Indirect inactivation of eukaryotic initiation factor 2 in reticulocyte lysate by selenite.

摘要: Abstract Addition of selenite to rabbit reticulocyte lysate produces a biphasic pattern translational inhibition. Sucrose density gradient shows that the onset inhibition is accompanied by decreased Met-tRNAf binding 43 SN ribosomal subunits and loss polysomes. Control rates translation are restored addition exogenous eukaryotic initiation factor 2 (eIF-2). Selenite also directly inhibits activity eIF-2. While could react with unpaired cysteine residues eIF-2 inhibit protein synthesis initiation, more complex mechanism than direct inactivation suggested following observations: 1) produced an apparent increase in phosphorylation state eIF-2alpha; 2) extent inhibiton not proportional steady-state level phosphorylation. Rather, time required for decreases as eIF-2alpha increased. This suggests multistep sequence inactivation, dependent upon initial activation kinase followed additional modification(s).