06/09 - RGD releases an interactive diagram page for the translation pathway

Translation pathway

Translation is the final stage of protein-coding gene expression. The genetic information encoded in the mature mRNA transcript is decoded into the polypeptide chain by the ribosome, a massive 80S ribonucleoprotein complex whose small 40S subunit is the mRNA decoder and the large 60S subunit carries out the peptidyl transferase reaction. Three steps are involved in the task: initiation, elongation and termination followed by the splitting of ribosomes and their recycling. Of these, the initiation pathway is the rate-limiting and the most regulated step. Initiation is intimately connected to the biogenesis of ribosomes as joining of the 60S subunit and formation of the elongation-competent 80S ribosome is subsequent to finding the initiation AUG codon by the methionine-tRNA-loaded preinitiation complex (PIC). Along the route, reactions and interactions, GTP hydrolysis and conformational changes mold the unfolding of translation pathways. Co-translational mRNA surveillance mechanisms are in place to rescue/recycle ribosomes aberrantly stalled due to structural features of mRNA, the presence of a premature stop codon or its absence in the mRNA sequence. Click here to explore the details of this complex system.