eIF-2

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eIF-2 (Eukaryotic Initiation Factor 2) is a heterotrimer of subunits alpha, beta, and gamma. eIF-2 mediates the binding of methionyl-tRNA_i^met to the ribosome in a GTP-dependent manner.

eIF-2 is released from the ribosome bound to GDP as an inactive binary complex.

To participate in another round of translation initiation, this GDP must be exchanged for GTP.

Under steady-state conditions of translation, eIF-2 must be recycled in order to participate in another round of translation initiation.

[edit] eIF-2B

Conversion of the inactive eIF-2-GDP to the active eIF-2-GTP form is catalyzed by a guanine nucleotide exchange factor, eIF-2B.

Phosphorylation of the alpha subunit of eIF-2 inhibits translation initiation by impairing the eIF-2B-catalyzed guanine nucleotide exchange reaction.

[edit] See also

• Eukaryotic initiation factors
• EIF-2 kinase

[edit] External links

• MeSH EIF-2
• Cap-dependent translation initiation from Nature Reviews Microbiology. A good image and overview of the function of initiation factors

v • d • e translation --> Initiation factors: Eukaryotic eIF1 (eIF1A), eIF-2, eIF3, eIF4A, eIF4B, eIF4E, eIF4G, eIF4F, eIF5

v • d • e GTP-binding protein regulators GTPase activating protein Chimerin 1 - RasGAP (Neurofibromin 1, IQ motif containing GTPase activating protein) Guanine nucleotide exchange factor EIF-2 - Son of Sevenless - Ras-GRF1 Other Guanosine nucleotide dissociation inhibitors