Junctional adhesion molecules (JAMs) are a group of proteins that play a crucial role in the formation and maintenance of tight junctions between cells. These proteins help to regulate the permeability of cell layers, ensuring that substances can pass through selectively. JAMs are important for maintaining the integrity of tissues and are involved in various biological processes, including inflammation and immune responses. JAMs are found in various tissues, including the endothelium of blood vessels and epithelial layers. They interact with other adhesion molecules and signaling pathways to facilitate cell communication and adhesion. Dysregulation of JAMs can contribute to diseases such as cancer and autoimmune disorders.