Final answer:
Phosphorylation of eIF2 leads to inhibition of the formation of the initiation complex, causing a decrease in protein synthesis which may contribute to the pathologies observed in neurodegenerative diseases like Alzheimer's, Parkinson's, and Huntington's.
Step-by-step explanation:
When eIF2 becomes phosphorylated, it can have a significant impact on the process of protein synthesis. In its phosphorylated state, eIF2 binds to eIF2B, inhibiting its own exchange of GDP for GTP, which is a necessary step for the initiation of translation. Consequently, the initiation complex cannot form properly, leading to a general decrease in the rate of protein synthesis. This downregulation of protein synthesis conserves resources during stress conditions but can be problematic in diseases. For instance, an increase in phosphorylation levels of eIF2 is observed in neurodegenerative diseases such as Alzheimer's, Parkinson's, and Huntington's. In such cases, the phosphorylation likely contributes to the pathology of these diseases by inhibiting the synthesis of essential proteins.