A 27-year-old man with type 1 diabetes mellitus is brought to the emergency department after being found confused at home. He has had poor oral intake due to gastroenteritis. His friend reports he mistakenly took his usual dose of rapid-acting insulin but then did not eat. On arrival, he is diaphoretic and tremulous. Point-of-care glucose is 36 mg/dL. He is given intramuscular glucagon because IV access is initially difficult. Ten minutes later, his mental status improves.

Glucagon binding to its receptor in the liver triggers a signaling cascade that increases blood glucose and also promotes ketone production during fasting.

Which of the following intracellular changes most directly mediates glucagon-stimulated hepatic gluconeogenesis while simultaneously inhibiting hepatic glycolysis?