Dataset Information

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

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.

SUBMITTER: Ambroggio E

PROVIDER: S-EPMC2824456 | biostudies-literature | 2010 Jan

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

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

Ambroggio Ernesto E Sorre Benoît B Bassereau Patricia P Goud Bruno B Manneville Jean-Baptiste JB Antonny Bruno B

The EMBO journal 20091119 2

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 ...[more]

PMID: 19927117

Similar Datasets

Project description:Sabkhas are hypersaline, mineral-rich, supratidal mudflats that harbor microbes that are adapted to high salt concentration. Sabkha microbial diversity is generally studied for their community composition, but less is known about their genetic structure and heterogeneity. In this study, we analyzed a coastal sabkha for its microbial composition using 16S rDNA and whole metagenome, as well as for its population genetic structure. Our 16S rDNA analysis show high alpha diversity in both inner and edge sabkha than outer sabkha. Beta diversity result showed similar kind of microbial composition between inner and edge sabkha, while outer sabkha samples show different microbial composition. At phylum level, Bacteroidetes (~ 22 to 34%), Euryarchaeota (~ 18 to ~ 30%), unclassified bacteria (~ 24 to ~ 35%), Actinobacteria (~ 0.01 to ~ 11%) and Cyanobacteria (less than 1%) are predominantly found in both inside and edge sabkha regions, whereas Proteobacteria (~ 92 to ~ 97%) and Parcubacteria (~ 1 to ~ 2%) are predominately found in outer sabkha. Our 225 metagenomes assembly from this study showed similar bacterial community profile as observed in 16S rDNA-based analysis. From the assembled genomes, we found important genes that are involved in biogeochemical cycles and secondary metabolite biosynthesis. We observed a dynamic, thriving ecosystem that engages in metabolic activity that shapes biogeochemical structure via carbon fixation, nitrogen, and sulfur cycling. Our results show varying degrees of horizontal gene transfers (HGT) and homologous recombination, which correlates with the observed high diversity for these populations. Moreover, our pairwise population differentiation (Fst) for the abundance of species across the salinity gradient of sabkhas identified genes with strong allelic differentiation, lower diversity and elevated nonsynonymous to synonymous ratio of variants, which suggest selective sweeps for those gene variants. We conclude that the process of HGT, combined with recombination and gene specific selection, constitute the driver of genetic variation in bacterial population along a salinity gradient in the unique sabkha ecosystem.

Dataset Information

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

Publications

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

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets