Insulin does not enter the cell that it affects. Instead, it starts a signal cascade within the cell. The signal culminates with the regulation of insulin-sensitive cytosolic enzymes and the transcription of specific nuclear genes that regulate metabolism.
Place the steps of the insulin signaling pathway that regulates gene transcription in the order in which they occur. Not all the steps will be placed.
a. Insulin binds its receptor.
b. INSR autophosphorylates.
c. INSR phosphorylates IRS1.
d. Grb2 assists the interaction between IRS1 and Sos.
e. Sos facilitates GDP release and GTP binding to Ras.
f. Ras activates the first of three protein kinases in a series.
g. Raf phosphorylates MEK, which activates ERK.
h. PKA activates downstream cytosolic enzymes.
i. PKB inactivates GSK3, thereby activating GS.
j. A protein kinase enters the nucleus.
k. Transcription factors activate.