DAP5

DAP5, short for death-associated protein 5, is a protein encoded in humans by the EIF4G2 gene. It is a member of the eukaryotic translation initiation factor 4G (eIF4G) family and is also referred to as eIF4G2 or p97 due to its approximate molecular weight. Like other eIF4G proteins, DAP5 functions as a scaffold in translation initiation, coordinating the assembly of initiation factors on messenger RNA. However, it lacks the N-terminal eIF4E-binding site found in the canonical eIF4G1, and its N-terminal region shows divergence. As a result, DAP5 is thought to support cap-independent translation, particularly through internal ribosome entry sites (IRES) and under conditions when cap-dependent initiation is downregulated.

In cells, DAP5 interacts with components such as eIF3 and eIF4A to promote ribosome recruitment to select mRNAs. It participates in stress-responsive translation and can influence cellular survival in certain contexts. DAP5 is expressed broadly in human tissues, and alterations in EIF4G2 expression or function have been studied in relation to cancer and neurodegenerative diseases, as researchers investigate its role in selective translation during stress.

For nomenclature, DAP5 is widely used as an alias alongside EIF4G2 and p97. The protein is conserved across vertebrates and serves as a specialized translation initiation factor within the broader eIF4G family, complementing the cap-dependent functions of EIF4G1 with cap-independent activity on specific mRNAs.