eIF4E-independent translation is largely eIF3d-dependent

We study here how mRNAs are translated in an eIF4E1-independent manner by blocking eIF4E1 using a constitutively active version of eIF4E-binding protein (4E-BP). Via ribosome profiling we identify a subset of mRNAs that are still efficiently translated when eIF4E1 is inactive. We find that these mRNAs preferentially release eIF4E1 when eIF4E1 is inactive and bind instead to eIF3D via its cap-binding pocket. eIF3D then enables these mRNAs to be efficiently translated due to its cap-binding activity.