Q. A 25-year-old woman presents to her primary care physician with a three-month history of excessive thirst, frequent urination, and weight loss. She reports that these symptoms have been progressively worsening and that she has been feeling more tired than usual. The patient's vital signs on presentation are BP 120/80 mm Hg, HR 80 beats/minute, and RR 16 breaths/minute. The physical examination reveals a patient with weight loss and signs of dehydration. Further evaluation reveals elevated levels of glucose in the patient's blood and a positive autoimmune screen for type 1 diabetes. The patient is started on insulin therapy to replace the missing insulin and to regulate her blood glucose levels. What is the signaling pathway of insulin?