Calmodulin mediates the control of a large number of enzymes, ion channels and other proteins by Ca(2+). Among the enzymes to be stimulated by the calmodulin-Ca(2+) complex are a number of protein kinases and phosphatases. High expression of PCM5 and 8 in stolon tips and stems, moderate in roots, and low in leaves. Steady-state expression of PCM6 in all the tissues tested, except in the leaves where the expression is lower. Expression of PCM5 and 8 reduced during tuber development. PCM5, PCM6 and PCM8 are not induced by touching. The expression of PCM7 was not investigated. This protein has four functional calcium-binding sites. Belongs to the calmodulin family.