CAM KINASE-II AS FREQUENCY DECODER OF CA2+ OSCILLATIONS

In many cell types, Ca2+ signals are organized in the form of repetiti ve spikes. The frequency of these intracellular Ca2+ oscillations incr eases with the level of stimulation, suggesting the existence of a fre quency encoding phenomenon. The question arises as to how the frequenc y of Ca2+ oscillations can be decoded inside the cell. Ca2+/calmodulin kinase II has long been proposed as an attractive candidate, as it is a key target of Ca2+ signals. By immobilizing the Ca2+/calmoduiin kin ase II and subjecting it to pulses of Ca2+ of variable amplitude, dura tion, and frequency, De Koninck and Schulman((1)) have shown for the f irst time that the autonomous activity of Ca2+/calmodulin kinase II is highly sensitive to the temporal pattern of Ca2+ oscillations. BioEss ays 20.607-610, 1998. (C) 1998 John Wiley & Sons, Inc.