Zinc inhibition of calmodulin: a proposed molecular mechanism of zinc action on cellular functions.

Calcium stimulates, and zinc inhibits, a wide variety of cell types. In the erythrocyte, we have found calcium and zinc to have antagonist actions in a variety of systems. An important mechanism for calcium effects on cells is activation of calmodulin. Calmodulin is a small ubiquitous protein which, when activated by calcium, has a large array of cellular regulatory functions. We now report that calmodulin function is inhibited by low concentrations of zinc. Zinc inhibition of calmodulin provides a rational molecular mechanism for the diverse cellular inhibitory effects of zinc, as well as for zinc's antagonism of calcium effects.