Why does the activation of a protein kinase that acts on initiation factor eIF2 block protein synthesis?
A)Phosphorylated eIF2 denatures.
B)Phosphorylated eIF2 cannot exchange its GDP for GTP, which is required for eIF2 to participate in another round of translation initiation.
C)Phosphorylated eIF2 cannot exchange its GTP for GDP, which is required for eIF2 to participate in another round of translation initiation.
D)Phosphorylated eIF2 is hyperactivated, blocking further translation.
E)Dephosphorylated eIF2 cannot exchange its GDP for GTP, which is required for eIF2 to participate in another round of translation initiation.

Question

Quizplus · Accepted Answer

When eIF2 is phosphorylated, it cannot exchange its GDP for GTP, which is required for eIF2 to participate in another round of translation initiation. Without the exchange of GDP for GTP, the initiation complex cannot form and protein synthesis is blocked.

Why Does the Activation of a Protein Kinase That Acts