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Laboratory | Simulation & modelling


Structure and molecular interactions of membrane proteins

Published on 12 April 2017
The general theme of our group is dedicated to the investigation at a molecular level of interactions with proteins/lipids components of membranes using as main techniques solution/solid state NMR combined with modelisation and molecular dynamics simulations.

Nadège Jamin

Structural studies of caveolins and mechanisms of interactions at the membrane interface

Caveolin-1, a small membrane protein (21 KDa) plays a key role in the formation of caveolae defined from a morphological point of view as plasma membrane invaginations. These membrane structures are implicated in numerous cellular functions such as endocytosis, signalization, lipid transport and more recently mechanical stress. Our objective is to establish the molecular basis of the interactions networks associated with proteins and lipids in order to understand how the different networks of protein-lipid interactions are organized within these structures.

Role of S-acylation on the structure and interactions of membrane proteins with their partners (lipids/proteins)

Some membrane proteins possess acylated anchors covalently linked to cysteine. In the few cases studies of membrane proteins, it was shown that the consequences of these post-translational modifications are: protein conformational modifications, association with specific lipid domains, regulation of interactions with their partner and/or interplay with other post-translational modifications. To better understand the structural and functional role of cysteine acylation, different membrane proteins having one or more acylations are studied via complementary biochemical (production, function), biophysics (NMR) and bio-informatics (modelisation and molecular dynamics simulations) approaches.

Lateral segregation and nano-assembly of cyclodextrines at the membrane interface

Biomembranes can be viewed as a mosaic of lipid domains with unique biochemical compositions, controlled by a variety of lateral segregation processes occurring with the lipid matrix. In our group, we study the formation of phase induced by the interaction at the membrane interface of polysaccharide (cyclodextrins) inserted into lipid bilayers via an hydrophobic anchor as an example of such segregation processes. Cyclodextrins are water-soluble cyclic oligosaccharides possessing an internal rather hydrophobic cavity that can include hydrophobic compounds leading to water-soluble inclusion complexes.

Phosphatidylserine recognition and apoptosis imaging

Under standard conditions, phosphatidylserines (PS) are localized mainly in the internal leaflet of the plasma membrane. This asymmetric distribution is altered during apoptosis, and exposure of PS at the cell surface constitutes one of the early steps of this cellular process. Our objective is to develop high affinity peptide probes to PS for the in vivo detection of apoptosis. Our project is based on previous results characterizing the membrane recognition properties of annexin domains. Simultaneously, we are pursuing more fundamental studies to understand the mechanisms involved in specific interactions at the membrane interface between lipids (anionic phospholipids and sterols) and membrane-anchored protein domains.