Juxtacrine signalling (or contact-dependent signalling) is a type of cell–cell or cell–extracellular matrix signalling in multicellular organisms that requires close contact. In this type of signalling, a ligand on one surface binds to a receptor on another adjacent surface. Hence, this stands in contrast to releasing a signaling molecule by diffusion into extracellular space, the use of long-range conduits like membrane nanotubes and cytonemes.
In this type of signaling, a cell places a specific ligand on the surface of its membrane, and subsequently another cell can bind it with an appropriate cell surface receptor or cell adhesion molecule. An important example is the Notch signaling pathway, notably involved in neural development. In the Notch signaling pathway for vertebrates and Drosophila, the receiving cell is told not to become neural through the binding of Delta and Notch. Within the eye of vertebrates, which cells become optic neurons and which become glial cells is regulated by Notch and its ligands.
Cells use mainly the receptor integrin to interact with ECM proteins. Integrins are a family of receptor proteins that integrate the extracellular and intracellular structures, allowing them to perform together. See also Mechanotransduction
