Name: integrins in cell adhesion
Uploaded: 2023-04-30T11:54:12.000Z
Duration: 1 min 10 s
Channel: JoVE

Le integrine sono una famiglia di recettori di adesione cellulare che legano i ligandi nella matrice extracellulare o ECM per mediare le aderenze cellula-matrice.
Passano da uno stato attivo a uno inattivo. Nella forma attiva, fungono da linker meccanici che collegano il citoscheletro alla matrice extracellulare.
L'integrina comprende subunità glicoproteiche alfa e beta associate in modo non covalente, formando un eterodimero transmembrana.
La coda C-terminale intracellulare della subunità beta interagisce con i filamenti di actina nel citosol attraverso proteine adattatrici come la talina e la paxillina. I grandi domini extracellulari N-terminali dell'integrina si legano a specifici motivi di sequenza di aminoacidi nelle proteine della MEC, come la sequenza RGD nella fibronectina.
Il complesso di adesione formato trasmette segnali in modo bidirezionale attraverso la membrana plasmatica con l'aiuto di proteine effettrici, facilitando così la motilità, la crescita e la sopravvivenza cellulare.

<ol>
	<li>David G. Menter, Raymond N. DuBois, "Prostaglandine nell'adesione, migrazione e invasione delle cellule tumorali", International Journal of Cell Biology, vol. 2012, ID articolo 723419, 21 pagine, 2012. https://doi.org/10.1155/2012/723419</li>
	<li>Humphries, J. D., Byron, A., & Humphries, M. J. (2006). I ligandi delle integrine in sintesi. Giornale di scienza cellulare, 119(19), 3901-3903.</li>
	<li>Humphries, MJ (2000). Struttura delle integrine. Transazioni della società biochimica, 28(4), 311-340.</li>
</ol>

integrine

Integrins

Le cellule animali e protozoiche non hanno pareti cellulari per aiutare a mantenere la forma e fornire stabilità strutturale. Invece, queste cellule eucariotiche secernono una massa appiccicosa di carboidrati e proteine negli spazi tra le cellule adiacenti. Questa rete di proteine e molecole è chiamata matrice extracellulare o ECM.

Alcune proteine della matrice extracellulare si assemblano in una membrana basale alla quale aderiscono i restanti componenti. I proteoglicani costituiscono tipicamente la maggior parte dell’ECM mentre le proteine fibrose, come il collagene, forniscono forza. Sia i proteoglicani che il collagene sono attaccati alle proteine fibronectina, che, a loro volta, sono attaccate alle proteine integrali della membrana chiamate integrine.

Le integrine dei mammiferi sono recettori eterodimerici di adesione transmembrana comprendenti subunità glicoproteiche α e β. Diciotto diversi geni della catena α e otto diversi geni della catena β dimerizzano in varie combinazioni risultando in 24 tipi di integrine specifiche per i vertebrati. Attraversano la membrana e interagiscono con le proteine nel citosol e nell'ECM. La subunità α contiene un dominio della testa dell'elica β a sette pale mentre la subunità β ha un dominio della testa simile a I; insieme, legano il ligando. La testa di legame del ligando è collegata a due strutture simili a gambe, una per ciascuna subunità. La subunità β interagisce con la proteina citoscheletrica e aiuta a trasmettere segnali dentro e fuori la cellula.

Adattato dalla sezione 5.1 Componenti e struttura, 4.2 Tessuto epiteliale e 3.4 Caratteristiche uniche delle cellule eucariotiche, Openstax biology 2e

Integrine

Le cellule animali e protozoarie non hanno pareti cellulari per aiutare a mantenere la forma e fornire stabilità strutturale. Invece, queste cellule eucariotiche secernono un ...

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

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 to integral membrane proteins called integrins.

Integrins are heterodimeric transmembrane adhesion receptors in mammals. That means each receptor has two different glycoprotein subunits, an alpha subunit and a beta subunit. Eighteen alpha-chain genes and eight beta-chain genes can pair in different ways to make 24 vertebrate integrins.

These receptors span the cell membrane and link the ECM to the cytosol. The alpha subunit has a seven-bladed beta-propeller head domain, and the beta subunit has an I-like head domain. Together, these head domains bind ligand, and the two leg-like parts connect the head to the membrane.

The beta subunit also interacts with a cytoskeletal protein. This helps integrins transmit signals into and out of the cell. Their structure and connections make them important for adhesion and communication in cells that rely on the ECM.

Integrins in Cell Adhesion

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 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

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...

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

Learn how integrins connect the extracellular matrix to the cell membrane, support cell shape, and help transmit signals in animal and protozoan cells.

Integrins in Cell Adhesion | 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.

Integrins in Cell Adhesion

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