But what happens when the epinephrine actually binds onto this location here? Well, as soon as that epinephrine binds, it creates conformational changes in this region of that seven TM domain, and that also creates conformational changes in the alpha domain. So essentially what happens is there's a constriction in the region that holds the GDP and that expels that GDP. And instead of having the GDP, there is a soluble GTP in solution inside the cytoplasm and goes on and binds onto a new location found in that alpha domain. And as soon as that alpha domain, the g alpha protein. So this is also known as the Galpha protein because the alpha domain is a g protein.