Name: cell adhesion molecules in tissues
Uploaded: 2023-04-30T11:55:46.000Z
Duration: 1 min 20 s
Channel: JoVE

Les interactions cellulaires sont des points de contact physiques entre des cellules adjacentes. Ils aident à maintenir les cellules ensemble et permettent la communication transmembranaire, essentielle au fonctionnement coordonné des tissus.
Des interactions cellulaires stables se trouvent dans les tissus, tels que l’endothélium, où elles soutiennent l’organisation des tissus. À l’inverse, des interactions transitoires plus faibles aident à recruter des cellules qui se déplacent librement, comme les cellules immunitaires.
Ces interactions cellulaires se matérialisent par le biais de protéines spéciales de surface cellulaire, collectivement appelées molécules d’adhésion cellulaire ou CAM.
Parmi les quatre grandes familles de CAM, la famille des intégrines est impliquée dans l’interaction d’une cellule avec la matrice extracellulaire, tandis que les trois autres familles sont impliquées dans les interactions cellule-cellule.
Tout d’abord, il y a les cadhérines, qui forment des interactions stables en liant les cadhérines exprimées sur d’autres cellules.
Deuxièmement, il y a les selectins. Ils lient des glucides spécifiques à la surface d’autres cellules et forment des interactions transitoires.
Et enfin, les protéines de type immunoglobuline appartenant à la superfamille des immunoglobulines forment également des interactions transitoires en liant d’autres protéines et intégrines similaires sur d’autres cellules.

<ol>
	<li>Harjunpää, Heidi, et al. « Molécules d’adhésion cellulaire et leurs rôles et régulation dans le microenvironnement immunitaire et tumoral. » Frontières en immunologie (2019) : 1078.</li>
</ol>

molécules d'adhésion cellulaire - types et fonctions

Cell Adhesion Molecules - Types and Functions

Les molécules d'adhésion cellulaire (CAM) jouent un rôle essentiel dans la multicellularité et le fonctionnement coordonné des tissus et des systèmes organiques. Ils permettent les interactions physiques entre les cellules et confèrent une résistance mécanique aux tissus. Ils fonctionnent également comme récepteurs pour la transmission du signal à travers la membrane plasmique. Les CAM sont largement classés en quatre familles : les intégrines, les cadhérines, les sélectines et les CAM de type immunoglobuline (IgCAMs).

Familles CAM

La famille de protéines Intégrines est principalement impliquée dans l’interaction d’une cellule avec sa matrice environnante. Cependant, certaines intégrines peuvent se lier aux CAM à la surface d’une autre cellule et participer à des interactions directes cellule-cellule. Par exemple, les intégrines des cellules immunitaires se lient aux IgCAMs exprimées sur l’endothélium vasculaire.

Les cadhérines sont une superfamille de glycoprotéines dépendantes du calcium, principalement impliquées dans l'établissement de fortes adhésions cellulaires. Ils composent les jonctions adhérentes et les desmosomes dans les tissus, comme l'épithélium.

Les sélectines et les IgCAMs sont impliquées dans les interactions cellulaires transitoires et participent à l'orientation des cellules vers des sites cibles. Par exemple, ils contribuent au recrutement sélectif des lymphocytes vers les organes lymphoïdes secondaires.

CAM et Multicellularité

Les CAM se trouvent dans pratiquement tous les organismes multicellulaires – des éponges et simples nématodes aux invertébrés et vertébrés complexes. La complexité des interactions cellulaires, et donc des CAM, augmente avec la complexité des organismes. Par exemple, alors que la mouche des fruits D.melanogaster possède environ 500 gènes impliqués dans l’adhésion cellulaire, les vertébrés complexes comme les mammifères possèdent plus d’un millier de gènes codant pour différents types de CAM.

Molécules d'Adhésion Cellulaire - Types et Fonctions

Les molécules d’adhésion cellulaire (CAM) sont essentielles à la multicellularité et au fonctionnement coordonné des tissus et des systèmes organiques. Ils permettent ...

cell-adhesion-molecules-types-and-functions

Education

Enseignement

JoVE Core

Cell Biology

Biologie cellulaire

Unit 1

Unité 1

Cell-Cell Interactions

Interactions cellule-cellule

KEY TERMS AND CONCEPTS

TERMES ET CONCEPTS CLÉS

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 others help cells make short-lived contacts and move to the right place.

Integrins mainly help a cell interact with the surrounding matrix, which is the material around cells. Some integrins can also bind CAMs on another cell and take part in direct cell-cell contact. For example, integrins on immune cells bind IgCAMs on the vascular endothelium, the inner lining of blood vessels.

Cadherins are calcium-dependent glycoproteins. They are known for strong cell adhesion and help form adherens junctions and desmosomes in tissues such as epithelium. Selectins and IgCAMs usually support transient cell interactions. They also help guide cells to target sites, such as the selective recruitment of lymphocytes to secondary lymphoid organs.

CAMs are found in nearly all multicellular organisms, from sponges and simple nematodes to complex invertebrates and vertebrates. As organisms become more complex, their cell interactions and CAM systems also become more complex. For example, D. melanogaster has about 500 genes involved in cell adhesion, while mammals have over a thousand genes that code for different CAMs.

Cell Adhesion Molecules in Tissues

cell adhesion molecules - types and functions

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 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...

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 cell adhesion molecules help tissues stay strong, guide immune cells, and support cell signaling through four major CAM families.

Cell Adhesion Molecules in Tissues | JoVE K12

cell biology

JoVE Core Biologie cellulaire illustre les processus cellulaires complexes dans des leçons vidéos complètes mais faciles à comprendre. Cette collection se concentre sur les composants et fonctions essentiels de la cellule ; cela inclut les organelles et les membranes ainsi que le transport et le métabolisme énergétique cellulaire. Elle est complétée par nos vidéos de scientifiques à l'action qui démontrent l'application de la biologie cellulaire dans des expériences concrètes.

Cell Adhesion Molecules in Tissues

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