The Desmosome

Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia 30322, USA.
Cold Spring Harbor perspectives in biology (Impact Factor: 8.68). 08/2009; 1(2):a002543. DOI: 10.1101/cshperspect.a002543
Source: PubMed


Desmosomes are intercellular junctions that tether intermediate filaments to the plasma membrane. Desmogleins and desmocollins, members of the cadherin superfamily, mediate adhesion at desmosomes. Cytoplasmic components of the desmosome associate with the desmosomal cadherin tails through a series of protein interactions, which serve to recruit intermediate filaments to sites of desmosome assembly. These desmosomal plaque components include plakoglobin and the plakophilins, members of the armadillo gene family. Linkage to the cytoskeleton is mediated by the intermediate filament binding protein, desmoplakin, which associates with both plakoglobin and plakophilins. Although desmosomes are critical for maintaining stable cell-cell adhesion, emerging evidence indicates that they are also dynamic structures that contribute to cellular processes beyond that of cell adhesion. This article outlines the structure and function of the major desmosomal proteins, and explores the contributions of this protein complex to tissue architecture and morphogenesis.

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    • "The desmosomal cadherins, desmoglein (Dsg) and desmocollin (Dsc), form the adhesive interface of the desmosome and their cytoplasmic tails bind to the armadillo proteins, plakoglobin (PG) and plakophilin (PKP), in the desmosomal plaque. The armadillo proteins in turn bind to desmoplakin (DP), which links the desmosome to the IFs [6]–[10]. "
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    ABSTRACT: Desmosomes are intercellular adhesive junctions of major importance for tissue integrity. To allow cell motility and migration they are down-regulated in epidermal wound healing. Electron microscopy indicates that whole desmosomes are internalised by cells in tissues, but the mechanism of down-regulation is unclear. In this paper we provide an overview of the internalisation of half-desmosomes by cultured cells induced by calcium chelation. Our results show that: (i) half desmosome internalisation is dependent on conventional PKC isoforms; (ii) microtubules transport internalised half desmosomes to the region of the centrosome by a kinesin-dependent mechanism; (iii) desmosomal proteins remain colocalised after internalisation and are not recycled to the cell surface; (iv) internalised desmosomes are degraded by the combined action of lysosomes and proteasomes. We also confirm that half desmosome internalisation is dependent upon the actin cytoskeleton. These results suggest that half desmosomes are not disassembled and recycled during or after internalisation but instead are transported to the centrosomal region where they are degraded. These findings may have significance for the down-regulation of desmosomes in wounds.
    PLoS ONE 10/2014; 9(10):e108570. DOI:10.1371/journal.pone.0108570 · 3.23 Impact Factor
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    • "Desmosomes link the intermediate fi laments of two neighboring myocytes through a complex of proteins that have both mechanical and signaling properties (Delva et al., 2009). Evidence for the presence of specifi c desmosomal structures in the CCS is clear, and has been obtained through: (i) electron microscopy of desmosomal structures found at the SAN (Shimada et al., 2004; Saffi tz et al., 1997) and AVN (Vassall-Adams, 1983; Shimada et al., 2004) and (ii) immunohistochemical evidence of specifi c desmosomal components, such as desmoplakin, a central component of the desmosome (Dobrzynski et al., 2000) as well as plakoglobin (Lim et al., 2008) in the SAN and AVN. "
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    ABSTRACT: Anchoring cell junctions are integral in maintaining electro-mechanical coupling of ventricular working cardiomyocytes; however, their role in cardiomyocytes of the cardiac conduction system (CCS) remains less clear. Recent studies in genetic mouse models and humans highlight the appearance of these cell junctions alongside gap junctions in the CCS and also show that defects in these structures and their components are associated with conduction impairments in the CCS. Here we outline current evidence supporting an integral relationship between anchoring and gap junctions in the CCS. Specifically we focus on (1) molecular and ultrastructural evidence for cell-cell junctions in specialized cardiomyocytes of the CCS, (2) genetic mouse models specifically targeting cell-cell junction components in the heart which exhibit CCS conduction defects and (3) human clinical studies from patients with cell-cell junction-based diseases that exhibit CCS electrophysiological defects.
    Cell Communication & Adhesion 04/2014; 21(3). DOI:10.3109/15419061.2014.905928 · 1.52 Impact Factor
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    • "Both plakoglobin (Pg) and desmoplakin (DP) are proteins of the desmosomal adhesive complex (Waschke, 2008; Delva et al., 2009; Brooke et al., 2012). Desmosomes are found in epithelial cells and in a variety of cells of non-epithelial origin. "
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    ABSTRACT: Plakoglobin (Pg) and desmoplakin (DP) are adapter proteins within the desmosome, providing a mechanical link between desmosomal cadherins as transmembrane adhesion molecules and the intermediate filament cytoskeleton. Because in the severe skin blistering disease pemphigus autoantibodies against desmosomal adhesion molecules induce loss of keratinocyte cohesion at least in part via p38MAPK activation and depletion of desmosomal components, we evaluated the roles of Pg and DP in p38MAPK-dependent loss of cell adhesion. Silencing of either Pg or DP reduced cohesion of cultured human keratinocytes in dissociation assays. However, Pg but not DP silencing caused activation of p38MAPK-dependent keratin filament collapse and cell dissociation. Interestingly, extranuclear but not nuclear Pg rescued loss of cell adhesion and keratin retraction. In line with this, Pg regulated the levels of the desmosomal adhesion molecule desmoglein 3 and tethered p38MAPK to desmosomal complexes. Our data demonstrate a role of extranuclear Pg in controlling cell adhesion via p38MAPK-dependent regulation of keratin filament organization.Journal of Investigative Dermatology accepted article preview online, 17 January 2014. doi:10.1038/jid.2014.21.
    Journal of Investigative Dermatology 01/2014; 134(6). DOI:10.1038/jid.2014.21 · 7.22 Impact Factor
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