Dynamics of Eukaryotic Translation Initiation

Abstract

Temporally and spatially accurate protein synthesis is the key to maintain healthy cell physiology. The initiation phase of translation in eukaryotic organisms is the rate-limiting step in protein synthesis, where more than 20 polypeptides coordinate the assembly of an elongation-competent ribosomal complex on the mRNA template. Such a complex process is at the heart of translational control, and mis-regulation at this stage is linked to numerous human diseases including cancer. Unfortunately, our understanding of the mechanisms of initiation and its regulation is hindered by the lack of a dynamic picture the process. Here, we have developed in vitro single-molecule fluorescence methods to determine key compositional events and conformational dynamics during yeast translation initiation. We have fluorescently labeled mRNAs, tRNAs, protein factors and ribosomes to track initiation in real time. Our results provide a dynamic framework for better understanding translational control and regulation in eukaryotes.