Analysis of the basic mechanisms underlying the mitogenic effect of Smad7 in CRC cells showed that Smad7 knockdown causes phosphorylation of eukaryotic translation initiation factor 2α (eIF2α), a transcription factor that regulates cell cycle arrest, and consequent upregulation of activating transcription factor 4 (ATF4) and CCAAT/enhancer binding protein homology protein (CHOP) (98). Here, ATF4 is linked to colorectal carcinoma.