Preface: the cellular communications maze.
Inter- and intracellular ionic and molecular communications are indispensable to the preservation of life and all organic functions. The cell constantly responds to a myriad of extracellular ionic and molecular signals, and cell behavior in single-cell or multicellular organisms is coordinated by these signals moving into, inside, or between the cells. The signals pass through the cell's phospholipidic plasma membrane by diffusion and, mostly, via protein transporters: gates, receptors, and/or ion pumps imbedded in the membrane. Each signaling pathway is a complex cause and effect chain of events involving intricate networks of interactions. For example, the extracellular signals, which are monitored by the cell's membrane cognate receptors, form ligand-receptor complexes. These are typically amplified by interaction with a coupling protein, mostly a G protein, and are diversified via intracellular signal transductions, either directly or via the activation of intracellular second messengers. The present volume focuses on signal-induced interactions that trigger specific responses of the effector system. Highlighting the cellular communication framework and the major parameters encountered in these complex interactive phenomena may help to familiarize the uninitiated with the complex phenomena involved in sustaining life.