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

Le cellule si connettono con la MEC e altre cellule tramite diversi complessi di adesione, chiamati collettivamente giunzioni di ancoraggio.
Nelle cellule epiteliali, le aderenze focali e gli emidesmosomi collegano i filamenti di actina e i filamenti intermedi a una forma specializzata di ECM chiamata lamina basale.
Gli emidesmosomi contengono una placca densa sul lato citosolico della membrana plasmatica formata dalla proteina citolinker plectina.
I filamenti intermedi contenenti cheratina sono collegati a questa placca tramite integrine alfa sei, beta quattro e altre proteine come BP230 e BP180.
Sulla faccia della MEC, le integrine legano la laminina, una glicoproteina che è un componente importante della lamina basale.
Gli emidesmosomi risultanti possono trasmettere segnali ECM aiutando la cellula a rispondere alle forze meccaniche e a cambiare forma, polarità e direzione di migrazione.

<ol>
	<li>Wei, Qi e Hayden Huang. "Approfondimenti sul ruolo delle giunzioni cellula-cellula nella fisiologia e nella malattia". Revisione internazionale della biologia cellulare e molecolare 306 (2013): 187-221.</li>
	<li>Seetharaman, Shailaja e Sandrine Etienne-Manneville. "Crosstalk citoscheletrico nella migrazione cellulare". Trends in Cell Biology 30, n. 9 (2020): 720-735.</li>
	<li>https://www.mechanobio.info/what-is-mechanosignaling/what-are-cell-cell-adhesions/what-are-anchoring-junctions/</li>
</ol>

giunzioni di ancoraggio

Anchoring Junctions

Le giunzioni di ancoraggio sono complessi multiproteici che aiutano le cellule a connettersi ad altre cellule e alla matrice extracellulare. Le giunzioni di ancoraggio sono presenti sulle superfici laterali e basali delle cellule, fornendo connessioni forti e flessibili. Le adesioni focali si formano spesso a causa delle interazioni cellulari con i substrati dell'ECM, che avviano la trasduzione del segnale tramite cascate di chinasi e altri meccanismi. Insieme, forniscono stabilità e integrità dei tessuti. Esistono tre tipi di giunzioni di ancoraggio: desmosomi, emidesmosomi e aderenti.

I desmosomi appaiono come placche dense, simmetriche, a forma di disco sulla membrana cellulare. Le proteine di adesione chiamate caderine sono coinvolte nella formazione della placca. L’aspetto distintivo è dovuto alle proteine strutturali sulla superficie interna della membrana cellulare.

Gli emidesmosomi assomigliano a mezzo desmosoma e collegano le cellule alla lamina basale. Sebbene simili nell'aspetto ai desmosomi, includono proteine di adesione chiamate integrine anziché caderine. Queste connessioni sono essenziali per tenere insieme le cellule.

Le giunzioni aderenti utilizzano caderine o integrine a seconda che si colleghino ad altre cellule o alla matrice. Le giunzioni sono caratterizzate dalla presenza della proteina contrattile actina situata sulla superficie citoplasmatica della membrana cellulare. L'actina può collegare zone isolate o formare una struttura a cintura all'interno della cellula.

Le tre giunzioni di ancoraggio influenzano la forma e il ripiegamento del tessuto epiteliale.

Adapted from section 4.2 Epithelial tissue- Anatomy and Physiology 2 e, Openstax

Giunzioni di ancoraggio

Le giunzioni di ancoraggio sono complessi multiproteici che aiutano le cellule a connettersi ad altre cellule e alla matrice extracellulare. Le giunzioni di ancoraggio sono presenti ...

Education

Didattica

JoVE Core

Cell Biology

Biologia cellulare

Unit 1

Unità 1

Cell-Matrix Interactions

Interazioni cellula-matrice

KEY TERMS AND CONCEPTS

TERMINI E CONCETTI CHIAVE

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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