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All cell membranes present an electric potential. This is called the Resting Membrane Potential (RMP) and is the trace of the difference of ionic charges between the extracellular and the intracellular spaces. This is very well known in the so-called excitable cells (e.g. neurons, muscles) which can change their electric potential thanks to ion channels […]
Cryo-electron microcopy is revolutionising our vision of proteins and the cell (Nobel Prize 2017). One approach, known as isolated particle analysis, makes it possible to build atomic models of purified and homogeneous. At the same time, cryo-tomography (cryo-ET) is being developed to obtain molecular models of more complex samples, in vitro reconstituted or within cells […]
The vascular system, a prominent example of an ordered system, is a dynamic network of vessels that are regularly generated via processes such as angiogenesis [1]. It is well-known that endothelial cell monolayers, which coat the inner surfaces of blood vessels, typically form ordered arrangements with mixed orientations. Misalignments in such endothelial cell monolayers, either […]
The cell cytoskeleton is made up of polar protein filaments that interact with each other via various proteins, either fixed or motile. The filamentous aspect of its structure gives it properties that resemble those of polymer solutions and liquid crystals. The cytoskeleton however is active: thanks to a direct energy consumption or its coupling to […]
Environmental factors such as endocrine disrupting chemicals (EDC) are suspected to explain the rapidly increasing number of cases of Multiple Sclerosis (MS), a disease related to the progressive disruption of the protective myelin sheath that covers nerve fibers (Fig. 1A, Top). Our collaborators Sylvie Remaud (neuroendocrinologist, Musée National d’Histoire Naturelle) and Bernard Zalc (Neuroscientist, Institut […]
Sounds are detected in the inner ear by mechano-sensory “hair cells”. Hearing starts with sound-evoked deflections of the hair bundle, a cohesive tuft of stereocilia that works as the hair cell’s mechanical antenna (Fig. 1). These movements modulate tension in the tip links (Fig 1, inset) that pull on mechanosensitive ion channels, resulting in an […]
We are interested in the way chromatin organizes inside the nucleus, and in particular the interaction that arises between different kinds of chromatin (euchromatin and heterochromatin) and the nuclear membrane along the different growth phases of budding yeast. In recent investigations, we uncovered that heterochromatin forms aggregates that depend on a molecular glue (Sir3, Ruault […]
In addition to generating forces and reacting to mechanical cues, tissues are capable of actively transporting fluids and of creating electric currents. Tissues hydraulic properties are crucial during morphogenesis: for instance, mammalian embryos self-organize around spherical fluid cavities (lumens). Similarly, bioelectric properties of nonexcitable cells are crucial during wound healing, and suspected to play a […]
Sounds are detected and amplified in the inner ear by active mechano-sensory hair cells (see Figure). Hearing starts with the deflection of the hair bundle, a cohesive tuft of cylindrical protrusions that works as the hair cell’s mechanical antenna. Hair-bundle vibrations produce an electrical signal that is then transmitted to the brain. Importantly, the hair […]
Animal cells continually reshape and reorganize their surfaces to facilitate growth and development. The cell surface is a thin (~ 10 nm), essentially two-dimensional complex fluid. Its basic structure is provided by a lipid membrane. Notably, this membrane can undergo phase transition, giving rise to nano-scaled lipid domains [1]. These lipid domains play a crucial […]
Spatiotemporal patterns of gene expression are fundamental to every developmental program. The resulting gene expression domains are traditionally characterized by their levels of gene products. However, in vivo transcriptional dynamics are known to be highly dynamic, often stochastically fluctuating between periods of quiescence and periods of pronounced transcriptionally activity. To fully understand how patterns of […]
The evolutionary emergence of the primitive gut in Metazoa is one of the decisive events that conditioned the major evolutionary transition having led to the origin of animal development. It is thought to have been induced by the specification of the endomesoderm into the multicellular tissue and its invagination (i.e. gastrulation). However, the biochemical signals […]
The culture and differentiation of different types of stem cells is developing at a rapid pace. The aim is to succeed and create organs in vitro (“organoids”). The goals are both fundamental and therapeutic. On the one hand, it is a new way (the only one for human) to precisely understand how cells differentiate and […]
Recent studies have shown that cells are able to sense small topographical features and to respond to them by locally assembling different types of actin-based structures (actin-patches, podosomes) on these textures. These structures influence the motility of the cells, adhering or not to the surface (Fig.1A, Left), and the localization of podosomes in macrophages. Cell […]
We are interested in the way chromatin organizes inside the nucleus, and in particular how cellular activities define chromatin conformation and how this can affect the transcriptional regulation. In this project the focus is loop extrusion, a process that has been proposed to control transcription, and consists in the activity of a molecular motor (cohesin) that […]
Genetic renal kidney diseases lead to the development of numerous cysts in the renal tubules, ultimately leading to kidney failure. Despite extensive work on the genetics and cell biology of these diseases, the precise mechanism of cyst formation, resulting from localized dilatation of the renal tubules, remains imperfectly understood. Renal tubules have an extremely controlled […]
The ability to control the wavefront at the output of an imaging system allows to correct the imaging system optical aberration but also to impose a controlled deformation to encode specific information in the recorded images. Diffractive optical elements (DOE) provide an efficient mean to manipulate light. When placed in the back focal plane of […]
Emerging collective behaviors observed in multicellular biological tissues are controlled by the activity of the cells that make them up and by their mutual interactions. Such collective phenotypes include collective cell migration or organized supracellular tissue architectures; and span 2D and 3D geometries. However, in vivo, cell populations also strongly interact with their microenvironment via […]
Single molecule localization microscopy (SMLM) can reveal the molecular dynamics and molecule arrangements inside the cell at the nanometer scale. SMLM relies on the localization of the center of individual single molecules with a precision well below the diffraction limit of an optical microscope. The localization process repeated on the different acquisition frames results in […]
We are looking for a motivated master’s student to join our studies on tissue patterning and shape emergence during embryonic axis development. We are interested in understanding how mechanical cues, and possible feedbacks between mechanics and biochemical pathways, shape specific structures during the development of the anterior-posterior axis in a vertebrate embryo. More specifically, our […]
Understanding the self-organization of living systems is one of the biggest conceptual challenges of the present century. A generic mechanism that drives such organization is interaction among the individual elements — which may represent cells, bacteria, or even enzymes — via chemical signals. The ability of an individual cell to follow a gradient of chemicals […]
Super-resolution (SR) microscopy have revolutionized our understanding of the biological processes at the molecular level. Imaging single molecules and localizing their center with high precision allows the reconstruction of pointillist image of the sample with a resolution beyond the diffraction limit [1,2,3]. In order to capture the 3D nanoscale morphology of the whole cell, multifocus […]
Conformational changes and diffusion dynamics of membrane proteins are key in regulating fundamental cell physiology. Membrane proteins are involved in the transport of ions, drugs or molecules across the lipid bilayer using different sources of energy – during which they undergo specific conformations & spatial re-arrangement in membranes. We are interested in deciphering nanoscale conformations […]
The internship is part of a larger project which concerns the definition of the 3D structure of proteins forming membrane contact sites, by Cryo Electron Microscopy (EM), in vitro. We are particularly interested in understanding the architecture of the complex formed by VAP-A and OSBP between the endoplasmic reticulum and the golgi, a key complex […]
The mechanical, geometrical and chemical properties of the 3D fibrous extracellular matrix play a key role in cancer initiation and progression, by controlling the movement and fate of tumor cells as well as surrounding fibroblasts, immune or endothelial cells. A strong emphasis has been put recently on the development of matrices with controllable fiber properties […]
Temperature impacts all biochemical reactions inside a cell. For developing multicellular organisms, temperature fluctuations pose challenges because morphogenetic events depend on both, spatially and temporally coordinated cellular decisions. Despite this, most multicellular systems show a surprising degree of robustness with respect to temperature changes within certain temperature limits. With climate change pushing organisms more and […]