Recent advances in structural biology research by Scintillon researchers

Left: high-resolution density;  Top: atomic model of interface; Right: conserved footprint on actin; Center phylogenetic tree of myosin.

Rapid tool for cell nanoarchitecture integrity assessment

Detailed three-dimensional contextual information of molecular processes is often necessary to understand these processes well enough to develop efficient drug-targeting and disease intervention strategies in all medical fields. We developed a tool that significantly accelerates studies providing such information (Gaietta et al., 2021 Journal of Structural Biology).

Structural basis of aE-catenin–F-actin catch bond behavior

A better understanding of how cell-cell contacts are maintained or broken is essential for unraveling the detailed mechanism of cancer progression. For example, cells need to detach to become metastatic and need to maintain contacts within a tumor. Our study significantly deepened our understanding of how cell-cell contacts work and thus potentially opens new opportunities for medical intervention in cancer progression (Xu et al., 2020 eLife).

The actomyosin interface contains an evolutionary conserved core and an ancillary interface involved in specificity

The knowledge obtained in our study has direct impact on drug-targeting strategies for malaria by telling researchers which regions of the interface are promising targets for disrupting the function of the malaria proteins while, at the same time, minimizing the potential of disrupting human protein interaction, thus preventing potential side effects (Robert-Paganin et al., 2021 Nature Communications).


Rapid tool for cell nanoarchitecture integrity assessment

The manuscript “Rapid tool for Cell nanoarchitecture Integrity Assessment” authored by Guido Gaietta*, Mark Swift, Niels Volkmann and Dorit Hanein* (*: shared corresponding authorship) was just published in Journal of Structural Biology. The manuscript describes an accessible, inexpensive, and reliable screening assay to rapidly report on the intracellular high-resolution structural integrity of cell preparations. The Rapid Cell Integrity Assessment (RCIA) screening assay is conducted at room temperature and relies solely on light microscopy imaging. RCIA can be used to test the effects on structural integrity for any type of cell perturbations including drug treatments, virus inactivation, biophysical manipulations, etc. The information provided by RCIA is complementary to other cell screening assays such as traditional cell viability tests by directly reporting on the intracellular high-resolution structural integrity of individual cells. Thus, RCIA protocol will significantly accelerate research and benefit all studies where the validity of conclusions relies on retaining the three-dimensional integrity of the intracellular landscape. Examples include in-situ cellular electron cryo-tomography, cellular super-resolution light microscopy, water-window Xray microscopy, cellular thermal shift assays, or in-cell nuclear magnetic resonance spectroscopy. Here we employ immunostaining protocols, as well as fluorescence and ins situ cellular cryogenic tomography.

Gaietta G, Swift MF, Volkmann N and Hanein D. Rapid tool for cell nanoarchitecture integrity assessment. Journal of Structural Biology (2021).

Structural basis of aE-catenin–F-actin catch bond behavior

The manuscript “Structural basis of aE-catenin–F-actin catch bond behavior” authored by Xiao-Ping Xu, Sabine Pokutta, Megan Torres, Mark F. Swift, Dorit Hanein*, Niels Volkmann* and William I. Weis* (*: shared corresponding authorship) was recently published in Elife. The development and maintenance of multicellular organisms depends upon specific adhesion between cells. Tissue integrity depends upon response of these adhesive structures to external mechanical perturbation. Cell-cell junctions transmit mechanical forces between cells. In some of these junctions the extracellular domains of cadherins mediate cell-cell contacts, and their cytoplasmic domains are linked to the actin cyto-skeleton by catenin. Here we describe an atomic structure of the aE-catenin actin-binding domain bound to actin filaments derived by cryogenic electron microscopy and image processing a resolution of 3.6Å. Through comparison with the solution structure of aE-catenin, we discovered how aE-catenin acts as a catch bond during initiation and maintenance of cell-cell contacts, a process essential for the development and maintenance of multicellular organisms. Here we employ molecular biology, biophysical assays, cryogenic electron microscopy and three-dimensional image reconstructions.

Xu XP, Pokutta S, Torres M, Swift MF, Hanein D, Volkmann N and Weis WI. Structural basis of αE-catenin-F-actin catch bond behavior. Elife, 9, (2020)

The actomyosin interface contains an evolutionary conserved core and an ancillary interface involved in specificity

The manuscript “The actomyosin interface contains an evolutionary conserved core and an ancillary interface involved in specificity” authored by Julien Robert-Paganin, Xiao-Ping Xu, Mark F. Swift, Daniel Auguin, James P. Robblee, Hailong Lu, Patricia M. Fagnant, Elena B. Krementsova, Kathleen M. Trybus, Anne Houdusse*, Niels Volkmann* and Dorit Hanein (*: shared corresponding authorship) was recently published in Nature Communications. Malaria is responsible for nearly half a million deaths per year. Both the motility and the infectivity of parasites from the genus Plasmodium, the causative agents of malaria, rely on a divergent actomyosin system composed of Myosin A (PfMyoA) and short filaments of actin 1 (PfAct1). In this work, we present the cryo-EM structure of PfAct1 decorated with the motor domain of PfMyoA at a resolution of 3.8 Å. The structure presented in our manuscript allowed us to visualize and to study this divergent actomyosin interface in detail. Through comparison with all other known high-resolution structures of myosin motor domains bound to actin filaments along the eukaryotic phylogenetic tree, we identify a conserved interface between actin and myosin that is consistent between all myosins and an ancillary interface that is responsible for specific myosin function.

Robert-Paganin J, Xu XP, Swift MF, Auguin D, Robblee JP, Lu H, Fagnant PM, Krementsova EB, Trybus KM, Houdusse A, Volkmann N, and Hanein D. The Actomyosin interface contains an evolutionary conserved core and an ancillary interface involved in specificity. Nature Communications, (2021).


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  • The Scintillon Institute
    published this page in News 2022-01-19 07:26:13 -0800