28.1:
Overview of Cell-Matrix Interactions
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'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.
28.1:
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. These conformational changes induce chemical signals within the cell that reach the nucleus and turn “on” or “off” 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
Suggested Reading
- Vickerman, V., & Kamm, R. D. (2012). Mechanism of a flow-gated angiogenesis switch: early signaling events at cell-matrix and cell-cell junctions. Integrative Biology, 4(8), 863-874.
- Ding, H., Zhou, P., Fu, W., Ding, L., Guo, W., & Su, B. (2021). Spatially selective imaging of cell-matrix and cell-cell junctions by electrochemiluminescence. Angewandte Chemie International Edition, 60(21), 11769-11773.