Extracellular matrix

The extracellular matrix (ECM) is a complex network of proteins and carbohydrates that provides structural and biochemical support to surrounding cells. It is a critical component of all tissues and organs in the body, influencing their development, function, and repair.

Structure

Diagram of the extracellular matrix components.

The ECM is composed of a variety of macromolecules, including collagen, elastin, glycoproteins, and proteoglycans. These components are secreted by cells and assemble into a three-dimensional network that fills the spaces between cells.

Collagen

Collagen is the most abundant protein in the ECM, providing tensile strength and structural integrity. It forms fibrils and fibers that are essential for the mechanical properties of tissues.

Elastin

Elastin is a key component of tissues that require elasticity, such as the skin, lungs, and blood vessels. It allows tissues to resume their shape after stretching or contracting.

Glycoproteins

Glycoproteins, such as fibronectin and laminin, play crucial roles in cell adhesion, migration, and differentiation. They serve as binding sites for cells and other ECM components.

Proteoglycans

Proteoglycans are composed of a core protein with covalently attached glycosaminoglycan (GAG) chains. They are involved in regulating the movement of molecules through the ECM and modulating cell signaling.

Functions

The ECM is not just a passive scaffold; it actively influences cell behavior and tissue function.

Structural Support

The ECM provides a physical framework that supports the shape and organization of tissues. It helps maintain the structural integrity of tissues under mechanical stress.

Cell Signaling

The ECM interacts with cell surface receptors, such as integrins, to influence cell signaling pathways. These interactions can affect cell proliferation, differentiation, and survival.

Tissue Repair

During tissue repair, the ECM undergoes remodeling to accommodate new tissue formation. It provides a scaffold for cell migration and proliferation during wound healing.

Barrier Function

The ECM acts as a barrier to the movement of cells and molecules, helping to compartmentalize tissues and maintain homeostasis.

Pathology

Alterations in the ECM can lead to various diseases, including fibrosis, cancer, and osteoarthritis. In fibrosis, excessive ECM deposition leads to tissue scarring and impaired function. In cancer, changes in the ECM can promote tumor progression and metastasis.

Related pages

• Cell adhesion
• Tissue engineering
• Fibrosis
• Cancer