@article {2025|2170, title = {Across (Conformational) Space and (Relaxation) Time: Using Coarse-Grain Simulations to Probe the Intra- and Interdomain Dynamics of the Tau Protein.}, journal = {J Phys Chem B}, volume = {129}, year = {2025}, month = {2025 Nov 27}, pages = {12146-12158}, abstract = {

The biological importance of intrinsically disordered proteins (IDPs) has been established for over two decades, yet these systems remain difficult to characterize, as they are better described by conformational ensembles instead of a single reference structure for their folded counterparts. Tau is a prominent member of the IDP family, which sees its cellular function regulated by multiple phosphorylation sites and whose hyperphosphorylation is involved in neurodegenerative diseases such as Alzheimer\&$\#$39;s. We used coarse-grain MD simulations with the CALVADOS model to investigate the conformational landscape of tau without and with phosphorylations. Characterizing the local compactness of IDPs allows us to highlight how disorder comes in various flavors, as we can define different domains along the tau sequence. We define the IDP\&$\#$39;s Statistical Tertiary Organization (STO) as the average spatial arrangements of domains, which constitute an extension of the tertiary structure of folded proteins. We also use IDP-specific metrics to characterize the local curvature and flexibility of tau. Comparing the local flexibilities with T2 relaxation times from NMR experiments, we show how this metric is related to the protein dynamics. A curvature and flexibility pattern in the repeat domains can also be connected to tau binding properties, without having to explicitly model the protein\&$\#$39;s interaction partner. Finally, we rediscuss the original paperclip model that describes the spatial organization of tau and how phosphorylations impact it. The resulting changes in the protein intradomain and interdomain interaction pattern allow us to propose experimental setups to test our hypothesis.

}, keywords = {Humans, Intrinsically Disordered Proteins, Molecular Dynamics Simulation, Phosphorylation, Protein Conformation, Protein Domains, tau Proteins}, issn = {1520-5207}, doi = {10.1021/acs.jpcb.5c06282}, author = {Marien, Jules and Pr{\'e}vost, Chantal and S Sacquin-Mora} } @article {2025, title = {Impact of Multiple Phosphorylations on the Tau-R2/Tubulin Interface.}, journal = {Biochemistry}, volume = {64}, year = {2025}, month = {2025 Jul 01}, pages = {2916-2925}, abstract = {

The phosphorylation of the microtubule-associated tau protein plays a key role in the regulation of its physiological function. In particular, tau hyperphosphorylation affects its binding to the tubulin surface, destabilizing the tau-microtubule interface and leading to the accumulation of fibrillar aggregates in the brain. In this work, we performed classical molecular dynamics simulations for the tau-R2/tubulin assembly with various phosphorylation states of serines 285, 289, and 293. We analyze the resulting trajectories to obtain a detailed view of the protein interface in the complex and the impact of tau phosphorylations on the stability of this assembly and on the mobility of the tubulin disordered C-terminal tails (CTTs). We show how the tubulin CTTs help maintain the tau-R2 fragment on the tubulin surface despite the destabilizing effect induced by phosphorylations. Conversely, tau phosphorylation affects the CTTs\&$\#$39; flexibility and their potential activity as MAP-recruiting hooks. Furthermore, counterion-mediated bridges between the phosphate groups and tubulin glutamates also contribute to the binding of tau-R2 on the MT. Overall, the complex dynamics of this fuzzy phosphorylated assembly shed new light on the importance of the cytoplasmic environment in neurons in the context of Alzheimer\&$\#$39;s disease.

}, keywords = {Humans, Microtubules, Molecular Dynamics Simulation, Phosphorylation, Protein Binding, tau Proteins, Tubulin}, issn = {1520-4995}, doi = {10.1021/acs.biochem.5c00109}, author = {Marien, Jules and Pr{\'e}vost, Chantal and S Sacquin-Mora} } @article {2019|2081, title = {Visualizing Biological Membrane Organization and Dynamics.}, journal = {J Mol Biol}, volume = {431}, year = {2019}, month = {2019 05 03}, pages = {1889-1919}, abstract = {

Biological membranes are fascinating. Santiago Ram{\'o}n y Cajal, who received the Nobel prize in 1906 together with Camillo Golgi for their work on the nervous system, wrote \"[\…]in the study of this membrane[\…] I felt more profoundly than in any other subject of study the shuddering sensation of the unfathomable mystery of life\". The visualization and conceptualization of these biological objects have profoundly shaped many aspects of modern biology, drawing inspiration from experiments, computer simulations, and the imagination of scientists and artists. The aim of this review is to provide a fresh look on current ideas of biological membrane organization and dynamics by discussing selected examples across fields.

}, keywords = {Animals, Cell Membrane, Humans, Lipid Bilayers, Microscopy, Atomic Force, Microscopy, Electron, Transmission, Molecular Dynamics Simulation}, issn = {1089-8638}, doi = {10.1016/j.jmb.2019.02.018}, author = {Marc Baaden} } @article {2018|2093, title = {Dystrophin{\textquoteright}s central domain forms a complex filament that becomes disorganized by in-frame deletions.}, journal = {J Biol Chem}, volume = {293}, year = {2018}, month = {2018 05 04}, pages = {6637-6646}, abstract = {

Dystrophin, encoded by the gene, is critical for maintaining plasma membrane integrity during muscle contraction events. Mutations in the gene disrupting the reading frame prevent dystrophin production and result in severe Duchenne muscular dystrophy (DMD); in-frame internal deletions allow production of partly functional internally deleted dystrophin and result in less severe Becker muscular dystrophy (BMD). Many known BMD deletions occur in dystrophin\&$\#$39;s central domain, generally considered to be a monotonous rod-shaped domain based on the knowledge of spectrin family proteins. However, the effects caused by these deletions, ranging from asymptomatic to severe BMD, argue against the central domain serving only as a featureless scaffold. We undertook structural studies combining small-angle X-ray scattering and molecular modeling in an effort to uncover the structure of the central domain, as dystrophin has been refractory to characterization. We show that this domain appears to be a tortuous and complex filament that is profoundly disorganized by the most severe BMD deletion (loss of exons 45-47). Despite the preservation of large parts of the binding site for neuronal nitric oxide synthase (nNOS) in this deletion, computational approaches failed to recreate the association of dystrophin with nNOS. This observation is in agreement with a strong decrease of nNOS immunolocalization in muscle biopsies, a parameter related to the severity of BMD phenotypes. The structural description of the whole dystrophin central domain we present here is a first necessary step to improve the design of microdystrophin constructs toward the goal of a successful gene therapy for DMD.

}, keywords = {Binding Sites, Dystrophin, Exons, Gene Deletion, Humans, Molecular Docking Simulation, Muscular Dystrophy, Duchenne, Nitric Oxide Synthase Type I, Protein Domains, Reading Frames, Scattering, Small Angle, Solutions, X-Ray Diffraction}, issn = {1083-351X}, doi = {10.1074/jbc.M117.809798}, author = {Delalande, Olivier and Molza, Anne-Elisabeth and Dos Santos Morais, Raphael and Ch{\'e}ron, Ang{\'e}lique and Pollet, {\'E}meline and Raguenes-Nicol, C{\'e}line and Tascon, Christophe and Giudice, Emmanuel and Guilbaud, Marine and Nicolas, Aur{\'e}lie and Bondon, Arnaud and Leturcq, France and Nicolas F{\'e}rey and Marc Baaden and Perez, Javier and Roblin, Pierre and Pi{\'e}tri-Rouxel, France and Hubert, Jean-Fran{\c c}ois and Czjzek, Mirjam and Le Rumeur, Elisabeth} } @article {2018|2089, title = {Semantics for an Integrative and Immersive Pipeline Combining Visualization and Analysis of Molecular Data.}, journal = {J Integr Bioinform}, volume = {15}, year = {2018}, month = {2018 Jul 09}, abstract = {

The advances made in recent years in the field of structural biology significantly increased the throughput and complexity of data that scientists have to deal with. Combining and analyzing such heterogeneous amounts of data became a crucial time consumer in the daily tasks of scientists. However, only few efforts have been made to offer scientists an alternative to the standard compartmentalized tools they use to explore their data and that involve a regular back and forth between them. We propose here an integrated pipeline especially designed for immersive environments, promoting direct interactions on semantically linked 2D and 3D heterogeneous data, displayed in a common working space. The creation of a semantic definition describing the content and the context of a molecular scene leads to the creation of an intelligent system where data are (1) combined through pre-existing or inferred links present in our hierarchical definition of the concepts, (2) enriched with suitable and adaptive analyses proposed to the user with respect to the current task and (3) interactively presented in a unique working environment to be explored.

}, keywords = {Computer Graphics, Humans, Imaging, Three-Dimensional, Models, Structural, Semantics, Software, Statistics as Topic, User-Computer Interface}, issn = {1613-4516}, doi = {10.1515/jib-2018-0004}, author = {Trellet, Mikael and Nicolas F{\'e}rey and Floty{\'n}ski, Jakub and Marc Baaden and Bourdot, Patrick} } @article {2017|2036, title = {VLITL is a major cross-β-sheet signal for fibrinogen Aα-chain frameshift variants.}, journal = {Blood}, volume = {130}, year = {2017}, month = {2017 12 21}, pages = {2799-2807}, abstract = {

The first case of hereditary fibrinogen Aα-chain amyloidosis was recognized \>20 years ago, but disease mechanisms still remain unknown. Here we report detailed clinical and proteomics studies of a French kindred with a novel amyloidogenic fibrinogen Aα-chain frameshift variant, Phe521Leufs, causing a severe familial form of renal amyloidosis. Next, we focused our investigations to elucidate the molecular basis that render this Aα-chain variant amyloidogenic. We show that a 49-mer peptide derived from the C-terminal part of the Phe521Leufs chain is deposited as fibrils in the patient\&$\#$39;s kidneys, establishing that only a small portion of Phe521Leufs directly contributes to amyloid formation in vivo. In silico analysis indicated that this 49-mer Aα-chain peptide contained a motif (VLITL), with a high intrinsic propensity for β-aggregation at residues 44 to 48 of human renal fibrils. To experimentally verify the amyloid propensity of VLITL, we generated synthetic Phe521Leufs-derived peptides and compared their capacity for fibril formation in vitro with that of their VLITL-deleted counterparts. We show that VLITL forms typical amyloid fibrils in vitro and is a major signal for cross-β-sheet self-association of the 49-mer Phe521Leufs peptide identified in vivo, whereas its absence abrogates fibril formation. This study provides compelling evidence that VLITL confers amyloidogenic properties to Aα-chain frameshift variants, yielding a previously unknown molecular basis for the pathogenesis of Aα-chain amyloidosis.

}, keywords = {Amino Acid Motifs, Amino Acid Sequence, Amyloid, Amyloidosis, Familial, Fibrinogen, Frameshift Mutation, Humans, Kidney, Protein Conformation, beta-Strand}, issn = {1528-0020}, doi = {10.1182/blood-2017-07-796185}, author = {Garnier, Cyrille and Briki, Fatma and Nedelec, Brigitte and Le Pogamp, Patrick and Dogan, Ahmet and Rioux-Leclercq, Nathalie and Goude, Renan and Beugnet, Caroline and Martin, Laurent and Delpech, Marc and Bridoux, Frank and Grateau, Gilles and Doucet, Jean and Philippe Derreumaux and Valleix, Sophie} } @article {2017|2042, title = {What Can Human-Guided Simulations Bring to RNA Folding?}, journal = {Biophys J}, volume = {113}, year = {2017}, month = {2017 Jul 25}, pages = {302-312}, abstract = {

Inspired by the recent success of scientific-discovery games for predicting protein tertiary and RNA secondary structures, we have developed an open software for coarse-grained RNA folding simulations, guided by human intuition. To determine the extent to which interactive simulations can accurately predict 3D RNA structures of increasing complexity and lengths (four RNAs with 22-47 nucleotides), an interactive experiment was conducted with 141 participants who had very little knowledge of nucleic acids systems and computer simulations, and had received only a brief description of the important forces stabilizing RNA structures. Their structures and full trajectories have been analyzed statistically and compared to standard replica exchange molecular dynamics simulations. Our analyses show that participants gain easily chemical intelligence to fold simple and nontrivial topologies, with little computer time, and this result opens the door for the use of human-guided simulations to RNA folding. Our experiment shows that interactive simulations have better chances of success when the user widely explores the conformational space. Interestingly, providing on-the-fly feedback of the root mean square deviation with respect to the experimental structure did not improve the quality of the proposed models.

}, keywords = {Access to Information, Computer Simulation, Feedback, Psychological, Humans, Internet, Models, Genetic, Models, Molecular, RNA, RNA Folding, Software, Solvents}, issn = {1542-0086}, doi = {10.1016/j.bpj.2017.05.047}, author = {Mazzanti, Liuba and Doutreligne, S{\'e}bastien and Gageat, Cedric and Philippe Derreumaux and Antoine Taly and Marc Baaden and Pasquali, Samuela} } @article {2017|2030, title = {Why Is Research on Amyloid-β Failing to Give New Drugs for Alzheimer{\textquoteright}s Disease?}, journal = {ACS Chem Neurosci}, volume = {8}, year = {2017}, month = {2017 Jul 19}, pages = {1435-1437}, abstract = {

The two hallmarks of Alzheimer\&$\#$39;s disease (AD) are the presence of neurofibrillary tangles (NFT) made of aggregates of the hyperphosphorylated tau protein and of amyloid plaques composed of amyloid-β (Aβ) peptides, primarily Aβ1-40 and Aβ1-42. Targeting the production, aggregation, and toxicity of Aβ with small molecule drugs or antibodies is an active area of AD research due to the general acceptance of the amyloid cascade hypothesis, but thus far all drugs targeting Aβ have failed. From a review of the recent literature and our own experience based on in vitro, in silico, and in vivo studies, we present some reasons to explain this repetitive failure.

}, keywords = {Alzheimer Disease, Amyloid beta-Peptides, Animals, Drug Discovery, Humans, Neuroprotective Agents}, issn = {1948-7193}, doi = {10.1021/acschemneuro.7b00188}, author = {Doig, Andrew J and Del Castillo-Frias, Maria P and Berthoumieu, Olivia and Tarus, Bogdan and Nasica-Labouze, Jessica and Sterpone, Fabio and Phuong Hoang Nguyen and Hooper, Nigel M and Faller, Peter and Philippe Derreumaux} } @article {2014|1792, title = {Allosteric regulation of pentameric ligand-gated ion channels: An emerging mechanistic perspective}, journal = {Channels}, volume = {8}, number = {4}, year = {2014}, pages = {350{\textendash}360}, keywords = {Allosteric Regulation, Animals, chemistry/metabolism, Humans, Ion Channel Gating, Ligand-Gated Ion Channels, metabolism, Models, Molecular, Protein Multimerization, Small Molecule Libraries}, author = {Antoine Taly and J{\'e}r{\^o}me H{\'e}nin and Changeux, Jean-Pierre and Cecchini, Marco} } @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} } @article {2010|1789, title = {Single-spanning transmembrane domains in cell growth and cell-cell interactions: More than meets the eye?}, journal = {Cell Adh. Migr.}, volume = {4}, number = {2}, year = {2010}, month = {apr}, pages = {313{\textendash}324}, abstract = {

As a whole, integral membrane proteins represent about one third of sequenced genomes, and more than 50\% of currently available drugs target membrane proteins, often cell surface receptors. Some membrane protein classes, with a defined number of transmembrane (TM) helices, are receiving much attention because of their great functional and pharmacological importance, such as G protein-coupled receptors possessing 7 TM segments. Although they represent roughly half of all membrane proteins, bitopic proteins (with only 1 TM helix) have so far been less well characterized. Though they include many essential families of receptors, such as adhesion molecules and receptor tyrosine kinases, many of which are excellent targets for biopharmaceuticals (peptides, antibodies, et al.). A growing body of evidence suggests a major role for interactions between TM domains of these receptors in signaling, through homo and heteromeric associations, conformational changes, assembly of signaling platforms, etc. Significantly, mutations within single domains are frequent in human disease, such as cancer or developmental disorders. This review attempts to give an overview of current knowledge about these interactions, from structural data to therapeutic perspectives, focusing on bitopic proteins involved in cell signaling.

}, keywords = {Animals, Biological, Humans, Membrane Proteins, Models, Protein Structure, Secondary, Signal Transduction, Tertiary}, issn = {1933-6926}, doi = {10.4161/cam.4.2.12430}, author = {Pierre Hubert and Paul Sawma and Jean-Pierre Duneau and Jonathan Khao and J{\'e}r{\^o}me H{\'e}nin and Dominique Bagnard and James Sturgis} } @article {2009|2009, title = {Structural diversity of the soluble trimers of the human amylin(20-29) peptide revealed by molecular dynamics simulations}, journal = {J. Chem. Phys.}, volume = {130}, number = {12}, year = {2009}, month = {mar}, pages = {125101}, keywords = {Amino Acid Sequence, Amyloid, Humans, Models, Molecular, Molecular Sequence Data, Peptide Fragments, Protein Multimerization, Protein Structure, Quaternary, Solubility, Solvents}, doi = {10.1063/1.3097982}, author = {Mo, Yuxiang and Lu, Yan and Wei, Guanghong and Philippe Derreumaux} } @article {2006|1935, title = {HDAC1 acetylation is linked to progressive modulation of steroid receptor-induced gene transcription.}, journal = {Mol. Cell}, volume = {22}, number = {5}, year = {2006}, month = {jun}, pages = {669{\textendash}679}, publisher = {Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Building 41, B602, Bethesda, Maryland 20892, USA.}, abstract = {Although histone deacetylases (HDACs) are generally viewed as corepressors, we show that HDAC1 serves as a coactivator for the glucocorticoid receptor (GR). Furthermore, a subfraction of cellular HDAC1 is acetylated after association with the GR, and this acetylation event correlates with a decrease in promoter activity. HDAC1 in repressed chromatin is highly acetylated, while the deacetylase found on transcriptionally active chromatin manifests a low level of acetylation. Acetylation of purified HDAC1 inactivates its deacetylase activity, and mutation of the critical acetylation sites abrogates HDAC1 function in vivo. We propose that hormone activation of the receptor leads to progressive acetylation of HDAC1 in vivo, which in turn inhibits the deacetylase activity of the enzyme and prevents a deacetylation event that is required for promoter activation. These findings indicate that HDAC1 is required for the induction of some genes by the GR, and this activator function is dynamically modulated by acetylation.}, keywords = {Acetylation, Amino Acid Sequence, Animals, Binding Sites, Cell Cycle Proteins, Chromatin, Down-Regulation, genetics/metabolism, Hela Cells, Histone Acetyltransferases, Histone Deacetylases, Humans, immunology/metabolism, metabolism}, doi = {10.1016/j.molcel.2006.04.019}, author = {Yi Qiu and Yingming Zhao and Matthias Becker and Sam John and Bhavin S Parekh and Suming Huang and Anindya Hendarwanto and Elisabeth D Martinez and Yue Chen and Hanxin Lu and Nicholas L Adkins and Diana A Stavreva and Malgorzata Wiench and Philippe T Geor} } @article {2005|1775, title = {Chromatin remodeling complexes: ATP-dependent machines in action.}, journal = {Biochem. Cell Biol.}, volume = {83}, number = {4}, year = {2005}, month = {aug}, pages = {405{\textendash}417}, publisher = {Division of Biological Sciences, Marshall University, Huntington, WV 25755, USA.}, abstract = {Since the initial characterization of chromatin remodeling as an ATP-dependent process, many studies have given us insight into how nucleosome-remodeling complexes can affect various nuclear functions. However, the multistep DNA-histone remodeling process has not been completely elucidated. Although new studies are published on a nearly weekly basis, the nature and roles of interactions of the individual SWI/SNF- and ISWI-based remodeling complexes and DNA, core histones, and other chromatin-associated proteins are not fully understood. In addition, the potential changes associated with ATP recruitment and its subsequent hydrolysis have not been fully characterized. This review explores possible mechanisms by which chromatin-remodeling complexes are recruited to specific loci, use ATP hydrolysis to achieve actual remodeling through disruption of DNA-histone interactions, and are released from their chromatin template. We propose possible roles for ATP hydrolysis in a chromatin-release/target-scanning process that offer an alternative to or complement the often overlooked function of delivering the energy required for sliding or dislodging specific subsets of core histones.}, keywords = {Adenosine Triphosphatases, Adenosine Triphosphate, Animals, Chromatin, Gene Expression Regulation, genetics/metabolism, Humans, metabolism, Nucleosomes, Transcription Factors}, doi = {10.1139/o05-115}, author = {Cotteka N Johnson and Nicholas L Adkins and Philippe Georgel} }