So remember, in our discussion of the epinephrine signaling pathway, we focused on the physiological effect of running away from an animal. We set a bear. And so we said that a kinase is used in this particular pathway, namely protein kinase A. Protein kinase A is activated by a secondary messenger molecule that we'll talk about in a moment, cyclic amp. And once the protein kinase A is activated, it goes on to activate affected molecules. For instance, enzymes which carry out the breakdown of Glycogen into glucose.