Approaches have been developed for the kinetic dissection of eukaryotic translation initiation in vitro using rabbit reticulocyte ribosomes and a crude preparation of initiation factors. These new approaches have allowed the kinetics of formation of the 43S and 80S ribosomal complexes to be followed and have substantially improved the ability to follow formation of the first peptide bond. The r...

Eukaryotic translation initiation factor 3 (eIF3) is a central player in recruitment of the pre-initiation complex (PIC) to mRNA. We probed the effects on mRNA recruitment of a library of S. cerevisiae eIF3 functional variants spanning its 5 essential subunits using an in vitro-reconstituted system. Mutations throughout eIF3 disrupt its interaction with the PIC and diminish its ability to accel...

Proliferation and cell cycle progression in response to growth factors require de novo protein synthesis. It has been proposed that binding of the eukaryotic translation initiation factor 4E (eIF-4E) to the inhibitory protein 4BP-1 blocks translation by preventing access of eIF-4G to the 5' cap of the mRNA. The signal for translation initiation is thought to involve phosphorylation of 4BP-1, wh...

Eukaryotic translation initiation factor 3 (eIF3) is a multisubunit complex that plays a central role in translation initiation. We show that fission yeast Sum1, which is structurally related to known eIF3 subunits in other species, is essential for translation initiation, whereas its overexpression results in reduced global translation. Sum1 is associated with the 40S ribosome and interacts st...

All eukaryotic cellular mRNAs (except organellar) possess at their 5' end the structure m7GpppX (where X is any nucleotide) termed the "cap." The cap structure facilitates the melting of mRNA 5' secondary structure through the action of initiation factor-4F (eIF-4F) in conjunction with eIF-4B. eIF-4F consists of three subunits of which one, eIF-4E (eIF-4E has recently been designated eIF-4 alph...