Interactions physiques de bicouches lipidiques déposées sur un coussin de polymères pour l'incorporation de protéines

Physical interactions of cushioned supported lipid bilayers for protein incorporation

• Auteur / Autrice : Jean Goder
• Direction : Éric Perez
• Type : Projet de thèse
• Discipline(s) : Physique
• Date : Inscription en doctorat le 01/09/2016; Soutenance le 18/12/2019
• Etablissement(s) : Paris Sciences et Lettres (ComUE)
• Ecole(s) doctorale(s) : École doctorale Physique en Île-de-France (Paris ; 2014-....)
• Partenaire(s) de recherche : Laboratoire : LABORATOIRE DE PHYSIQUE STATISTIQUE DE L'E.N.S.
• Partenaire(s) de recherche : établissement de préparation de la thèse : École normale supérieure (Paris ; 1985-....)

Mots clés

Mots clés libres

Membranes protéinées

Supports membranaires

Mesures de forces en surface

Coussin de polymères

Membranes proteins

Supported membranes

Surface forces measurements

Cushioned supported

Résumé

Ce projet vise à préparer des membranes soutenues qui contiennent des protéines incorporé de la bonne façon dans une matrice lipidique et les utiliser dans des études pertinentes sur le plan biologique impliquant des interactions membranaires et de fusion.

Incorporating membrane proteins into supported membranes for surface forces measurements Supported lipid membranes on solid surfaces have been used for many years to examine the fundamental physical interactions between lipid bilayers (electrostatic, hydration, hydrophobic, van der Waals), and as primitive imitations of the cell membrane surface. Single or multi-component lipid membranes are easily prepared by adsorption of vesicles or Langmuir-Blodgett film deposition on flat, solid surfaces. However, these methods are not suitable for addressing problems involving membranes with lipids and transmembrane proteins because such proteins inevitably denature due to unfavorable interactions with the solid surface. This project aims to prepare suitable supported membranes that contain proteins incorporated the right way in the lipid matrix and use them in biologically relevant studies involving membrane interactions and fusion. To prepare surfaces with biochemically-active membrane proteins, a thin (~5-10 nm) hydrophilic polymer layer is needed to act as a hydrated “spacer” between the solid surface and the membrane. In this experimental project, the student will develop self-assembly chemistry to prepare polymer scaffolds, followed by vesicle adsorption to create supported, tethered, and cushioned biomembranes. Different types of polymers and film compositions will be tested to optimize the vesicle adsorption, membrane structure, and protein activity. The main objective of the first stage of the project is to develop a facile synthesis procedure that results in a stable membrane incorporated with active proteins. The second stage of the project will involve using the developed membrane surfaces to simulate biological processes in the surface forces apparatus (SFA). The SFA technique involves mounting membranes on solid surfaces (generally mica) and then measuring the interaction forces between the membranes. The cushioned surfaces will provide a membrane surface that is closer to its native state, allowing for membrane proteins to be incorporated. Initially SNARE proteins will be examined, and the developed methods are expected to allow membrane interactions, deformations, and fusion induced by the SNARE protein machinery to be measured for the first time. Other membrane proteins will subsequently be examined, for example, G-protein coupled receptor (GPCR) proteins that influence physiological signaling pathways.