Name: ecm proteins and cell signaling
Uploaded: 2023-04-30T11:54:04.000Z
Duration: 1 min 24 s
Channel: JoVE

Cells interact with a network of locally secreted molecules surrounding the plasma membrane, called the extracellular matrix or ECM.
These interactions are mediated by large multimolecular complexes called cell-matrix adhesion complexes that are broadly distributed or clustered in distinct patches on the plasma membrane called cell-matrix junctions.
Each adhesion complex comprises transmembrane receptors and cytosolic adaptor proteins that link the cytoskeletal filaments with ligands in the ECM.
Integrin, the most prominent adhesion receptor, and its adaptor talin can bind any of the three major classes of ECM molecules: proteoglycans, which cushion the cell; collagen, which provides mechanical strength; and multi-adhesive soluble proteins such as fibronectin that cross-link adhesion receptors with other matrix components.
Integrins bridge the cytoskeleton filaments with a specialized form of the ECM at the basal lamina lining the cell membrane&#39;s outer surface.
The resulting adhesion complex interacts with the ECM molecules and transmits mechanical and chemical signals to regulate cell growth, migration, and differentiation.

overview of cell-matrix interactions

Overview of Cell-Matrix Interactions

The extracellular matrix or ECM holds cells together to form a tissue and allows the cells within the tissue to communicate. ECM comprises proteins such as fibronectin, collagen, laminin, etc. The most abundant protein in this space is collagen. Collagen fibers are interwoven with carbohydrate-containing protein molecules called proteoglycans. ECM allows cell migration and provides a structural scaffold at cell adhesion that anchors the cell when the extracellular matrix proteins interact with transmembrane protein receptors.
An ECM ligand binds to the receptor and changes its conformation. The receptor, in turn, changes the conformation of the microfilaments positioned just under the plasma membrane.&#160; These conformational changes induce chemical signals within the cell that reach the nucleus and turn &#8220;on&#8221; or &#8220;off&#8221; the transcription of specific DNA sections, affecting the production of associated proteins, thus changing cellular activities.
Integrins are the most prominent transmembrane receptors that mediate cell-matrix junctions like focal adhesions and hemidesmosomes. On the cytosolic side, integrins bind to actin and intermediate filaments while they bind to fibronectin and collagen in the ECM face.
Adapted from section 5.1 Components and structure, 4.2 Epithelial tissue, and 3.4 Unique characteristics of eukaryotic cells, Openstax biology 2e

The extracellular matrix or ECM holds cells together to form a tissue and allows the cells within the tissue to communicate. ECM comprises proteins such ...

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JoVE Core

Cell Biology

Unit 1

Cell-Matrix Interactions

KEY TERMS AND CONCEPTS

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 adhesion. At these adhesion sites, ECM proteins connect with transmembrane protein receptors and help anchor the cell.

When an ECM ligand binds to a receptor, the receptor changes shape. This change also affects the microfilaments just under the plasma membrane. The shape changes trigger chemical signals inside the cell that travel to the nucleus. There, they can turn specific DNA sections on or off and change the proteins the cell makes.

These signals can alter cellular activities. Integrins are the main transmembrane receptors that mediate cell-matrix junctions such as focal adhesions and hemidesmosomes. On the inside of the cell, integrins bind to actin and intermediate filaments. On the ECM side, they bind to fibronectin and collagen.

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

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 the extracellular matrix supports tissues, anchors cells, and sends signals through integrins, collagen, fibronectin, and laminin.

ECM Proteins and Cell Signaling | 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.

ECM Proteins and Cell Signaling

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