GSE124290
CERES is an eIF4E-interacting protein that forms non-canonical translation initiation complexes and modulates translation during the diel cycle in plants
Translation is a fundamental step in gene expression that regulates multiple developmental and stress responses. One key step of translation is the association between eIF4E and eIF4G. This process is regulated in different eukaryotes by proteins which bind to eIF4E and block the formation of the eIF4E/eIF4G complex. Here, we report the discovery of CERES, the first functional eIF4E regulator described in plants. CERES is a modular protein that contains a LRR domain and a canonical eIF4E binding site (4E-BS), critical for CERES interaction with eIF4E in planta. CERES/eIF4E interaction excludes eIF4G from the complex. Despite this observation, CERES promotes translation in vivo interacts with eIF4A and with eIF3 in vivo and cosediments with translation initiation complexes in sucrose gradients. Moreover, ceres mutants display a sharp increase of the 80S peak and a reduction of polysome content at specific periods of the diel cycle. Super-resolution ribosome profiling demonstrates that these mutants show a change of translation efficiency of mRNAs related to light response and glucose management. Consistently, these mutants show a hypersensitive response to glucose. These data show that CERES is a “non canonical” translation initiation factor that, through the formation of alternative translation initiation complexes, modulates translation during the light cycle in plants. Overall design: Ribo-seq and RNA-seq of Arabidopsis Col-0 and ceres mutants. 3 replicates each.