eEF1A

eEF1A, or eukaryotic elongation factor 1A, is a highly conserved GTP-binding protein that mediates the delivery of aminoacyl-tRNA to the ribosome during the elongation phase of cytosolic protein synthesis in eukaryotic cells. In the canonical cycle, eEF1A binds GTP and an appropriate aminoacyl-tRNA to form a ternary complex that associates with the ribosome A site. After correct codon–anticodon pairing and peptide bond formation, GTP is hydrolyzed, and eEF1A–GDP is released and subsequently recharged with GTP by the guanine nucleotide exchange factor eEF1B.

In vertebrates, eEF1A exists as two paralogs, eEF1A1 and eEF1A2. eEF1A1 is expressed broadly and is generally considered essential for viability, while eEF1A2 expression is developmentally regulated and enriched in neurons and muscle. Misregulation or ectopic expression of eEF1A2 has been observed in certain cancers, highlighting a potential role in disease contexts.

Beyond its role in translation, eEF1A participates in a variety of noncanonical functions. It can bind filamentous actin and influence cytoskeletal organization, and it has been implicated in RNA metabolism and cellular signaling pathways. These additional interactions reflect the protein’s involvement in broader aspects of cell biology, making it a focus of research in both basic and medical sciences.

eEF1A belongs to the GTPase superfamily and serves as the eukaryotic counterpart to bacterial EF-Tu. Its conserved architecture supports a shared mechanism for delivering aminoacyl-tRNA during protein synthesis, while vertebrate paralogs and noncanonical roles add layers of functional complexity in higher organisms.