What happens immediately after insulin binds to the α-subunit of the insulin receptor?
A) It activates the adjacent tyrosine kinase (β-subunit)
B) It increases glucose uptake by the cell
C) It stimulates glucagon secretion by the α cells
D) It stimulates the synthesis of GLUT-4 (glucose transporter-4)
E) It transports the GLUT-4 protein to the cell membrane

Question

Quizplus · Accepted Answer

Insulin binding to the α-subunit of the insulin receptor causes a conformational change that activates the adjacent tyrosine kinase (β-subunit). This leads to autophosphorylation of the receptor and activation of downstream signaling pathways that ultimately result in increased glucose uptake by the cell. Thus, choice B is also partially correct, but the immediate event after insulin binding is the activation of the tyrosine kinase. Choices C, D, and E are not directly related to the immediate event after insulin binding to the α-subunit.

What Happens Immediately After Insulin Binds to the α-Subunit of the Insulin