Final answer:
The phosphorylation of eIF-2 prevents its binding with GTP, which is necessary for the formation of the initiation complex in protein synthesis. This leads to an impediment of protein synthesis, which is observed in increased levels in neurodegenerative diseases and could contribute to their progression.
Step-by-step explanation:
Regulation of Protein Synthesis via eIF-2 Phosphorylation
Protein synthesis, particularly during its initiation phase, is tightly regulated in cells. The eukaryotic initiation factor-2 (eIF-2) is a key player in this process. It binds to GTP and the small 40S ribosomal subunit, facilitating the start of translation. However, when eIF-2 is phosphorylated, it undergoes a conformational change that prevents it from binding GTP, halting the formation of the initiation complex. Consequently, this impairs the process of protein synthesis.
In the context of neurodegenerative diseases like Alzheimer's, Parkinson's, and Huntington's, the increased phosphorylation of eIF-2 could lead to a reduction in overall protein synthesis. This is because the phosphorylated eIF-2 is ineffective in forming the initiation complex, preventing the translation of mRNA into proteins. Therefore, increased eIF-2 phosphorylation is associated with a decrease in protein synthesis, potentially contributing to disease pathogenesis by disrupting the balance of protein production in neural cells.