Again, when the calcium binds to the protein, it usually exposes hydrophobic regions of the protein. And we'll see why that's important in just a moment. But if that continues to happen for a very long period of time inside the cytoplasm that can be harmful. And so what the cell actually does is it uses these special membrane pumps, we call the calcium Atph to create electrochemical gradients, to basically pump these calciumines and store the calcium mines away from the proteins inside the cytoplasm. So we store these calciumines in the endoplasmic reticulum. And when we actually want to use the calcium ions, we have these membrane channels not shown diagram that can allow the movement of these calcium odds from the lumen into the cytoplasm of the cell.