Final answer:
Cadherins are proteins that form adherens junctions in animal cells, acting as cellular glue for strong tissue cohesion, especially in tissues subjected to stretching. They also play a role in cellular signaling and tissue development. Dysfunctions in cadherin-mediated junctions are commonly associated with cancer cell progression.
Step-by-step explanation:
Cadherins are a type of protein found in animal cells that are critical for the formation of adherens junctions (desmosomes). These proteins serve as cellular 'glue' that contributes to the tight connection and cohesion between cells, forming strong tissues. Desmosomes are specialized structures that behave like spot welds, providing mechanical strength to tissues that undergo stretching, such as skin, heart, and muscles. Cadherins, as part of the plasma membrane, interact with intermediate filaments inside the cell, providing a robust structural connection between adjacent cells. They are crucial for maintaining the structure and integrity of epithelial cell sheets, and their dysfunction is often related to cancer, where cells fail to form proper cell junctions, including gap junctions and desmosomes.
In addition to their structural role, cadherins are also involved in signaling pathways that regulate cell behavior, including cell movement and tissue organization during embryonic development. Cells use cadherins and integrins to interact with the extracellular matrix, facilitating migration and communication during tissue formation. Importantly, integrins are another family of proteins that mediate the attachment of cells to the extracellular matrix, but they are not the focus for cadherins. Gap junctions, on the other hand, allow direct communication between cells by permitting ions and small molecules to pass through connexon structures, distinct from the mechanical junctions formed by cadherins.