Eukaryotic initiation factor-2 (eIF-2)

Definition

Eukaryotic initiation factor-2 (eIF-2) is a protein complex essential for the initiation of mRNA translation in eukaryotic cells. It plays a critical role in the formation of the pre-initiation complex by binding GTP and the initiator tRNA, facilitating its attachment to the small ribosomal subunit.

5 Must Know Facts For Your Next Test

1. eIF-2 is composed of three subunits: α, β, and γ.
2. The activity of eIF-2 is regulated through phosphorylation, which inhibits its function and thus reduces protein synthesis.
3. eIF-2-GTP binds to the initiator methionine-tRNA (Met-tRNAi) to form a ternary complex.
4. Phosphorylation of eIF-2α at serine 51 is a key regulatory mechanism during cellular stress responses.
5. Malfunctions in eIF-2 regulation are linked to diseases such as cancer and neurodegenerative disorders.

Review Questions

• What are the three subunits that make up eIF-2?
• How does phosphorylation affect the function of eIF-2?
• Why is eIF-2 important for the initiation phase of translation?

Related terms

mRNA Translation: The process by which ribosomes synthesize proteins using mRNA as a template.

Ribosome: A molecular machine that facilitates the decoding of mRNA into polypeptides.

tRNA: Transfer RNA molecules that bring amino acids to ribosomes during protein synthesis.