Membranes and cellular functions

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Keywords : Intracellular transport, Membrane nanotubes, membrane mechanics, protein diffusion, Biomimetic membranes, myosins, synthetic biology



Lipid membranes exhibit non-trivial properties especially at length scales much larger than molecular sizes. Purely molecular description of membranes is not sufficient to achieve a quantitative understanding of their function, and meso-scale concepts coming from soft matter and statistical physics are necessary. In addition, cell membranes involve a large number of proteins that may have some activity and are inserted or interact with membranes, which completely changes the physical description. Our general goal is to contribute to a more comprehensive understanding of biological membranes and of their role in cells.

Model bio-membranes and cell membranes

Our group develops a multidisciplinary approach, largely based on synthetic biology, biomimetic systems and quantitative physics measurements, to understand the role of lipid membranes and associated proteins in essential cellular functions, such as:

  • intracellular trafficking, endo/exocytosis, cell infection, transmembrane transport of ions ("active membranes") and protein diffusion.

We also investigate both on live cells and on in vitro systems the mechanisms leading to filopodia formation and force generation by these cell structures.

We develop different model membrane systems, in particularly based on Giant Unilamellar Vesicles (GUV) and purified proteins (cytosolic or transmembrane). Our experiments generally combine quantitative confocal microscopy, optical tweezers, micromanipulation, micropipette aspiration, as well as single particle tracking for diffusion measurements. Since many projects address issues related to membrane deformation (curvature) and membrane mechanics, the group has developed assays with membrane nanotubes pulled from GUVs or from cells.

Our approaches and questions are motivated by our close collaborations with cell biologists at the Institut Curie and outside, with microbiologists and with theoreticians.

Key publications

Year of publication : 2015

Year of publication : 2014

Year of publication : 2013

Year of publication : 2012

Year of publication : 2011

  • Lipid and protein lateral mobility is essential for biological function. Our theoretical understanding of this mobility can be traced to the seminal work of Saffman and Delbrück, who predicted a logarithmic dependence of the protein diffusion coefficient (i) on the inverse of the size of the protein and (ii) on the “membrane size” for membranes of finite size [Saffman P, Delbrück M (1975) Proc Natl Acad Sci USA 72:3111—3113]. Although the experimental proof of the first prediction is a matter of debate, the second has not previously been thought to be experimentally accessible.

Year of publication : 2010

Year of publication : 2009