Name: desmosomes and cell anchoring
Uploaded: 2025-05-22T09:05:46.000Z
Duration: 1 min 5 s
Channel: JoVE

Les desmosomes sont des jonctions d’ancrage que l’on trouve plus abondamment dans les tissus qui subissent un stress mécanique, tels que le muscle cardiaque et l’épithélium intestinal.
L’adhésion cellulaire au niveau des desmosomes est facilitée par les cadhérines desmosomales, à savoir la desmocoline et la desmogléine, qui adhèrent via des interactions hétérophiles de leurs domaines extracellulaires.
Le domaine cytoplasmique des cadhérines se lie aux caténines appelées plakoglobines et plakophilines, qui forment une plaque dense sur le côté cytoplasmique.
Les caténines ne peuvent pas se lier directement aux filaments intermédiaires et leur sont liées par la desmoplakine, une protéine de liaison cytosquelettique appartenant à la famille des plakines.
Le domaine N-terminal de Desmoplakin se lie aux caténines, et leurs répétitions plakiniennes C-terminales lient les filaments intermédiaires.
Ainsi, le desmosome ancre les filaments intermédiaires des cellules adjacentes, formant un réseau cytosquelettique transcellulaire à travers le tissu.

<ol>
	<li>Delva, Emmanuella, Dana K. Tucker et Andrew P. Kowalczyk. « Le desmosome. » Perspectives de Cold Spring Harbor en biologie 1.2 (2009) : a002543.</li>
	<li>Garrod, David et Martyn Chidgey. « Structure, composition et fonction des desmosomes. » Biochimica et Biophysica Acta (BBA)-Biomembranes 1778.3 (2008) : 572-587.</li>
	<li>Nekrasova, Oxana et Kathleen J. Green. « Assemblage et dynamique des desmosomes. » Tendances en biologie cellulaire 23.11 (2013) : 537-546.</li>
</ol>

desmosomes

Desmosomes

Le terme desmosome dérive des mots grecs  “desmo” et “soma” signifiant  “corps d'adhésion”. Cette structure a été observée pour la première fois à la fin des années 1800 et décrite comme de petits nodules denses dans l'épiderme. Les desmosomes sont des structures en forme de bouton qui aident à former un réseau interconnecté de filaments intermédiaires à travers les cellules. Ces jonctions sont essentielles pour maintenir les cellules ensemble sous contrainte mécanique et pour maintenir l’intégrité des tissus. Les desmosomes sont des complexes multiprotéiques comprenant des cadhérines desmosomales liées à des filaments intermédiaires via diverses protéines adaptatrices.

Cadhérines desmosomales

Les cadhérines forment la région centrale extracellulaire d'un desmosome et se lient aux cellules adjacentes. Il existe deux types de cadhérines dans les desmosomes : les desmogléines et les desmocollines. Ces glycoprotéines transmembranaires possèdent une grande partie extracellulaire comprenant quatre répétitions de cadhérine et un domaine d'ancrage extracellulaire qui ancre ces protéines à la membrane cellulaire. Les paires hétérodimères de desmogléines et desmocollines forment des clusters par interactions cis sur la même cellule et interactions trans entre cellules adjacentes. Leurs domaines cytoplasmiques peuvent varier en longueur entre les différentes isoformes en raison d'un épissage alternatif - par exemple, il existe quatre isoformes de desmogléine et trois isoformes de desmocolline trouvées chez l'homme.

Protéines Adaptatrices dans les Desmosomes

Les domaines cytoplasmiques des cadhérines desmosomales se lient à la famille des protéines du tatou appelées plakoglobine et plakophiline, qui forment une plaque dense. Ces protéines ont les répétitions de bras caractéristiques qui fonctionnent comme un site d'accueil pour différentes protéines de liaison, telles que la desmoplakine. La desmoplakine est la protéine la plus abondante dans un complexe desmosomal. Leur carboxy-terminal contient les répétitions de plakine, qui se lient au filament intermédiaire, formant ainsi un lien entre la plaque desmosomale et le cytosquelette.

Maladies liées au Dysfonctionnement des Desmosomes

Le dysfonctionnement desmosomal se manifeste généralement par des troubles du cœur et de la peau - des tissus soumis généralement à des niveaux élevés de contraintes mécaniques. Par exemple, des mutations dans les gènes de la desmogléine peuvent provoquer un épaississement épidermique et une cardiomyopathie ventriculaire droite arythmogène (ARVC). De plus, les auto anticorps ciblant les cadhérines desmosomales provoquent la maladie auto-immune pemphigus vulgaris, dans laquelle les patients présentent des cloques épidermiques dues à une faible adhésion cellule-cellule.

Le terme desmosome dérive des mots grecs « desmo » et « soma » signifiant « corps d’adhésion ». Cette structure a été observée pour la première fois ...

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desmosomes and cell anchoring

Desmosomes are cell junctions that anchor cells together. They are button-like structures that create an interlinked network of intermediate filaments across cells. This strong link helps tissues resist mechanical stress and maintain tissue integrity.

Desmosomes are built from multiple proteins. Their core includes desmosomal cadherins, which are adhesion proteins that bind to cadherins on neighboring cells. The two desmosomal cadherins are desmogleins and desmocollins. These transmembrane glycoproteins have a large extracellular region with four cadherin repeats and one anchor domain that holds them in the cell membrane.

Desmogleins and desmocollins can pair as heterodimers. They form clusters through cis-interactions on the same cell and trans-interactions between adjacent cells. In humans, there are four desmoglein isoforms and three desmocollin isoforms, and their cytoplasmic domains can differ in length because of alternative splicing.

Inside the cell, the cadherins bind armadillo family proteins called plakoglobin and plakophilin. These proteins form a dense plaque. The plaque then recruits desmoplakin, the most abundant protein in a desmosomal complex. Desmoplakin uses its carboxy-terminal plakin repeats to bind intermediate filaments, which connects the desmosome to the cytoskeleton.

Problems with desmosomes often show up in the heart and skin, where cells face high mechanical strain. Mutations in desmoglein genes can cause epidermal thickening and arrhythmogenic right ventricular cardiomyopathy, or ARVC. Autoantibodies against desmosomal cadherins can also cause pemphigus vulgaris, an autoimmune disease that leads to epidermal blisters because cell-cell adhesion becomes weak.

Desmosomes and Cell Anchoring

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Desmosomes are cell junctions that anchor cells together. They are button-like structures that create an interlinked network of intermediate filaments across cells. This strong link helps tissues resist mechanical stress and maintain tissue integrity. Desmosomes are built from multiple proteins. Their core includes desmosomal cadherins, which are adhesion proteins that bind to cadherins on neighboring cells. The two desmosomal cadherins are desmogleins and desmocollins. These transmembrane...

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key terms and concepts

Learn how desmosomes hold cells together, link to intermediate filaments, and why defects can affect skin and heart tissue in humans.

Desmosomes and Cell Anchoring | JoVE K12

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Desmosomes and Cell Anchoring

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