Translation Initiation in Eukaryotes: Factors and Mechanisms

Translation initiation, the first stage in protein synthesis, is the process of assembly of large (60S) and small (40S) ribosomal subunits to form an 80S ribosome containing initiator transfer RNA (tRNA) (Met-tRNA i Met ) that is base paired to the initiation codon of a messenger RNA in the ribosomal peptidyl (P) site. This process is mediated by at least 11 eukaryotic initiation factors and proceeds via the sequential formation of intermediate complexes. Initiation is the rate limiting step of translation, and is a major focus for pathways that regulate gene expression.