Extracellular matrix

Extracellular matrix (ECM) is a three-dimensional network of extracellular macromolecules such as collagen, enzymes, and glycoproteins that provide structural and biochemical support to surrounding cells. Because multicellularity evolved independently in different multicellular lineages, the composition of ECM varies between multicellular structures; however, cell adhesion, cell-to-cell communication and differentiation are common functions of the ECM.

Composition

The ECM is composed of two main classes of biomolecules: Glycosaminoglycans (GAGs) and fibrous proteins. GAGs are polysaccharides that occupy most of the extracellular space and provide the ECM with its gel-like properties. Fibrous proteins, on the other hand, provide structural support. These include collagen, elastin, fibronectin, and laminin.

Functions

The primary role of the ECM is to support the cells within an organism's tissues. It does this by serving as a scaffold for growth and also by signaling to cells to direct their differentiation. The ECM also plays a crucial role in tissue repair, guiding the movement of cells to injury sites.

Clinical significance

Alterations in the ECM can contribute to a number of pathologies, including cancer and fibrosis. In cancer, changes in the ECM can affect cell proliferation, survival, and migration, contributing to tumor growth and metastasis. In fibrosis, excessive deposition of ECM components leads to scarring and organ dysfunction.

See also

• Cell adhesion
• Cell-to-cell communication
• Differentiation (biology)

References

Extracellular matrix Resources
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