Shooting from the hip: spatial control of signal release by intracellular waves.

Abstract

The versatility of cell–cell communication relies on sophisticated modules for signal generation, transmission, detection, and processing (1). Compared with signal detection and intracellular processing, signal release is relatively poorly understood. For instance, even though the epidermal growth factor receptor (EGFR) signaling network has been extensively studied over the past 4 decades, the molecules that mediate release of EGFR ligands are being identified only now (2–5). The outstanding issues in signal release are similar to the ones studied in the context of signal detection and processing (6). What are the basic patterns in the dynamic release of small molecules, ions, and hormones? What are the constraints on the time scales of signal release imposed by the corresponding time scales of the signal transmission and detection? Finally, can a cell point its signals toward its neighbors, in a way similar to aiming a gun at a target or to directing electromagnetic and acoustic signals in man-made communications networks?