Phosphorylation of eukaryotic initiation factor 2 during physiological stresses which affect protein synthesis.

摘要: Phosphorylation of the alpha subunit eukaryotic initiation factor 2 (eIF-2) is a major mechanism regulating protein synthesis in rabbit reticulocytes. To determine whether phosphorylation eIF-2 likely regulatory Ehrlich cell, we have measured percent cellular which phosphorylated cells exposed to heat shock, 2-deoxyglucose, or amino acid deprivation, conditions rapidly decrease concentration 40 S complexes and inhibit synthesis. eIf-2 (P) were separated by isoelectric focusing detected immunoblotting with monoclonal antibody developed for this purpose. Under above three inhibitory conditions, increased rapidly, increase correlated time rapid inhibition In heat-shocked returned 37 degrees C, both remained unchanged 10 min then toward control values slowly parallel. The close temporal correspondence between changes supports an important role An 25-35 percentage points, 50-60% from levels 20-30% phosphorylation, 80-100% This steep curve consistent saturates inhibits guanine-nucleotide exchange factor.