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

As células se conectam com o ECM e outras células por meio de diferentes complexos de adesão, chamados coletivamente de junções de ancoragem.
Nas células epiteliais, aderências focais e hemidesmossomos conectam filamentos de actina e filamentos intermediários a uma forma especializada de ECM chamada lâmina basal.
Os hemidesmossomos contêm uma placa densa no lado citosólico da membrana plasmática formada pela proteína citolinker plectina.
Os filamentos intermediários contendo queratina estão conectados a esta placa por meio de alfa, seis, beta, quatro integrinas e outras proteínas, como BP230 e BP180.
Na face da MEC, as integrinas se ligam à laminina, uma glicoproteína que é um componente importante da lâmina basal.
Os hemidesmossomos resultantes podem transmitir sinais de ECM ajudando a célula a responder a forças mecânicas e mudar a forma, polaridade e direção da migração.

<ol>
	<li>Wei, Qi e Hayden Huang. "Insights sobre o papel das junções célula-célula na fisiologia e na doença." Revisão internacional de biologia celular e molecular 306 (2013): 187-221.</li>
	<li>Seetharaman, Shailaja e Sandrine Etienne-Manneville. "Diafonia do citoesqueleto na migração celular." Tendências em Biologia Celular 30, nº 9 (2020): 720-735.</li>
	<li>https://www.mechanobio.info/what-is-mechanosignaling/what-are-cell-cell-adhesions/what-are-anchoring-junctions/</li>
</ol>

junções de ancoragem

Anchoring Junctions

As junções de ancoragem são complexos multiproteicos que ajudam as células a se conectarem a outras células e à matriz extracelular. As junções de ancoragem estão presentes nas superfícies laterais e basais das células, proporcionando conexões fortes e flexíveis. As adesões focais são frequentemente formadas devido a interações celulares com os substratos da MEC, que iniciam a transdução de sinal através de cascatas de quinases e outros mecanismos. Juntos, eles proporcionam estabilidade e integridade dos tecidos. Existem três tipos de junções de ancoragem: desmossomos, hemidesmossomos e aderentes. Os desmossomos aparecem como placas densas, simétricas e em forma de disco na membrana celular. As proteínas de adesão chamadas caderinas estão envolvidas na formação de placas. A aparência distinta se deve às proteínas estruturais na superfície interna da membrana celular. Os hemidesmossomos se parecem com meio desmossomos e ligam as células à lâmina basal. Embora semelhantes em aparência aos desmossomos, eles incluem proteínas de adesão chamadas integrinas, em vez de caderinas. Essas conexões são essenciais para manter as células unidas. As junções aderentes usam caderinas ou integrinas, dependendo se elas se ligam a outras células ou à matriz. As junções são caracterizadas pela presença da proteína contrátil actina localizada na superfície citoplasmática da membrana celular. A actina pode conectar manchas isoladas ou formar uma estrutura semelhante a um cinto dentro da célula. As três junções de ancoragem influenciam a forma e o dobramento do tecido epitelial. Adaptado da seção 4.2 Tecido epitelial - Anatomia e Fisiologia 2 e, Openstax

Junções de Ancoragem

As junções de ancoragem são complexos multiproteicos que ajudam as células a se conectarem a outras células e à matriz extracelular. As junções de ancoragem estão presentes no ...

Education

JoVE Core

Cell Biology

Biologia Celular

Unit 1

Unidade 1

Cell-Matrix Interactions

Interações Célula-Matriz

KEY TERMS AND CONCEPTS

TERMOS-CHAVE E CONCEITOS

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 - Biologia Celular ilustra processos celulares complexos em vídeos de animação fáceis de entender e, ao mesmo tempo, abrangentes. Esta coleção foca nos componentes e funções essenciais das células, incluindo organelas e membranas, transporte celular e energia celular. É complementado por vídeos de Cientistas em ação que demonstram a aplicação da biologia celular em experimentos de pesquisa do mundo real.

Cell Adhesion in Anchoring Junctions

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