Occludins are proteins that play a crucial role in the formation of tight junctions between cells. These tight junctions are essential for maintaining the integrity of cell layers, such as those found in epithelial and endothelial tissues. By sealing the spaces between adjacent cells, occludins help regulate the passage of substances, ensuring that only specific molecules can move between cells. In addition to their structural role, occludins are involved in signaling pathways that influence cell behavior and function. They contribute to the overall barrier function of tissues, protecting against unwanted substances and pathogens. Disruptions in occludin function can lead to various health issues, including inflammatory diseases and cancer.