How Curved Membranes recognize Protein Anchoring Motifs - The effect of Lipid Geometry

Abstract

Previous work within the field of lipid membranes has discovered moieties able to both sense and induce the curvature of bilayers. In this thesis we use confocal fluorescent microscopy to investigate the curvature selective binding of amphipathic molecules on single liposomes. We developed a novel single liposome curvature assay, which enabled us for the first time, to quantify the binding without the ensemble averaging errors experienced for earlier methods. Surprisingly we found that the curvature selectivity did not originate from an increased affinity for the highly curved membrane, as believed by the community.

Having proven that the curvature sensing was predominantly governed by the membrane, the objective was to investigate the influence of different membrane parameters on the sensing of aklyl chains. These parameters included changing the thickness of the bilayer as well as the isomerism of the constituent lipids. Finally, we wanted to validate the curvature sensing in a highly biological relevant system, intercalating the βγ-subunit of a G-protein through a farnesyl anchor on the complex lipid mixture of brain lipid vesicles. Donig this, I was able for the first time to show that proteins with a native lipid-anchoring group are membrane curvature sensors.

Speaker

Jannik Larsen

Time and date

Thursday 18/6 at 13:15 in auditorium 10.