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

Os desmossomos são junções de ancoragem encontradas mais abundantemente em tecidos que sofrem estresse mecânico, como o músculo cardíaco e o epitélio intestinal.
A adesão celular nos desmossomos é facilitada por caderinas desmossomais, ou seja, desmocolina e desmogleína, que aderem por meio de interações heterofílicas de seus domínios extracelulares.
O domínio citoplasmático das caderinas liga-se a cateninas chamadas placoglobinas e placofilinas, que formam uma placa densa no lado citoplasmático.
As cateninas não podem se ligar diretamente aos filamentos intermediários e estão ligadas a eles pela desmoplaquina - uma proteína ligante do citoesqueleto pertencente à família plakin.
O domínio N-terminal da desmoplakin liga-se às cateninas e suas repetições de plakina C-terminal ligam-se aos filamentos intermediários.
Assim, o desmossomo ancora os filamentos intermediários das células adjacentes, formando uma rede transcelular do citoesqueleto através do tecido.

<ol>
	<li>Delva, Emmanuella, Dana K. Tucker e Andrew P. Kowalczyk. "O desmossomo." Perspectivas de Cold Spring Harbor em biologia 1.2 (2009): a002543.</li>
	<li>Garrod, David e Martyn Chidgey. "Estrutura, composição e função do desmossomo." Biochimica et Biophysica Acta (BBA)-Biomembranes 1778.3 (2008): 572-587.</li>
	<li>Nekrasova, Oxana e Kathleen J. Green. "Montagem e dinâmica do desmossomo." Tendências em biologia celular 23.11 (2013): 537-546.</li>
</ol>

desmossomos

Desmosomes

O termo desmossomo deriva das palavras gregas "desmo" e "soma", que significam "corpos de adesão". Esta estrutura foi observada pela primeira vez no final de 1800 e descrita como nódulos pequenos e densos na epiderme. Os desmossomos são estruturas semelhantes a botões que ajudam a formar uma rede interligada de filamentos intermediários através das células. Essas junções são essenciais para manter as células unidas sob estresse mecânico e para manter a integridade do tecido. Os desmossomos são complexos multiproteicos compreendendo caderinas desmossômicas que estão ligadas a filamentos intermediários por meio de várias proteínas adaptadoras. Caderinas Desmossômicas As caderinas formam a região central extracelular de um desmossomo e ligam-se às caderinas na célula adjacente. Existem dois tipos de caderinas nos desmossomos – desmogleínas e desmocolinas. Estas glicoproteínas transmembrana possuem uma grande porção extracelular, englobando quatro repetições de caderina e um domínio de âncora extracelular que ancora estas proteínas à membrana celular. Pares heterodiméricos de desmogleínas e desmocolinas formam agrupamentos por interações cis na mesma célula e interações trans entre células adjacentes. Seus domínios citoplasmáticos podem variar em comprimento entre as diferentes isoformas devido ao splicing alternativo – por exemplo, existem quatro isoformas de desmogleína e três isoformas de desmocolina encontradas em humanos. Proteínas adaptadoras em desmossomos Os domínios citoplasmáticos das caderinas desmossômicas ligam-se à família de proteínas tatu chamadas placoglobina e placofilina, que formam uma placa densa. Essas proteínas têm repetições de braço características que funcionam como um local de ancoragem para diferentes proteínas ligantes, como a desmoplacina. A desmoplaquina é a proteína mais abundante em um complexo desmossômico. Seu terminal carboxi contém as repetições de plaquinas, que se ligam ao filamento intermediário, formando assim uma ligação entre a placa desmossômica e o citoesqueleto. Doenças da disfunção do desmossomo A disfunção desmossômica geralmente se manifesta como distúrbios do coração e da pele – tecidos normalmente submetidos a altos níveis de tensão mecânica. Por exemplo, mutações nos genes da desmogleína podem causar espessamento epidérmico e cardiomiopatia arritmogênica do ventrículo direito (ARVC). Além disso, os autoanticorpos direcionados às caderinas desmossômicas causam a doença autoimune pênfigo vulgar, na qual os pacientes apresentam bolhas epidérmicas devido à fraca adesão célula-célula.

Desmossomos

O termo desmossomo deriva das palavras gregas "desmo" e "soma" que significam "corpos de adesão". Esta estrutura foi observada pela primeira vez ...

Education

JoVE Core

Cell Biology

Biologia Celular

Unit 1

Unidade 1

Cell-Cell Interactions

Interações Célula-Célula

KEY TERMS AND CONCEPTS

TERMOS-CHAVE E CONCEITOS

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

Cell adhesion molecules help cells stick together and work as part of a tissue. They give multicellular organisms physical strength and also help cells send signals across the plasma membrane. These proteins are important for coordinated activity in tissues and organ systems. CAMs are grouped into four main families: integrins, cadherins, selectins, and immunoglobulin-like CAMs, or IgCAMs. Each family supports cell interactions in a different way. Some CAMs help cells attach firmly, while...

structure of cadherins

Cadherins in Cell Junctions and Disease

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

Cadherins Guide Cell Sorting in Tissues

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 - Biologia Celular ilustra processos celulares complexos em vídeos de animação fáceis de entender e, ao mesmo tempo, abrangentes. Esta coleção foca nos componentes e funções essenciais das células, incluindo organelas e membranas, transporte celular e energia celular. É complementado por vídeos de Cientistas em ação que demonstram a aplicação da biologia celular em experimentos de pesquisa do mundo real.

Desmosomes and Cell Anchoring

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