[Levels of calmodulin and changes in cell physiology]

Calmodulin is a calcium-dependent regulator protein which activates about thirty enzymatic systems. Its intracellular levels, as well as the distribution between cytosolic and membrane fractions, are dependent on chemical (metal ions) and biological agents (hormones, viruses). The changes in levels are particularly pronounced after the cell transformation. The influence of transformation and the effect of chemical/biological agents are discussed separately as are the analytical methods for calmodulin determination. A detailed mechanism of action of chemical and biological agents on calmodulin levels is not yet known.