Which of the following steps amplify the epinephrine signal...

Which of the following steps amplify the epinephrine signal response in cells? 1. receptor activation of G protein 2. G protein activation of adenylyl cyclase 3. cAMP activation of PKA 4. PKA phosphorylation of glycogen phosphorylase kinase (GPK) 1 and 3 1 and 4 1, 3, and 4 2, 3, and 4

Question 11 (3 points) Several steps are involved in the mobilization of glycogen reserves in the liver cell in response to the hormone epinephrine. Place the following in the correct order: Epinephrine binds to a target receptor protein in the cell membrane. The activated receptor stimulates a trimeric G protein (Gs). The alpha-subunit of Gs is stimulated to exchange GTP for GDP. The trimeric G protein dissociates into Gsbg and Gsa-GTP subunits. The Gsa-GTP subunit activates adenylyl cyclase to produce cAMP. Two cAMP bind to each regulatory domain of protein kinase A, freeing (activating) the catalytic subunits. Active protein kinase A phosphorylates several target proteins, including glycogen phosphorylase kinaseb. Glycogen phosphorylase kinasea phosphorylates glycogen phosphorylaseb. Glycogen phosphorylasea mobilizes the glycogen reserves.

Adi S.