Adhésion des Membranes et des cellules

Responsable : K. Sengupta


Actin-membrane interaction : in-vitro reconstitution of focal-adhesions
Principal investigators: K. SENGUPTA & E. HELFER 
PhD Student: M. Souissi
Collaborations: C. Le Clainche (I2BC), G. Giannone & O. Rossier (IINS)

Cell biophysics and proteomics have revealed key links between force, integrin and the mechanical properties of the extra cellular matrix (ECM). However, in-cellulo, the existence of multiple isoforms of actin binding proteins, their embedding in a complex signaling network, and their associated with a complex membrane environment precludes extraction of even elementary molecular mechanisms. To reveal these force-dependent molecular mechanisms, we need to isolate actomyosin-integrin-ECM circuits. The global objective of our project is to decipher the molecular links between actomyosin force, integrin regulation and ECM properties through in vitro reconstitution of focal adhesions.


Cell membrane organization and remodeling by the actin cytoskeleton (E. Helfer)

Cellular membranes are involved in crucial processes : for example, intracellular endosomes (closed membranes of a few 100nm in diameter) are responsible for precisely delivering compounds to specific targets in the cell (e.g. cell nucleus, endoplasmic reticulum, cell envelope). Using our reconstitution approach, we intend to decipher how the role of actin cytoskeleton in intracellular traffic, more precisely how it acts in sorting the endosomal content, in partitioning the endosomal membrane, and in the fission process of tubular membranes from the endosomes.

As a side project we used the same protein machinery to investigate the role of multivalent interactions in protein clustering at membranes

Interrogating the immune synapse by nano-patterned substrates

Principal investigators: K. SENGUPTA

PhD Student: A. Nassereddine

Collaborations: L. Limozin (LAI)


We aim to design innovative substrates and suitable detection techniques to understand better the dynamics and spatial organization associated with inter-cellular adhesion in general and the immunological synapse in particular. We create APC-mimetic synthetic substrates to study the impact of ligand clustering on T cell activation and spreading. The substrates exhibit antibodies directed against the TCR-complex in the form of a patterned array of sub micrometric dots surrounded by a polymer cushion or a fluid supported lipid bilayer (SLB) which may itself be functionalized with another bio-molecule.

T cell mechanobiology

Principal investigators: K. SENGUPTA

PhD Student: F. Mustafa

Collaborations: P-H. Puech, L. Limozin (LAI)

Funding: Doc2amu (amidex)

The ability of a T cell to explore environmental mechanical cues, through bonds formed by its special receptors called T cell receptors (TCRs), is crucial for the first steps of immune recognition.

We here recently shown that the response of T cells, quantified in terms of their spreading behavior, is biphasic with substrate stiffness when mediated through TCRs. However, when the ligands of the T cell integrins are additionally involved, the cellular response becomes monotonic. Based on a mesoscale model, this ligand-specific response can be attributed to differences in force sensitivity and effective stiffness of the link formed between the ligand/receptor pairs and the actin cytoskeleton. This may provide a general mechanism for immune cells to discriminate mechanosensitive bonds.

We are now exploring further the link between molecular mechanical properties  and cellular response.



Mechanical adaptation of monocytes in model lung capillary networks

Jules Dupire, Pierre-Henri Puech, Emmanuèle Helfer, Annie Viallat

Proceedings of the National Academy of Sciences of the United States of America 117:14798 (2020)

Molecular and Mechanobiological Pathways Related to the Physiopathology of FPLD2

Alice-Anaïs Varlet, Emmanuèle Helfer, Catherine Badens

Cells 9:1947 (2020)10.3390/cells9091947


Self-organization of red blood cell suspensions under confined 2D flows

Cécile Iss, Dorian Midou, Alexis Moreau, Delphine Held, Anne Charrier, Simon Mendez, Annie Viallat, Emmanuèle Helfer

Soft Matter (2019)10.1039/C8SM02571A

Biphasic mechanosensitivity of T cell receptor-mediated spreading of lymphocytes

Astrid Wahl, Céline Dinet, Pierre Dillard, Aya Nassereddine, Pierre-Henri Puech, Laurent Limozin, Kheya Sengupta

Proceedings of the National Academy of Sciences of the United States of America 116:5908-5913 (2019)10.1073/pnas.1811516116


T Cells on Engineered Substrates: The Impact of TCR Clustering Is Enhanced by LFA-1 Engagement

Emmanuelle Benard, Jacques Nunès, Laurent Limozin, Kheya Sengupta

Frontiers in Immunology 9 (2018)10.3389/fimmu.2018.02085

Lamellipod Reconstruction by Three-Dimensional Reflection Interference Contrast Nanoscopy (3D-RICN)

Marie-Julie Dejardin, Arnaud Hemmerle, Anais Sadoun, Yannick Hamon, Puech Pierre-Henri, Kheya Sengupta, Laurent Limozin

Nano Letters 18:6544-6550 (2018)10.1021/acs.nanolett.8b03134

When giant vesicles mimic red blood cell's dynamics: swinging of two-phase vesicles in shear flow

Simon Tusch, Etienne Loiseau, Al-Hair Al-Halifa, Kamel Khelloufi, Emmanuèle Helfer, Annie Viallat

Physical Review Fluids 3 (2018)10.1103/PhysRevFluids.3.123605


Printing functional protein nano-dots on soft elastomers: from transfer mechanism to cell mechanosensing

Ranime Alameddine, Astrid Wahl, Fuwei Pi, Kaoutar Bouzalmate, Laurent Limozin, Anne Charrier, Kheya Sengupta

Nano Letters 17:4284-4290 (2017)10.1021/acs.nanolett.7b01254

Ligand Nano-cluster Arrays in a Supported Lipid Bilayer

Emmanuelle Benard, Fuwei Pi, Igor Ozerov, Anne Charrier, Kheya Sengupta

Journal of visualized experiments : JoVE 122:e55060 (2017)10.3791/55060

Membrane fluctuations mediate lateral interaction between cadherin bonds

Susanne Fenz, Timo Bihr, Daniel Schmidt, Rudolf Merkel, Udo Seifert, Kheya Sengupta, Ana-Sunčana Smith

Nature Physics 13:906-913 (2017)10.1038/NPHYS4138

High Aspect Ratio Sub-Micrometer Channels Using Wet Etching: Application to the Dynamics of Red Blood Cell Transiting through Biomimetic Splenic Slits

Priya Gambhire, Scott Atwell, Cécile Iss, Frédéric Bedu, Igor Ozerov, Catherine Badens, Emmanuèle Helfer, Annie Viallat, Anne Charrier

Small 13:1700967 (2017)10.1002/smll.201700967


Nano-clustering of ligands on surrogate antigen presenting cells modulates T cell membrane adhesion and organization

Pierre Dillard, Fuwei Pi, Annemarie Lellouch, Laurent Limozin, Kheya Sengupta

Integrative biology 8:287-301 (2016)10.1039/C5IB00293A

Membrane Mediated Cooperativity Facilitates Cadherin Clustering in Model Membranes

Susanne Fenz, Timo Bihr, Daniel Schmidt, Rudolf Merkel, Kheya Sengupta, Udo Seifert, Ana-Suncana Smith

Biophysical Journal 110:190A (2016)10.1016/j.bpj.2015.11.1058

Measuring shape fluctuations in biological membranes

C. Monzel, K. Sengupta

Journal of Physics D: Applied Physics 49:243002 (2016)10.1088/0022-3727/49/24/243002

Dynamic Optical Displacement Spectroscopy to Quantify Biomembrane Bending Fluctuations

Cornelia Monzel, Daniel Schmidt, Udo Seifert, Ana-Suncana Smith, Kheya Sengupta, Rudolf Merkel

Biophysical Journal 110:487A (2016)10.1016/j.bpj.2015.11.2603

Nanometric thermal fluctuations of weakly confined biomembranes measured with microsecond time-resolution

Cornelia Monzel, Daniel Schmidt, Udo Seifert, Ana-Suncana Smith, Rudolf Merkel, Kheya Sengupta

Soft Matter 12:4755-4768 (2016)10.1039/c6sm00412a