Desmosomes play a crucial role in maintaining tissue barrier integrity, particularly in mechanically stressed tissues. The assembly of desmosomes is regulated by the cytoskeleton and its regulators, and desmosomes also function as a central hub for regulating F-actin. However, the specific mechanisms underlying the crosstalk between desmosomes and F-actin remain unclear. Here, we identified that ARHGAP32, a Rho GTPase-activating protein, is located in desmosomes through its interaction with desmoplakin (DSP) via its GAB2-interacting domain (GAB2-ID). We confirmed that ARHGAP32 is required for desmosomal organization, maturation and length regulation. Notably, loss of ARHGAP32 increased formation of F-actin stress fibers and phosphorylation of the regulatory myosin light chain Myl9 at T18/S19. Inhibition of ROCK activity in ARHGAP32-knockout (KO) cells effectively restored desmosomal organization and the integrity of epithelial cell sheets. Moreover, loss of DSP impaired desmosomal ARHGAP32 location and led to decreased actomyosin contractility. ARHGAP32 with a deletion of the GAB2-ID domain showed enhanced association with RhoA in the cytosol and failed to rescue the desmosomal organization in ARHGAP32-KO cells. Collectively, our study unveils that ARHGAP32 associates with and regulates desmosomes by interacting with DSP. This interaction potentially facilitates the crosstalk between desmosomes and F-actin.
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http://dx.doi.org/10.1242/jcs.261901 | DOI Listing |
J Cell Sci
October 2024
Amsterdam UMC, University of Amsterdam, Department of Medical Biochemistry, Amsterdam Cardiovascular Sciences, 1105 AZ, Amsterdam, The Netherlands.
Studies utilizing electron microscopy and live fluorescence microscopy have significantly enhanced our understanding of the molecular mechanisms that regulate junctional dynamics during homeostasis, development and disease. To fully grasp the enormous complexity of cell-cell adhesions, it is crucial to study the nanoscale architectures of tight junctions, adherens junctions and desmosomes. It is important to integrate these junctional architectures with the membrane morphology and cellular topography in which the junctions are embedded.
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September 2024
Department of Oral Medicine and Radiology, Kalinga Institute of Dental Sciences, Bhubaneswar, IND.
Introduction Eosin stain is a commonly used histological dye that selectively binds to acidic structures in cells, imparting a color between pink and red. Eosin stain can be harmful due to its chemical composition. Inhaling eosin stain in powder form or as aerosolized droplets can cause irritation in the respiratory tract.
View Article and Find Full Text PDFCell Tissue Res
December 2024
Laboratory for Stem Cells and Reproductive Cell Biology, Department of Histology and Embryology, Ankara University School of Medicine, Sihhiye, 06410, Ankara, Turkey.
The umbilical cord epithelium (UCE) is the surface tissue that covers the umbilical cord (UC). It is widely considered a single-layered epithelium composed of squamous or cuboidal cells, which are in constant contact with amniotic fluid. The objective of this study was to elucidate the distinctive structural characteristics and abundance of specific proteins in this unique epithelium, many of which have not been previously demonstrated.
View Article and Find Full Text PDFAllergol Select
October 2024
Center for Child and Adolescent Health, Helios Hospital Krefeld, Academic Hospital of RWTH Aachen, Krefeld.
Mol Biol Cell
November 2024
Department of Medicine Renal-Electrolyte Division and George M. O'Brien Pittsburgh Center for Kidney Research, University of Pittsburgh School of Medicine, Pittsburgh, PA.
The keratin cytoskeleton and associated desmosomes contribute to the mechanical stability of epithelial tissues, but their organization in native bladder umbrella cells and their responses to bladder filling are poorly understood. Using whole rat bladders in conjunction with confocal microscopy, super-resolution image processing, three-dimensional image reconstruction, and platinum replica electron microscopy, we identified a cortical cytoskeleton network in umbrella cells that was organized as a dense tile-like mesh comprised of tesserae bordered by cortical actin filaments, filled with keratin filaments, and cross-linked by plectin. Below these tesserae, keratin formed a subapical meshwork and at the cell periphery a band of keratin was linked via plectin to the junction-associated actin ring.
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