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Every Wednesday morning the UMR168 organizes seminars at Amphitheater Curie (map), from 11h30 to 12h30.

 You will also find in this section the PhD's defense adverts.

July 2014

Wednesday 2
Mathias Rief, (TU Münschen), hosted by P. Martin

ABSTRACT: Proteins are amazing molecular machines that can fold into a complex three dimensional structure in a self-organization process called protein folding.Even though powerful structural methods have allowed us taking still photographs of protein structures in atomic detail, the knowledge about the folding pathways and dynamics as well as material properties of those structures is rather limited. Over the past 15 years, our group has developed single mechanical methods to study the dynamics and mechanics of protein structures. In my talk I will discuss how these methods can be used to investigate and control the conformational mechanics of individual proteins. Examples include protein folding as well as protein-protein interactions and enzyme mechanics.

Thursday 3
Virgile Viasnoff, Associate Prof MechanoBiology Institute at NUS Singapore, hosted by M. Dahan
14:30 – 15:30 at Amphi Curie

Actin dynamics modulate mechanosensitive immobilization of E-cadherin at adherens junctions.

Mechanical stress is increasingly being shown to be a potent modulator of cell–cell junctional morphologies in developmental and homeostatic processes. Intercellular force sensing is thus expected to be an important regulator of cell signalling and tissue integrity. In particular, the interplay between myosin contractility, actin dynamics and E-cadherin recruitment largely remains to be uncovered. We devised a suspended cell doublet assay to quantitatively assess the correlation between myosin II activity and local E-cadherin recruitment. The single junction of the doublet exhibited a stereotypical morphology, with E-cadherin accumulating into clusters of varied concentrations at the rim of the circular contact. This local recruitment into clusters derived from the sequestration of E-cadherin through a myosin-II-driven modulation of actin turnover. I will show how the regulation of actin dynamics provides a mechanism for the mechanosensitive response of cell contacts. I will then provide examples of how the microenvironment around single cells can be controlled to force the spatial organization of the junction.

Engl et al, Nat Cell Biol. 2014 Jun;16(6):587-94 (Wilfried Engl, Bakya Arasi, Lai Lai Yap Jean-Paul Thiery and Virgile Viasnoff) 

Friday 4 
Dimitrios Stamou, Department of Chemistry, and Nano-Science Center, University of Copenhagen, Denmark, hosted by P. Bassereau
11:00 – 12:00 at Amphi Lacassagne

The importance of being Single: examples of molecules and signalling clusters in biology.

The main research theme at the Bio-Nanotechnology Laboratory is the nanoscale spatio-temporal organization of biological systems and its impact on normal and aberrant biological functions.

 In that context we are using fluorescence microscopy to study the structure, function and dynamics of single molecules. I will discuss here some of our recent work with GPCRs, and the Ras/SOS signaling system. We are also studying at the single particle level native and artificial vesicles, as exemplary supramolecular signaling complexes whose individual nanoscale properties can lead to the emergence of unique phenotypes. Here I will discuss the consequence of seemingly random intra-vesicle variations in size and lipid composition for vesicle trafficking and neurotransmission.


PhD's defense : 

Friday July 4th 
Coline Prévost, P. Bassereau Group
"Bending membranes and sensing curvature by I-BAR domain proteins"
14:00 – 15:00 at Amphi Lacassagne