ANTONNY , Bruno

Bacteria and eukaryotic cells contain geometry-sensing tools in their cytosol: protein motifs or domains that recognize the curvature, concave or convex, deep or shallow, of lipid membranes. These sensors contrast with classical lipid-binding domains by their extended structure and, sometimes, counterintuitive chemistry. Among the sensors are...

Cholesterol is synthesized in the endoplasmic reticulum (RE) and then transported to cellular compartments whose functions require high cholesterol levels. Here, we describe the mechanism by which cholesterol is transported from the RE to the trans-Golgi network (TGN) by the protein OSBP (Oxysterol-Binding Protein). OSBP has two complementary...

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Numerous data have been collected on lipid-binding amphipathic helices involved in membrane-remodeling machineries and vesicular transport. Here we describe how, with regard to lipid composition, the physicochemical features of some amphipathic helices explain their ability to recognize membrane curvature or to participate in membrane...

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During membrane fission, the GTPase dynamin forms helical assemblies at the neck of membrane buds. Although it has been proposed that fission results from the constriction of the dynamin helix, new work by Bashkirov et al. (2008) and Pucadyil and Schmid (2008) unexpectedly shows that helix disassembly is also necessary for membrane fission.

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Many cellular processes require membrane deformation, which is driven by specialized protein machinery and can often be recapitulated using pure lipid bilayers. However, biological membranes contain a large amount of embedded proteins. Recent research suggests that membrane-bound proteins with asymmetric distribution of mass across the bilayer...

When the binding of one ligand to its receptor is influenced by a second ligand acting on a different receptor, one might assume that the receptors dimerize, enabling allosteric interactions between ligands. This reasoning is frequently used to explain the complex binding curves of ligands of class A G-protein-coupled receptors (GPCRs). Here,...

A cellular membrane is highly deformable: during the last decade, numerous studies have dissected at the molecular scale how during vesicular transport various proteins could deform a membrane or recognize membrane deformation. We will discuss how the activity of ArfGAP1 and GMAP-210, two proteins involved in vesicular transport, is regulated...

In the cell, membrane deformation and fission (collectively refered as to 'budding') is driven by specific protein machineries but is also influenced by lipid composition. We previously reported that phospholipids with polyunsaturated acyl chains facilitate membrane budding because they adapt their shape to membrane curvature, thereby...

Many cellular processes require membrane deformation, which is driven by specialized protein machinery and can often be recapitulated using pure lipid bilayers. However, biological membranes contain a large amount of embedded proteins. Recent research suggests that membrane-bound proteins with asymmetric distribution of mass across the bilayer...

International audience

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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...

SUMMARY: HELIQUEST calculates the physicochemical properties and amino acid composition of an alpha -helix and screens databank to identify protein segments possessing similar features. This server is also dedicated to mutating helices manually or automatically by genetic algorithm to design analogues of defined features. AVAILABILITY:...

Some mammalian cells show striking differences in the acyl chain composition of their membrane phospholipids. In most cases, the majority of phospholipids bear one saturated and one monounsaturated acyl chains at positions 1 and 2 or the glycerol, respectively. However, some cells and notably neurons contain large amounts of phospholipids with...

Some mammalian cells show striking differences in the acyl chain composition of their membrane phospholipids. In most cases, the majority of phospholipids bear one saturated and one monounsaturated acyl chains at positions 1 and 2 or the glycerol, respectively. However, some cells and notably neurons contain large amounts of phospholipids with...

ArfGAP1 (Arf GTPase activating protein 1) controls the cycling of the COPI coat on Golgi membranes by catalyzing GTP hydrolysis in the small G protein Arf1. ArfGAP1 contains a central motif named ALPS (ArfGAP1 lipid-packing sensor) that adsorbs preferentially onto highly curved membranes. This motif allows coupling of the rate of GTP hydrolysis...

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Guanine nucleotide exchange factors (GEFs) are essential regulators of the spatiotemporal conditions of small GTP-binding protein (SMG) activation. Their cellular activities combine the biochemical stimulation of GDP/GTP exchange, which leads to the active conformation of the SMG, to the detection of upstream signals and, in some cases,...

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