Answer:
D. 4E-BP1 binding to elF4E prevents loading of the mRNA onto the ribosome.
Explanation
In eukaryotic organisms, the eIF4E translation initiation factor functions by directing the ribosomes to the 5'-terminal cap structure of the messenger RNA (mRNA) in order to start the translation. Moreover, phosphorylation is a posttranslational modification of specific amino acids on proteins that play diverse cellular functions by altering protein stability, location, and/or enzymatic activity. It has been shown that elF4E phosphorylation is increased in response to cellular stimuli that induce translation in the ribosomes (e.g., growth factors, hormones, etc). The eukaryotic translation initiation factor 4E (eIF4E)-binding protein 1 (4E-BP1) is a repressor of mRNA translation which is phosphorylated and inactivated by growth factors and hormones, thereby inhibiting 4E-BP1 binding to elF4E and consequently activating translation.
