Question

In exercising muscle, glycogen degradation supplies the muscle with glucose‑6‑phosphate. In order to stimulate muscle glycogen degradation, protein phosphatase 1 (PP1) must be inhibited. Four of the five events are involved in the inactivation of PP1 in exercising muscle. Which event is not involved?

a. Epinephrine initiates a signal transduction cascade that utilizes protein kinase A.

b. Phosphorylated PP1 inhibitor binds to PP1, facilitating glycogen degradation by phosphorylase a.

c. Protein kinase A phosphorylates GM in the GM-PP1 complex, resulting in its dissociation.

d. Insulin initiates a protein kinase cascade that utilizes glycogen synthase kinase.

e. Protein kinase A phosphorylates an inhibitor of PP1.

Answer 1

Answer:

The correct answer is d Insulin initiates a protein kinase cascade that utilizes glycogen synthase kinase.

Explanation:

During muscle contraction glycogen degradation occur which result in the formation of glucose-6-phosphate that is supplied to the muscle.This total phenomenon is signaled by steroid hormone epinephrine that deals with the breakdown of glycogen.

   But the peptide hormone insulin exhibit the opposite effect that to stimulate glycogen synthesis by activating the catalytic activity of glycogen synthase through the help of phosphorylation by glycogen synthase kinase.