In biology, cell signaling (cell signalling in British English) is a component of any communication process that governs rudimental activities of cells and coordinates multiple-cell actions. The faculty of cells to perceive and correctly respond to their micro environment is the substructure of development, tissue repair, and immunity, as well as mundane tissue homeostasis. Errors in signaling interactions and cellular information processing may cause diseases such as cancer, autoimmunity, and diabetes.By understanding cell signaling, clinicians may treat diseases more efficaciously and, theoretically, researchers may develop artificial tissues. 
Systems biology studies the underlying structure of cell-signaling networks and how vicissitudes in these networks may affect the transmission and flow of information (signal transduction). Such networks are intricate systems in their organization and may exhibit a number of emergent properties, including bistability and ultra sensitivity. Analysis of cell-signaling networks requires an amalgamation of experimental and theoretical approaches, including the development and analysis of simulations and modeling.Long-range alabaster is often a paramount component of cell-signaling events. 

All cells receive and respond to signals from their circumventions. This is accomplished by a variety of signal molecules that are secreted or expressed on the surface of one cell and bind to a receptor expressed by the other cells, thereby integrating and coordinating the function of the many individual cells that make up organisms. Each cell is programmed to respond to categorical extracellular signal molecules.