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

Las integrinas son una familia de receptores de adhesión celular que se unen a ligandos en la matriz extracelular o ECM para mediar las adherencias célula-matriz.
Pasan de un estado activo a uno inactivo. En la forma activa, sirven como enlazadores mecánicos que conectan el citoesqueleto con la matriz extracelular.
La integrina comprende subunidades de glicoproteína alfa y beta asociadas de forma no covalente, formando un heterodímero transmembrana.
La cola C-terminal intracelular de la subunidad beta interactúa con los filamentos de actina en el citosol a través de proteínas adaptadoras como la talina y la paxilina. Los grandes dominios extracelulares N-terminales de la integrina se unen a motivos específicos de secuencia de aminoácidos en las proteínas ECM, como la secuencia RGD en la fibronectina.
El complejo de adhesión formado transmite señales bidireccionalmente a través de la membrana plasmática con la ayuda de proteínas efectoras, lo que facilita la motilidad, el crecimiento y la supervivencia de las células.

<ol>
	<li>David G. Menter, Raymond N. DuBois, "Prostaglandinas en la adhesión, migración e invasión de células cancerosas", International Journal of Cell Biology, vol. 2012, ID de artículo 723419, 21 páginas, 2012. https://doi.org/10.1155/2012/723419</li>
	<li>Humphries, J. D., Byron, A., & Humphries, M. J. (2006). Los ligandos de integrinas de un vistazo. Revista de ciencia celular, 119(19), 3901-3903.</li>
	<li>Humphries, M. J. (2000). Estructura de la integrina. Transacciones de la Sociedad Bioquímica, 28(4), 311-340.</li>
</ol>

integrinas

Integrins

Las células animales y protozoarias no tienen paredes celulares que ayuden a mantener la forma y proporcionen estabilidad estructural. En cambio, estas células eucariotas secretan una masa pegajosa de carbohidratos y proteínas en los espacios entre las células adyacentes. Esta red de proteínas y moléculas se llama matriz extracelular o ECM.

Algunas proteínas de la MEC se ensamblan en una membrana basal a la que se adhieren los componentes restantes. Los proteoglicanos suelen formar la mayor parte de la MEC, mientras que las proteínas fibrosas, como el colágeno, proporcionan resistencia. Tanto los proteoglicanos como el colágeno están unidos a proteínas fibronectina, que, a su vez, están unidas a proteínas integrales de membrana llamadas integrinas.

Las integrinas de mamíferos son receptores de adhesión transmembrana heterodiméricos que comprenden subunidades de glicoproteínas α y β. Dieciocho genes diferentes de la cadena α y ocho genes diferentes de la cadena β se dimerizan en diversas combinaciones, lo que da como resultado 24 tipos de integrinas específicas de los vertebrados. Abarcan la membrana e interactúan con proteínas en el citosol y la ECM. La subunidad α contiene un dominio de cabeza de hélice β de siete palas, mientras que la subunidad β tiene un dominio de cabeza tipo I; juntos, se unen al ligando. La cabeza de unión del ligando está conectada a dos estructuras en forma de patas, una de cada subunidad. La subunidad β interactúa con la proteína citoesquelética y ayuda a transmitir señales dentro y fuera de la célula.

Las células animales y protozoarias no tienen paredes celulares que ayuden a mantener la forma y proporcionar estabilidad estructural. En cambio, estas células eucariotas secretan un ...

Education

Educación

JoVE Core

Cell Biology

Biología Celular

Unit 1

Unidad 1

Cell-Matrix Interactions

Interacciones célula-matriz

KEY TERMS AND CONCEPTS

TÉRMINOS Y CONCEPTOS CLAVE

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 Biología Celular ilustra procesos celulares complejos mediante completos vídeos animados fáciles de entender. Esta colección se centra en los componentes esenciales de las células y su funcionamiento, incluyendo los orgánulos y las membranas, el transporte celular y el metabolismo energético celular. Todo este material se complementa con los vídeos de científicos en acción, que muestran la aplicación de la biología celular en experimentos reales de investigación.

Integrins in Cell Adhesion

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