Insulin Signaling on Glucose Metabolism

Practice: Place the following insulin signaling transduction events in order of occurrence (event 9 is provided).

a) Full activation of PKB/Akt ______.

b) Activated PI3K converts PIP₂ to PIP₃ ______.

c) GLUT4 expressed in the cell membrane ___9___.

d) Ligand/insulin binding to the insulin receptor ______.

e) GSK3 is phosphorylated & inactivated ______.

f) Activated PDK1 phosphorylates & activates of PKB/Akt ______.

g) IRS-1 is phosphorylated & activated by the insulin receptor ______.

h) Autophosphorylation of the insulin receptor ______.

i) PI3K is activated upon its SH2 domain binding phosphorylated IRS-1 ______.

j) Glycogen synthase converts glucose to glycogen ______.

k) PIP₃ molecules laterally diffuse to bind PKB/Akt & PDK1 ______.

Practice: All of the following are true of the reaction catalyzed by PI3K EXCEPT:

Practice: Which of the following results would you predict to occur if a mutation changes a Tyr residue of the Insulin Receptor to Ala?

Practice: IRS-1 is an essential adaptor protein in the insulin signaling pathway. If IRS-1 was under expressed in muscle cells, what effect would you expect to see on glycogen synthesis?