So once again, let's quickly review this pathway. So the first step is the binding of the primary messenger to the active side, not the active site, the location on that protein. And when that takes place, it initiates the removal of the GDP from this G protein and this GTP replaces it. And once that takes place, this structure is basically dissociated, it goes on and binds onto the phospholipac, which stimulates this enzyme to cleave the Pip two. And once the pip two is cleaved into two structures, the Dag and the IP three, these are the secondary messenger molecules. IP three goes on and binds onto this calcium channel, opens the calcium channel up and allows the movement of these calcium ions from the lumen of the Er into the cytoplasm.