Systemic Reprogramming of Translation Efficiencies on Oxygen Stimulus

Publication date: Available online 4 February 2016
Source:Cell Reports
Author(s): J.J. David Ho, Miling Wang, Timothy E. Audas, Deukwoo Kwon, Steven K. Carlsson, Sara Timpano, Sonia L. Evagelou, Shaun Brothers, Mark L. Gonzalgo, Jonathan R. Krieger, Steven Chen, James Uniacke, Stephen Lee
Protein concentrations evolve under greater evolutionary constraint than mRNA levels. Translation efficiency of mRNA represents the chief determinant of basal protein concentrations. This raises a fundamental question of how mRNA and protein levels are coordinated in dynamic systems responding to physiological stimuli. This report examines the contributions of mRNA abundance and translation efficiency to protein output in cells responding to oxygen stimulus. We show that changes in translation efficiencies, and not mRNA levels, represent the major mechanism governing cellular responses to [O2] perturbations. Two distinct cap-dependent protein synthesis machineries select mRNAs for translation: the normoxic eIF4F and the hypoxic eIF4F^H. O2-dependent remodeling of translation efficiencies enables cells to produce adaptive translatomes from preexisting mRNA pools. Differences in mRNA expression observed under different [O2] are likely neutral, given that they occur during evolution. We propose that mRNAs contain translation efficiency determinants for their triage by the translation apparatus on [O2] stimulus.

Graphical abstract

Teaser

Ho et al. show that cells rely on a switch in mRNA translation efficiency, and not mRNA levels, to alter protein output on O2 stimulus. Two distinct cap-dependent protein synthesis machineries mediate this process: the normoxic eIF4F and the hypoxic eIF4F^H. The O2-regulated eIF4F and eIF4F^H generate complex and adaptive translatomes.


from #AlexandrosSfakianakis via Alexandros G.Sfakianakis on Inoreader http://ift.tt/1PWo51k
via IFTTT