Now, the first thing we should notice is if we compare the concentration of calcium ions on the inside the cytoplasm to, let's say, the outside or even the lumen, we'll see that inside the cytoplasm, we have a very low concentration of calcium ions. The question is why? Well, to answer the question, let's recall a bit of general chemistry. So we know that when calcium binds to things like proteins, it creates conformational changes in the proteins, and that exposes hydrophobic regions of the protein to the aqueous environment. And what that means is the calcium protein complexes, for the most part, become insoluble in that aqueous environment. And so what that can lead to is precipitation.