Recent work has implicated eIF3 in the termination-reinitiation process [17] , which is of interest because eIF3 plays an important role in disassembly of ribosomes following the termination event which leaves the 80S ribosome with bound deacylated tRNA and still associated with the mRNA [37, 38] . At low (sub-optimal) Mg 2+ , this disassembly requires eIF1 and eIF3, but no other protein factor. First, eIF3 binds to the solvent face of the 40S subunit, promoting dissociation of the 60S subunit, and leaving the 40S subunit (with bound deacylated tRNA) still associated with the mRNA. Then eIF1 ejects the deacylated tRNA, while the eIF3j subunit promotes dissociation of the 40S/eIF1/eIF3 complex from the mRNA [37] . At higher, more physiologically relevant Mg 2+ , as would pertain in our translation assays, there is also a requirement for ABCE1 and ATP [38] , which catalyses the first step of dissociation of the ribosomal subunits, ejecting the 60S subunit and again leaving the 40S subunit (plus bound deacylated tRNA) still associated with the mRNA. Then eIF3 binds to the solvent face of the 40S subunit, thereby preventing any ribosomal subunit reassociation, and events thereafter are exactly as at low Mg 2+ [37, 38] .