What are the intercellular connections made of proteins known as?

• A. Desmosomes
• B. Gap junctions
• C. Tight junctions
• D. Adherens junctions

Answer: (A)

Intercellular connections composed of proteins that help to anchor adjacent cells together are known as desmosomes. These structures are crucial in providing mechanical stability to tissues, particularly in areas that experience significant stress and strain, such as the skin and cardiac muscle. Desmosomes consist of dense protein plaques that are found on the inner side of the plasma membrane, with cadherin-type proteins extending into the intercellular space to bind to cadherins on the adjacent cell.

Desmosomes support the structural integrity of tissues by distributing tensile forces across a cell layer, which prevents the separation of cells during mechanical challenges. This property is particularly vital in epithelial cells and is essential for their role as protective barriers.

Other types of intercellular connections, such as gap junctions, facilitate communication between cells through interconnecting channels, tight junctions create a seal to prevent leakage of molecules between cells, and adherens junctions provide additional adhesive connection while linking to the actin cytoskeleton. However, it is desmosomes that specifically serve to structurally couple cells together to withstand mechanical stress.