Name: cell adhesion in anchoring junctions
Uploaded: 2023-04-30T11:54:35.000Z
Duration: 1 min 3 s
Channel: JoVE

Cells connect with the ECM and other cells via different adhesion complexes, collectively called anchoring junctions.
In epithelial cells, focal adhesions and hemidesmosomes connect actin filaments, and intermediate filaments to a specialized form of ECM called the basal lamina.
Hemidesmosomes contain a dense plaque on the cytosolic side of the plasma membrane formed by the cytolinker protein plectin.
Keratin-containing intermediate filaments are connected to this plaque via alpha six beta four integrins and other&#160;proteins such as BP230, and BP180.
On the ECM face, the integrins bind laminin, a glycoprotein that is a major component of the basal lamina.
The resulting hemidesmosomes can transmit ECM signals helping the cell respond to mechanical forces and change shape, polarity, and direction of migration.

verankerende kruispunten

Anchoring Junctions

Ankerverbindingen zijn multiproteïnecomplexen die cellen helpen verbinding te maken met andere cellen en de extracellulaire matrix. Verankeringsverbindingen zijn aanwezig op de laterale en basale oppervlakken van cellen en zorgen voor sterke en flexibele verbindingen. Focale verklevingen worden vaak gevormd als gevolg van celinteracties met de ECM-substraten, die signaaltransductie initiëren via kinasecascades en andere mechanismen. Samen zorgen ze voor stabiliteit en weefselintegriteit. Er zijn drie soorten verankeringsverbindingen: desmosomen, hemidesmosomen en aanhangers.

Desmosomen verschijnen als dichte, symmetrische, schijfvormige plaques op het celmembraan. Adhesie-eiwitten, cadherines genaamd, zijn betrokken bij de vorming van plaques. Het onderscheidende uiterlijk is te danken aan structurele eiwitten op het binnenoppervlak van het celmembraan.

Hemidesmosomen zien eruit als een half desmosoom en verbinden cellen met de basale lamina. Hoewel ze qua uiterlijk lijken op desmosomen, bevatten ze de adhesie-eiwitten die integrinen worden genoemd in plaats van cadherinen. Deze verbindingen zijn essentieel om cellen bij elkaar te houden.

Adherens-verbindingen gebruiken cadherines of integrines, afhankelijk van of ze aan andere cellen of aan de matrix zijn gekoppeld. De verbindingen worden gekenmerkt door de aanwezigheid van het contractiele eiwit actine dat zich op het cytoplasmatische oppervlak van het celmembraan bevindt. De actine kan geïsoleerde plekken met elkaar verbinden of een riemachtige structuur in de cel vormen.

De drie verankeringsverbindingen beïnvloeden de vorm en vouwing van het epitheelweefsel.

Verankerende kruispunten

Anchoring junctions are multiprotein complexes that help cells connect to other cells and the extracellular matrix. Anchoring junctions are present on the ...

Education

JoVE Core

Cell Biology

Celbiologie

Unit 1

Eenheid 1

Cell-Matrix Interactions

Cel-matrixinteracties

KEY TERMS AND CONCEPTS

BELANGRIJKE TERMEN EN CONCEPTEN

cell adhesion in anchoring junctions

Anchoring junctions are multiprotein complexes that help cells connect to other cells and to the extracellular matrix. They sit on the lateral and basal surfaces of cells. These junctions create strong, flexible links that help maintain tissue stability and integrity.

Focal adhesions often form when cells interact with the extracellular matrix, or ECM, substrata. These contacts can start signal transduction through kinase cascades and other pathways. Together, these junctions help cells stay attached and support the structure of tissues.

There are three main types of anchoring junctions: desmosomes, hemidesmosomes, and adherens junctions. Desmosomes appear as dense, symmetrical, disc-shaped plaques on the cell membrane. Adhesion proteins called cadherins help form these plaques, and structural proteins on the inner surface of the membrane give them their distinct look.

Hemidesmosomes look like half a desmosome. They link cells to the basal lamina. Unlike desmosomes, hemidesmosomes use integrins instead of cadherins.

Adherens junctions can use cadherins or integrins, depending on whether they connect cells to other cells or to the matrix. These junctions are marked by actin, a contractile protein on the cytoplasmic side of the cell membrane. Actin may form isolated patches or a belt-like structure inside the cell.

Together, these three anchoring junctions help shape epithelial tissue and influence how it folds. They are essential for holding cells together and preserving tissue form.

Cell Adhesion in Anchoring Junctions

overview of cell-matrix interactions

ECM Proteins and Cell Signaling

The extracellular matrix, or ECM, is the material that helps hold cells together in a tissue. It also lets cells in that tissue communicate with one another. The ECM contains proteins such as fibronectin, collagen, and laminin. Collagen is the most abundant protein in this space. Collagen fibers are woven together with proteoglycans, which are protein molecules with carbohydrates attached. This mix gives the ECM its structure. It also supports cell migration and provides a scaffold for cell...

integrins

Integrins in Cell Adhesion

Integrins help animal and protozoan cells attach to the extracellular matrix, or ECM. These cells do not have cell walls, so the ECM helps maintain shape and provide structural stability. The ECM is a sticky network of carbohydrates and proteins found between adjacent cells. Some ECM proteins form a basement membrane, and other ECM parts adhere to it. Proteoglycans make up much of the ECM, while fibrous proteins such as collagen give it strength. Fibronectin connects proteoglycans and collagen...

activation of integrins

How Integrins Link Cells to Their Environment

Integrins help cells connect with their environment and send signals across the cell membrane. They can carry information from outside the cell to the inside, or from inside the cell to the outside. These two paths are called outside-in signaling and inside-out signaling. In outside-in signaling, molecules in the extracellular space bind to exposed ligand-binding sites on integrins. A ligand is a molecule that binds to a protein. This binding makes the inactive integrin change shape and become...

intracellular signaling affects focal adhesions

intracellular-signaling-affects-focal-adhesions

Integrins Trigger Focal Adhesion Signaling

Integrins trigger focal adhesion signaling at the cell membrane. These membrane receptors sit in the phospholipid bilayer with hydrophobic regions that match the membrane interior. They provide attachment sites for outside signals such as hormones and growth factors. When these effectors bind and become active, integrins can start response pathways inside the cell. Some integrin-driven pathways support cell growth and help cells survive. The signal begins at the membrane, but G-proteins and...

anchoring junctions

Anchoring junctions are multiprotein complexes that help cells connect to other cells and to the extracellular matrix. They sit on the lateral and basal surfaces of cells. These junctions create strong, flexible links that help maintain tissue stability and integrity. Focal adhesions often form when cells interact with the extracellular matrix, or ECM, substrata. These contacts can start signal transduction through kinase cascades and other pathways. Together, these junctions help cells stay...

cell-matrix's response to mechanical forces

cell-matrix-s-response-to-mechanical-forces

Focal Adhesions and Cell Mechanics

Focal adhesions help animal cells connect to the extracellular matrix and sense mechanical forces. The extracellular matrix, or ECM, sits outside cells and helps tissues withstand stress. It also sends signals from outside the cell to the inside. The ECM is large and its makeup changes from one tissue to another. In loose connective tissue, reticular fibers and ground substance form the ECM. In bone tissue, collagen and bone minerals make up the ECM. Anchoring junctions hold a cell to the...

key terms and concepts

Explore how desmosomes, hemidesmosomes, and adherens junctions connect cells to each other and the ECM to support tissue strength and shape.

Cell Adhesion in Anchoring Junctions | 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.

Cell Adhesion in Anchoring Junctions

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