43S complex Ceruloplasmin mRNA:eIF4F:eIF4B:eIF4H 43S: Ceruloplasmin mRNA:eIF4F:eIF4B:eIF4H:PABP Formation of translation initiation complexes yielding circularized Ceruloplasmin mRNA in a 'closed-loop' conformation Authored: Matthews, L, 2004-12-13 00:33:09 Edited: Matthews, L, 0000-00-00 00:00:00 Pubmed11058101 Pubmed9857202 Reactome Database ID Release 43156808 Reactome, http://www.reactome.org ReactomeREACT_1515 The precise order of events leading to the circularization of poly (A) mRNA during translation initiation is unknown. Here the association of PABP with the poly (A) mRNA and the association of PABP with eIF4F are represented as occuring simultaneously after formation of the initiation complex. However, it is also possible that these interactions occur during the formation of the translation initiation complex. The binding of eIF4F to the cap and binding of PABP to the poly (A) tail, for example, may occur at the same time. In fact, the eIF4G-PABP interaction helps eIF4F to bind tighter to the cap (Borman et al. 2000.) In addition, eIF4B and eIF4H bind more transiently to the mRNA and may not be part of an initial complex in which PABP has not yet touched eIF4G.