Model of PERK pathway controlling rRNA transcription and translation in comparison to mTOR

Model of PERK pathway controlling rRNA transcription and translation in comparison to mTOR. (A) PERK pathway. Unfolded proteins in the ER lumen activate the PERK kinase. PERK phosphorylates eIF2α leading to inhibition of translation initiation and inhibition RRN3/TIF-IA activity, resulting in dissociation of RRN3/TIF-IA and Pol I from the preinitiation complex. Dashed lines indicate that direct interaction of components has not been demonstrated. (B) mTOR pathway. Under favorable conditions, signaling from growth factors and nutrients activates mTOR leading to phosphorylation of 4E-BP and S6K. Inhibition of 4E-BP and activation of S6K by mTOR phosphorylation cooperate to increase the efficiency of translation initiation. While the entire pathway has yet to be elucidated, mTOR and S6K activity lead to phosphorylation of rRNA transcription factors increasing transcription of rRNA.

Publication

Phosphorylation of Eukaryotic Translation Initiation Factor 2α Coordinates rRNA Transcription and Translation Inhibition during Endoplasmic Reticulum Stress . (2009) Jenny B. DuRose, et al. Mol Cell Biol. 2009 Aug;29(15):4295-4307. Figure: F7. All organisms Drosophila melanogaster Homo sapiens

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