And in this particular stigma transduction pathway, the target protein is phosphorolase kinase. So remember from a previous discussion that phosphorase kinase must be activated by two different factors. One is phosphorylation and the other one is calcium. So let's focus on the phosphorylation for just a moment. So we have PKA, which is activated by the binding of cyclic Amp, goes on and activates phosphorylase kinase. And what phosphorase kinase does is it goes on and activates Glycogen phosphorase.