue EMBO Journal Année : 2010

ArfGAP1 generates an Arf1 gradient on continuous lipid membranes displaying flat and curved regions.

Résumé

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.

Dates et versions

hal-00497638 , version 1 (05-07-2010)

Identifiants

Citer

Ernesto Ambroggio, Benoît Sorre, Patricia Bassereau, Bruno Goud, Jean-Baptiste Manneville, et al.. ArfGAP1 generates an Arf1 gradient on continuous lipid membranes displaying flat and curved regions.. EMBO Journal, 2010, 29 (2), pp.292-303. ⟨10.1038/emboj.2009.341⟩. ⟨hal-00497638⟩
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