And notice it exists in a specific type of conformation. And the conformation basically allows the movement of these calcium ions into this region of that transmembrane protein. Once the calcium moves in, this uses ATP, it hydrolyzes ATP that creates a conformational change. And now it traps that calcium and it opens up to the other side. And the calcium can now move onto this side, the other side of that membrane. And so in this way, these types of ptype ATPases can basically couple ATP.