The insulin receptor is a transmembrane protein that plays a role in the regulation of glucose homeostasis. The receptor’s extracellular domain binds specifically to the peptide hormone insulin. The receptor’s intracellular domain interacts with cellular factors. The binding of insulin to the receptor stimulates a signal transduction pathway that results in the subcellular translocation of GLUT4, a glucose transport protein that is stored in vesicles inside the cell. A simplified model of the insulin receptor–signaling pathway is shown in Figure 1.
Which of the following statements best predicts the effect of a loss of function of the insulin receptor’s intracellular domain?
answer choices
The stimulation of the signal transduction pathway will increase.
The storage of GLUT4 in vesicles inside the cell will increase.
The number of GLUT4 molecules in the plasma membrane will increase.
The concentration of glucose inside the cell will increase.