Biophysical Society Thematic Meeting | Singapore

Mechanobiology of Disease

Poster Abstracts

5-POS Board 5 Nanoscale Architecture of Cadherin-Mediated Adhesion.

Cristina Bertocchi 1 , Yilin Wang 1 , Andrea Ravasio 1 , Yusuke Hara 1 , Yao Wu 1 , Michelle A. Baird 2,3 , Talgat Sailov 4 , Michael W. Davidson 2 , Ronen Zaidel-Bar 1,6 , Yusuke Toyama 1,6 , Benoit Ladoux 1,5 , Pakorn Kanchanawong 1,6 .Rene Marc Mege 5 . 1 Mechanobiology Institute, Singapore, Singapore, 2 National High Magnetic Field Laboratory, Tallahassee, FL, USA, 3 National Heart Lung and Blood Institute, Bethesda, MD, USA, 4 Nanyang Technological University, Singapore, Singapore, 5 Université Paris Diderot/CNRS, Paris, France, 6 Department of Biomedical Engineering, NUS, Singapore, Singapore. Cadherin-mediated adhesions are highly dynamic complexes formed at sites of cell-cell contacts, essential for tissue homeostasis and multicellularity. Perturbations in their expression or function result in loss of intercellular adhesion with possible cell transformation and tumor progression. Recently, progress has been made in understanding the interaction between different components of these complexes and how they are deregulated in cancer cells. However, despite the central importance of such supramolecular complexes, their molecular organization remains unknown. Deciphering the molecular-scale organization of cadherin-adhesion-complexes requires determination of 3D distribution of specific proteins with accuracy matching their nanometer- length scale. While superresolution microscopy offers a potential avenue for dissecting nanoscale organization within these complexes, the inherently 3D geometry of the native cell-cell contacts pose limitations to achieving sub-20 nm resolution required for inferring molecular orientation. To overcome this issue, we utilized a biomimetic cadherin-coated substrate with which cells form cadherin-mediated complexes that recapitulate key attributes of early cell-cell contacts and which are highly amenable to superresolution imaging. Here we mapped the nanoscale organization of cadherin and key proteins of the cadhesome network in cells cultured on such biomimetic surface, observing a well-organized molecular architecture stratified along the z axis. The cadherin-catenin and actin compartments are separated by ~30 nm, interposed by a vinculin- containing interface. Vinculin can undergo a conformational activation, spanning between the cadherin-catenin layer and the actin compartment. Nanoscale positioning of vinculin was determined by alpha-catenin, while vinculin conformational state is controlled by contractility and/or Abl kinase phosphorylation at Y822 and, in turn, modulates the positioning of zyxin and VASP. In conclusion, our measurements reveal a modular nanoscale architecture of cadherin- based adhesions, suggesting a control principle whereby vinculin is a mechanical clutch that integrates mechanical and biochemical signals to differentially engage the cadherin-catenin complexes to the actomyosin contraction machinery.

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