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

I desmosomi sono giunzioni di ancoraggio che si trovano più abbondantemente nei tessuti che subiscono stress meccanico, come il muscolo cardiaco e l'epitelio intestinale.
L'adesione cellulare ai desmosomi è facilitata dalle caderine desmosomiali, vale a dire desmocollina e desmogleina, che aderiscono attraverso interazioni eterofile dei loro domini extracellulari.
Il dominio citoplasmatico delle caderine lega le catenine chiamate placoglobine e placofiline, che formano una placca densa sul lato citoplasmatico.
Le catenine non possono legare direttamente i filamenti intermedi e sono legate ad essi dalla desmoplachina, una proteina linker del citoscheletro appartenente alla famiglia delle plachin.
Il dominio N-terminale di Desmopla lega le catenine e le loro ripetizioni di plakin C-terminali legano i filamenti intermedi.
Pertanto, il desmossoma ancora i filamenti intermedi delle cellule adiacenti, formando una rete citoscheletrica transcellulare attraverso il tessuto.

<ol>
	<li>Delva, Emmanuella, Dana K. Tucker e Andrew P. Kowalczyk. "Il desmosoma". Prospettive di Cold Spring Harbor in biologia 1.2 (2009): a002543.</li>
	<li>Garrod, David e Martyn Chidgey. "Struttura, composizione e funzione del desmosoma". Biochimica et Biophysica Acta (BBA)-Biomembranes 1778.3 (2008): 572-587.</li>
	<li>Nekrasova, Oxana e Kathleen J. Green. "Assemblaggio e dinamica del desmosoma". Tendenze nella biologia cellulare 23.11 (2013): 537-546.</li>
</ol>

desmosomi

Desmosomes

Il termine desmosoma deriva dalle parole greche “desmo” e “soma” che significano “corpi di adesione”. Questa struttura fu osservata per la prima volta alla fine del 1800 e descritta come piccoli e densi noduli nell'epidermide. I desmosomi sono strutture simili a bottoni che aiutano a formare una rete interconnessa di filamenti intermedi attraverso le cellule. Queste giunzioni sono essenziali per tenere insieme le cellule sotto stress meccanico e per mantenere l'integrità dei tessuti. I desmosomi sono complessi multiproteici comprendenti caderine desmosomiali collegate ai filamenti intermedi tramite varie proteine adattatrici.

Caderine desmosomiali

Le caderine formano la regione centrale extracellulare di un desmosoma e legano le caderine sulla cellula adiacente. Ci sono due tipi di caderine nei desmosomi: desmogleine e desmocolline. Queste glicoproteine ​​transmembrana possiedono un'ampia porzione extracellulare comprendente quattro ripetizioni di caderina e un dominio di ancoraggio extracellulare che ancora queste proteine alla membrana cellulare. Coppie eterodimeriche di desmogleine e desmocolline formano cluster mediante interazioni cis sulla stessa cellula e interazioni trans tra cellule adiacenti. I loro domini citoplasmatici possono variare in lunghezza tra le diverse isoforme a causa dello splicing alternativo: ad esempio, ci sono quattro isoforme di desmogleina e tre isoforme di desmocollina trovate negli esseri umani.

Proteine adattatrici nei desmosomi

I domini citoplasmatici delle caderine desmosomiali legano la famiglia di proteine degli armadilli chiamate placoglobina e placofilina, che formano una placca densa. Queste proteine hanno le caratteristiche ripetizioni del braccio che funzionano come sito di aggancio per diverse proteine di collegamento, come la desmoplachina. La desmoplachina è la proteina più abbondante in un complesso desmosomiale. La loro parte carbossi-terminale contiene le ripetizioni della plakin, che legano il filamento intermedio, formando così un collegamento tra la placca desmosomiale e il citoscheletro.

Malattie della disfunzione del desmosoma

La disfunzione desmosomica di solito si manifesta come disturbi del cuore e della pelle, tessuti tipicamente sottoposti a livelli elevati di sforzo meccanico. Ad esempio, le mutazioni nei geni della desmogleina possono causare ispessimento epidermico e cardiomiopatia aritmogena del ventricolo destro (ARVC). Inoltre, gli autoanticorpi diretti contro le caderine desmosomiali causano la malattia autoimmune pemfigo volgare, in cui i pazienti presentano vesciche epidermiche a causa della debole adesione cellula-cellula.

Desmosomi

Il termine desmosomia deriva dalle parole greche "desmo" e "soma" che significano "corpi di adesione". Questa struttura è stata osservata per la prima volta ...

Education

Didattica

JoVE Core

Cell Biology

Biologia cellulare

Unit 1

Unità 1

Cell-Cell Interactions

Interazioni cellula-cellula

KEY TERMS AND CONCEPTS

TERMINI E CONCETTI CHIAVE

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

cell adhesion molecules - types and functions

cell-adhesion-molecules-types-and-functions

Cell Adhesion Molecules in Tissues

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structure of cadherins

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Cadherins are cell adhesion proteins that help cells stick together and build tissues. Their name comes from their calcium-dependent binding. Early examples were named E-cadherin, P-cadherin, and N-cadherin after the epithelial, placental, and neuronal cells where they were first found. Classical cadherins share similar sequences and structures. Other cadherins, including those involved in cell signaling, are grouped as non-classical cadherins. This diversity comes from multiple cadherin genes...

cadherins in tissue organization

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Cadherins help cells sort into the right tissues during development. They are a large superfamily of cell adhesion molecules, with more than 180 variants. Different tissues express specific cadherin combinations, which helps cells recognize and stick to the right neighbors. Cadherins usually bind to the same or a closely related cadherin on another cell. This is called homophilic binding. Because of this matching behavior, cells of the same type tend to group together and form clusters that...

catenins

Catenins in Cell Junctions and Signaling

Catenins help cells stay connected and also support signaling inside the body. These proteins act as linker proteins in cell junction complexes because they have multiple binding domains and flexible structures. Most catenins contain a protein sequence called the armadillo repeat, so they are also known as armadillo proteins. Alpha-catenin is the main exception. Catenins bind to cell adhesion molecules such as cadherins. They then connect cadherins to cytoskeletal proteins, and the exact link...

selectins

Selectins in Immune Cell Capture

Selectins help cells make short, temporary contacts during immune responses. They are cell adhesion molecules that bind carbohydrate ligands on other cells. These rod-like proteins have a long outside region and end in a lectin domain, which binds carbohydrates only when calcium ions are present. Three main selectins are known: L-selectin, P-selectin, and E-selectin. Their names reflect where they are found and how long they are. This tissue specificity helps explain why selectins act in...

immunoglobulin-like cell adhesion molecules

immunoglobulin-like-cell-adhesion-molecules

Ig-CAMs in Neural Growth and Disease

Ig-CAMs, or immunoglobulin-like cell adhesion molecules, are cell surface glycoproteins in the immunoglobulin superfamily. They contain immunoglobulin domains, and some also have fibronectin type III domains. Their Ig domains can be glycosylated to different degrees. These molecules can bind to the same kind of Ig-CAM or to other ligands, such as integrins. Most Ig-CAMs help cells stick together only for a short time. The nectin class is different because it helps form stable junctions,...

overview of cell-cell junctions

Cell Junctions in Tissues

Cell junctions help hold tissues together and let neighboring cells communicate. In multicellular organisms, the three-dimensional shape of tissues depends on interactions between cells and the extracellular matrix. Cell-cell junctions are specialized structures made of multi-protein complexes on one cell that connect with similar complexes on another cell. These junctions are grouped into three main types based on function: occluding, anchoring, and gap junctions. Tight junctions, also called...

adherens junctions

Cell Adhesion in Tissues and Infection

Adherens junctions are strong cell-to-cell anchors that help tissues stay connected. These anchoring junctions work with desmosomes, another type of junction that holds adjacent cells together. In many epithelial and endothelial tissues, adherens junctions form a continuous adhesion belt. In heart muscle, they often appear as clusters that help cells work together for coordinated contraction. Adherens junctions are also dynamic, especially in the cells that line blood vessels. These...

tension response at adherens junctions

How Adherens Junctions Sense Force

Adherens junctions help cells stay attached while they respond to mechanical force. These multi-protein complexes can adapt to tensile force and shear stress. When the force changes, mechanosensory proteins in the junction can change shape. This process is called mechanotransduction. Alpha-catenin is one of the main force-sensing proteins in adherens junctions. It is an allosteric protein, which means its shape affects how it works. Alpha-catenin has three VH, or vinculin homology, domains...

desmosomes

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...

tight junctions

Tight Junction Proteins and Cell Barriers

Tight junction proteins form seals between neighboring cells. These molecular barriers help stop fluids, ions, and other small solutes from leaking across body cavities and tissue compartments in multicellular organisms. They are an important part of cell barriers in places where controlled movement matters. The main tight junction proteins are claudin and occludin. Other proteins include tricellulin and JAM, which stands for junctional adhesion molecule. Most of these proteins are 4-pass...

gap junctions

Cell Communication Through Gap Junctions

Gap junctions let adjacent animal cells share small molecules, ions, and secondary messengers. These communication channels connect the cytoplasm of neighboring cells. They are built from many molecular channels, often from a few hundred to thousands in one junction. Each channel is made of two halves called connexon hemichannels. A connexon is a hexamer, meaning it is formed by six transmembrane connexin proteins. The six proteins arrange in a ring and create a pore in the center. One...

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

cell biology

JoVE Core Cell Biology illustrates complex cellular processes in easy-to-understand yet comprehensive animated video lessons. This collection focuses on the essential components and functions of cells, including organelles and membranes, cellular transport, and cell energetics. It is complemented by scientist-in-action videos that demonstrate the application of cell biology in real-world research experiments.

Desmosomes and Cell Anchoring

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