A series belоw is аn оverview оf the epinephrine signаling cаscade discussed in your resources. What is the receptor? Epinephrine binds to a G-protein coupled receptor (GPCR). GPCR activates a G-protein. G protein activates adenlyl cyclase. Adenylyl cyclase makes cyclic AMP. Cyclic AMP activates protein kinase A. Protein kinase A activates phosphorylase kinase. Phosphorylase kinase activates glycogen phosphorylase. Glycogen is broken down to be used as individual glucose molecules.