eIF2A (eukaryotic translation initiation factor 2A), also known as CDA02, MSTP004 or MSTP089, is a 585 amino acid protein that contains three WD repeats. Expressed ubiquitously with highest expression in heart, brain, pancreas and placenta, eIF2A functions as a translation initiation factor that binds Met-tRNA and directs it to 40S ribosomal subunits. Present in the early steps of protein synthesis, eIF2A controls the binding of Met-tRNA to 40S ribosomal subunits in a codon-dependent manner, in contrast to the eIF2 complex which accomplishes the same task in a GTP-dependent manner. In addition to its role in transcription initiation, eIF2A may also act to negatively regulate the expression of specific proteins, suggesting a possible role as a transcriptional repressor. eIF2A exists as two isoforms due to alternative splicing events.
