Final answer:
The extracellular matrix (ECM) of animal cells is a network of proteins and carbohydrates, most notably collagen and proteoglycans, that supports cell structure and enables intercellular communication. Molecules in the ECM can bind to cell surface receptors, initiating signaling pathways affecting gene transcription and cellular activities.
Step-by-step explanation:
The extracellular matrix (ECM) of animal cells is a complex network of macromolecules, such as glycoproteins and collagen, that provides structural support to cells and facilitates intercellular communication. The most abundant protein within the ECM is collagen, which is intertwined with proteoglycans—carbohydrate-containing protein molecules. Together with other proteins like fibronectin and integrins, these components create a meshwork outside the plasma membrane. Integrins allow the ECM to communicate with the cell's internal cytoskeleton, transmitting signals that can influence cell behavior and function, including the transcription of specific DNA sections affecting protein production.
Cells within tissues are bound together via the ECM, which plays a crucial role in maintaining tissue integrity. Additionally, the ECM is vital for cells to communicate with each other and respond to external signals. This communication happens when molecules in the ECM bind to cell surface receptors, initiating structural changes that lead to chemical signaling inside the cell. These cellular responses include activating or deactivating the transcription of certain genes, thereby influencing the cell's activities.
Moreover, the ECM is significant for the resilience of tissues against external forces and is also a site where microbial pathogens may attach. For example, the pathogen Streptococcus pyogenes can bind to the ECM's fibronectin, assisting it in establishing infections such as strep throat.