 eIF2 mediates the binding of tRNAiMet to the ribosome in a GTP-dependent manner.eIF2 is a heterotrimer consisting of an alpha (also called subunit 1, EIF2S1), a beta (subunit 2, EIF2S2), and a gamma (subunit 3, EIF2S3) subunit.Once the initiation phase has completed, eIF2 is released from the ribosome bound to GDP as an inactive binary complex.