You are utilizing a cell culture system derived from a breast cancer tumor to examine the process of protein synthesis. You discover that these cells do not effectively generate the GTP-bound form of the translation initiation factor, eIF-2. Which of the following translation factors is most likely to be defective in these cells, thereby impairing the GDP for GTP exchange in eIF-2?
A) eIF-1
B) eIF-2B
C) eIF-4A
D) eIF-4E
E) eIF-4G

Question

Quizplus · Accepted Answer

eIF-2B is the translation factor responsible for the GDP for GTP exchange in eIF-2.  The eIF-2 cycle involves the regeneration of GTP-bound eIF-2 following the hydrolysis of GTP during translational initiation. When the 40S preinitiation complex is engaged with the 60S ribosome to form the 80S initiation complex, the GTP bound to eIF-2 is hydrolyzed providing energy for the process. In order for additional rounds of translational initiation to occur, the GDP bound to eIF-2 must be exchanged for GTP. This is the function of eIF-2B

You Are Utilizing a Cell Culture System Derived from a Breast