Which junction type provides strong adhesion and resists mechanical stress?

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

Answer: (D)

Desmosomes provide the strongest adhesion under mechanical stress because they are built to anchor cells together and distribute pulling forces across a network of intermediate filaments. The extracellular cadherin proteins in desmosomes (desmogleins and desmocollins) from neighboring cells bind tightly, forming a strong adhesive junction. Inside the cell, plaque proteins such as desmoplakin, plakoglobin, and plakophilin connect these cadherins to keratin intermediate filaments, creating a robust cytoskeletal network that spreads tension across many cells. This arrangement lets tissues—like skin and heart muscle—resist tearing when stretched. Adherens junctions also provide cell–cell adhesion but couple to actin filaments and are more about maintaining tissue integrity under flow and shape changes, not as specialized for bearing high mechanical load. Tight junctions seal spaces between cells, and gap junctions permit intercellular communication, neither of which provide strong mechanical adhesion.