@article {2018|2087, title = {The major β-catenin/E-cadherin junctional binding site is a primary molecular mechano-transductor of differentiation .}, journal = {Elife}, volume = {7}, year = {2018}, month = {2018 07 19}, abstract = {

, the primary molecular mechanotransductive events mechanically initiating cell differentiation remain unknown. Here we find the molecular stretching of the highly conserved Y654-β-catenin-D665-E-cadherin binding site as mechanically induced by tissue strain. It triggers the increase of accessibility of the Y654 site, target of the Src42A kinase phosphorylation leading to irreversible unbinding. Molecular dynamics simulations of the β-catenin/E-cadherin complex under a force mimicking a 6 pN physiological mechanical strain predict a local 45\% stretching between the two α-helices linked by the site and a 15\% increase in accessibility of the phosphorylation site. Both are quantitatively observed using FRET lifetime imaging and non-phospho Y654 specific antibody labelling, in response to the mechanical strains developed by endogenous and magnetically mimicked early mesoderm invagination of gastrulating embryos. This is followed by the predicted release of 16\% of β-catenin from junctions, observed in FRAP, which initiates the mechanical activation of the β-catenin pathway process.

}, keywords = {Amino Acid Sequence, Animals, Armadillo Domain Proteins, Binding Sites, Cadherins, Cell Differentiation, Drosophila melanogaster, Drosophila Proteins, Fluorescence Resonance Energy Transfer, Mechanotransduction, Cellular, Molecular Dynamics Simulation, Phosphorylation, Protein Binding, Protein Conformation, Proto-Oncogene Proteins pp60(c-src), Sequence Homology, Transcription Factors}, issn = {2050-084X}, doi = {10.7554/eLife.33381}, author = {R{\"o}per, Jens-Christian and Mitrossilis, D{\'e}mosth{\`e}ne and Guillaume Stirnemann and Waharte, Fran{\c c}ois and Brito, Isabel and Fernandez-Sanchez, Maria-Elena and Marc Baaden and Salamero, Jean and Farge, Emmanuel} } @article {2014|1598, title = {A predicted binding site for cholesterol on the GABAA receptor.}, journal = {Biophys. J.}, volume = {106}, number = {9}, year = {2014}, month = {may}, pages = {1938{\textendash}1949}, publisher = {Department of Physics, Rutgers University-Camden, Camden, New Jersey; Center for Computational and Integrative Biology, Rutgers University-Camden, Camden, New Jersey. Electronic address: Grace.Brannigan@rutgers.edu.}, abstract = {Modulation of the GABA type A receptor (GABAAR) function by cholesterol and other steroids is documented at the functional level, yet its structural basis is largely unknown. Current data on structurally related modulators suggest that cholesterol binds to subunit interfaces between transmembrane domains of the GABAAR. We construct homology models of a human GABAAR based on the structure of the glutamate-gated chloride channel GluCl of Caenorhabditis elegans. The models show the possibility of previously unreported disulfide bridges linking the M1 and M3 transmembrane helices in the α and γ subunits. We discuss the biological relevance of such disulfide bridges. Using our models, we investigate cholesterol binding to intersubunit cavities of the GABAAR transmembrane domain. We find that very similar binding modes are predicted independently by three approaches: analogy with ivermectin in the GluCl crystal structure, automated docking by AutoDock, and spontaneous rebinding events in unbiased molecular dynamics simulations. Taken together, the models and atomistic simulations suggest a somewhat flexible binding mode, with several possible orientations. Finally, we explore the possibility that cholesterol promotes pore opening through a wedge mechanism.}, keywords = {Amino Acid, Binding Sites, Caenorhabditis elegans Proteins, chemistry, chemistry/metabolism, Chloride Channels, Cholesterol, GABA-A, Humans, Hydrogen Bonding, Ivermectin, metabolism, Molecular Docking Simulation, Molecular Dynamics Simulation, Porosity, Protein Binding, Protein Conformation, Receptors, Sequence Homology, Substrate Specificity}, doi = {10.1016/j.bpj.2014.03.024}, author = {J{\'e}r{\^o}me H{\'e}nin and Salari, Reza and Murlidaran, Sruthi and Grace Brannigan} }