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Home > Departments > Biochemistry, Biophysics and Structural Biology > Francis HARAUX : Membrane Proteins and Membrane Systems Laboratory

Francis HARAUX : Group Presentation

The LPSM studies membrane proteins and membrane systems at different complexity levels, from molecules to cells, using biochemical and biophysical techniques. Investigations include structure, mechanism and regulation of membrane-associated proteins, the role of lipids and membrane environment, and possible diagnostic and therapeutic applications.

The Membrane Proteins and Membrane Systems Laboratory (LPSM) gathers researchers, engineers, technicians and students working on several aspects of membranes and membrane proteins, including transport processes, cell signaling, cell detoxification and bioenergetics.
Some projects (Ca2+-ATPase, ATP synthase or other mitochondrial complexes, lipid translocases or “flippases”, P-glycoprotein (P-gp)) aim at determining detailed enzymatic mechanisms through structure/function studies, and analyzing regulations.
Other projects (MRP1, flippases, caveolins, annexins) deal with the understanding, at a molecular/atomic level, of the specific interactions between membrane lipids and proteins. To reach these goals, we develop molecular biology and biochemistry approaches, combined with many analytical techniques including enzyme kinetics, proteomics and biophysical techniques (fluorimetry, circular dichroism, molecular dynamics simulations, NMR, crystallography). These expertises are also a source of several collaborative projects, for instance for the characterization of other membrane proteins and for the imaging of apoptosis. We have the expertise to produce and purify all the proteins we are working on.

LPSM

Several P-type ATPases (mammalian Ca2+-ATPase, P. falciparum Ca2+-ATPase, S. cerevisiae Drs2p, other putative flippases) and several multidrug resistance ATPases (MRP1, P-gp, PfCRT, PfMDR1) are currently studied at the LPSM, with the double objective of deciphering basic mechanisms and developing drugs against some of them for therapeutic use.

Among our investigations of biological membrane properties, one may mention the study of membrane asymmetry. Two main questions are addressed: how phosphatidylserine molecules are translocated by flippases, and how they are recognized near the membrane interface by molecules like annexin. The second aspect helps developing molecules for cell death imaging and for targeting apoptotic cells.

Regulatory processes are also extensively studied at the LPSM. Our investigations include interaction of proteins with regulatory peptides (Ca2+-ATPase - sarcolipin, Drs2p - Cdc50p, ATP synthase - IF1), and post-traductional modifications of some enzymes and of their regulatory peptides, as well as the possible interference between the transport of membrane lipids and of hydrophobic substrates.

Keywords

Biomembranes, Membrane proteins, Enzyme structure, Enzyme mechanism, Transport, Biophysics, Bioenergetics, ATPases, Protein-protein interactions, Lipid-protein interactions

Contact


HARAUX Francis [Senior Researcher - CNRS]
Membrane Proteins and Membrane Systems Laboratory [Leader]
01 69 08 98 91 Saclay - Bât 532

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