Soichiro Yamada

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Spatial and functional organization of cells in tissues is determined by cell-cell adhesion, thought to be initiated through trans-interactions between extracellular domains of the cadherin family of adhesion proteins, and strengthened by linkage to the actin cytoskeleton. Prevailing dogma is that cadherins are linked to the actin cytoskeleton through(More)
Epithelial cell-cell junctions, organized by adhesion proteins and the underlying actin cytoskeleton, are considered to be stable structures maintaining the structural integrity of tissues. Contrary to the idea that alpha-catenin links the adhesion protein E-cadherin through beta-catenin to the actin cytoskeleton, in the accompanying paper we report that(More)
Spatiotemporal coordination of cell-cell adhesion involving lamellipodial interactions, cadherin engagement, and the lateral expansion of the contact is poorly understood. Using high-resolution live-cell imaging, biosensors, and small molecule inhibitors, we investigate how Rac1 and RhoA regulate actin dynamics during de novo contact formation between pairs(More)
Keratins 5 and 14 polymerize to form the intermediate filament network in the progenitor basal cells of many stratified epithelia including epidermis, where it provides crucial mechanical support. Inherited mutations in K5 or K14 result in epidermolysis bullosa simplex (EBS), a skin-fragility disorder. The impact that such mutations exert on the intrinsic(More)
A major function shared by several types of cytoplasmic intermediate filaments (IFs) is to stabilize cellular architecture against the mechanical forces it is subjected to. As for other fibrous cytoskeletal arrays, a crucial determinant of this function is the spatial organization of IFs in the cytoplasm. However, very few crossbridging proteins are(More)
To establish laser-tracking microrheology (LTM) as a new technique for quantifying cytoskeletal mechanics, we measure viscoelastic moduli with wide bandwidth (5 decades) within living cells. With the first subcellular measurements of viscoelastic phase angles, LTM provides estimates of solid versus liquid behavior at different frequencies. In LTM, the(More)
Most type I and II keratin genes are spatially and temporally regulated in a pairwise manner in epithelial tissues, where they represent the major structural proteins. Epithelia can be partitioned into simple (single-layered) and complex (multilayered) types. We compared the structural and mechanical properties of natural keratin polymers occurring in(More)
Cytoskeletal regulation of cell adhesion is vital to the organization of multicellular structures. The focal adhesion protein zyxin emerged as a key regulator of actin assembly because zyxin recruits Enabled/vasodilator-stimulated phospho-proteins (Ena/VASP) to promote actin assembly. Zyxin also localizes to the sites of cell-cell adhesion and is thought to(More)
Eukaryotic cells feature two ubiquitous fibrous cytoskeletal polymers in their cytoplasm: F-actin and microtubules. A third fibrous polymer, intermediate filaments (IFs), appeared more recently in evolution (Fuchs and Cleveland, 1998; Erber et al., 1998). Two common traits define members of the family of IF proteins. First, these proteins exhibit a(More)
Keratin filaments arise from the copolymerization of type I and II sequences, and form a pancytoplasmic network that provides vital mechanical support to epithelial cells. Keratins 5 and 14 are expressed as a pair in basal cells of stratified epithelia, where they occur as bundled arrays of filaments. In vitro, bundles of K5-K14 filaments can be induced in(More)