Eukaryotic translation initiation factor 3 subunit J （EIF3J） is a member of the EIF-3 subunit J family. EIF3 has a crucial role in binding of initiator methionyl-tRNA and mRNA to the 40S ribosomal subunit to produce the 40S initiation complex. EIF3J binds to the aminoacyl （A） site and mRNA access channel of the 40S subunit， setting EIF3J directly in the ribosomal decoding center. In addition， EIF3J interacts with eIF1A and reduces 40S subunit affinity for mRNA. An elevated affinity for mRNA is restored upon enlistment of initiator tRNA， despite the fact EIF3J remains in the mRNA-binding cleft in the presence of tRNA.
