What type of molecules are affected by eIF2 phosphorylation?

The correct choice focuses on eIF2, or eukaryotic initiation factor 2, which plays a critical role in the initiation of protein synthesis. eIF2 is involved in the formation of the initiation complex that facilitates the binding of the ribosome to the messenger RNA (mRNA). The phosphorylation of eIF2 impacts its function significantly by altering its ability to exchange guanosine diphosphate (GDP) for guanosine triphosphate (GTP). This phosphorylation leads to a decrease in the availability of the active form of eIF2 and consequently reduces the overall rate of translation initiation.

The impact of eIF2 phosphorylation primarily affects the translation of mRNAs because it directly inhibits the recruitment of the ribosomal subunits needed for the translation process. As a result, mRNA translation can be downregulated in response to various stress conditions, ensuring that resources are allocated effectively within the cell.

While DNA and proteins are fundamental biological molecules, they are not directly influenced by eIF2 phosphorylation. DNA serves as the template for mRNA transcription, and proteins are the end products of translation that eIF2 helps initiate. Ribosomes, as the machinery executing translation, are dependent on eIF2's proper functioning but are not