So we have point A and point B. And let's begin our discussion by focusing on point A. So in point A, we basically have that alpha G protein adenylit cyclist complex. And when this complex exists, as shown, that adenylate cyclists will basically continue transforming the ATP molecules into the cyclic Amp molecules, which are the secondary messengers in this Epinephrine pathway. So ultimately, what causes the alphagy protein to actually bind and stimulate that adenylate cyclist? Well, basically, it's the GTP.