title: Zipper-like series of desmosomes supported by subplasmalemmal actin belts in thymic epithelial reticular cells in the rat.
abstract: Remodeling of epithelial tissues requires coordinated cell migration. Most of the mechanisms regulating desmosome assembly and stability in migrating epithelial cells are still unknown. The actin cytoskeleton is a significant component of desmosome assembly and maturation. The association of the actin cytoskeleton with adherens junctions requires additional ultrastructural investigations. A transmission electron microscopic study was performed on five samples of rat thymus. Interepithelial series of desmosomes up to 6.5 μm length were found as were composite series of junctions (tight, adherens, and desmosomes). As a particular feature, subplasmalemmal belts of microfilaments, apparently of actin, ran adjacent to the inner dense plaques of desmosomes, passing beneath and at a distance to the tight junctions. They were not found beneath the adherens junctions. The series of desmosomes were termed zipper-like desmosomes (ZLDs), and were either complete, or imperfect. Terminal imperfect or incomplete desmosomes were found at the ends of the zipper-like series. Alpha-smooth muscle actin immune labeling on six other samples of rat thymus was strongly suggestive of the existence of subplasmalemmal actin belts in the epithelial reticular system. Further studies are needed to establish the exact role of the ZLDs during processes of epithelial remodeling.
authors.affiliation: MEDCENTER, Center of Excellence in Laboratory Medicine and Pathology, Bucharest, Romania. Electronic address: anatomon@gmail.com.
authors.forename: M C
authors.initials: MC
authors.lastname: Rusu
authors.affiliation: Discipline of Pathologic Anatomy, Faculty of Medicine, "Carol Davila" University of Medicine and Pharmacy, Bucharest, Romania.
authors.forename: F
authors.initials: F
authors.lastname: Pop
authors.affiliation: Faculty of Geography, University of Bucharest, Romania.
authors.forename: V M
authors.initials: VM
authors.lastname: Mănoiu
authors.affiliation: Discipline of Physiology (I), Faculty of Medicine, "Carol Davila" University of Medicine and Pharmacy, Bucharest, Romania.
authors.forename: M O
authors.initials: MO
authors.lastname: Lupuşoru
authors.affiliation: Discipline of Embriology, Faculty of Dental Medicine, "Carol Davila" University of Medicine and Pharmacy, Bucharest, Romania.
authors.forename: A C
authors.initials: AC
authors.lastname: Didilescu
mesh_terms: D000199:Actins / Q000502:physiology*; D022005:Adherens Junctions / Q000502:physiology / Q000648:ultrastructure; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D003896:Desmosomes / Q000502:physiology* / Q000648:ultrastructure; D004847:Epithelial Cells / Q000378:metabolism / Q000502:physiology*; D007365:Intercellular Junctions / Q000502:physiology* / Q000648:ultrastructure; D008840:Microfilament Proteins / Q000502:physiology / Q000648:ultrastructure; D046529:Microscopy, Electron, Transmission; D051381:Rats; D017208:Rats, Wistar; D013950:Thymus Gland / Q000033:anatomy & histology / Q000378:metabolism / Q000502:physiology*; D019108:Tight Junctions / Q000502:physiology / Q000648:ultrastructure
chemical_list: D000199:Actins; D008840:Microfilament Proteins