Biophysical Society Thematic Meeting - October 13-15, 2015

Biophysics of Proteins at Surfaces: Assembly, Activation, Signaling

Thursday Speaker Abstracts

Control of Protein Adsorption and Protein-induced Membrane Deformation by Phospholipid Unsaturation Bruno Antonny . CNRS and Université de Nice Sophia Antipolis, Valbonne, France. Membrane bound organelles differ by their shape and lipid composition. Gradients of phospholipids with different fatty acid profiles are observed along the secretory pathway (endoplasmic reticulum > Golgi > plasma membrane) and in differentiated structures (e. g. axons). Using a combination of biochemical and biophysical measurements, of cell biology observations and of molecular dynamics simulations, we are exploring the role of phospholipid unsaturation on the physicochemical properties of cellular membranes. Our work reveals that membrane curvature and lipids with monounsaturated acyl chains cooperate for the formation of large lipid packing defects that can be recognized by peripheral proteins with bulky hydrophobic residues. In contrast, polyunsaturated phospholipids dampen the effect of membrane curvature on large lipid packing defects, owing to their ability to adopt various bent conformations. As a result, membrane fission is facilitated. These findings give a rationale for the high levels of monounsaturated phospholipids in membranes with biosynthetic functions (endoplasmic reticulum) and the high levels of polyunsaturated phospholipids in membranes undergoing very fast shape changes (synaptic vesicles). References: Pinot M, Vanni S, Pagnotta S, Lacas-Gervais S, Payet LA, Ferreira T, Gautier R, Goud B, Antonny B, Barelli H (2014). Polyunsaturated phospholipids facilitate membrane deformation and fission by endocytic proteins. Science 345, 693-7. Vanni S, Hirose H, Barelli H, Antonny B, Gautier R (2014). A sub-nanometre view of how membrane curvature and composition modulate lipid packing and protein recruitment. Nat Commun 5, 4916. Antonny B, Vanni S, Shindou H, Ferreira T (2015). From zero to six double bounds: phospholipid unsaturation and organelle functions. Trends in Cell Biol in press.

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