Figure 1: Treatment of HEK-293T cells with amino acids and insulin stimulates phosphorylation of 4E-BP1 at Thr37/46, as detected by PathScan ® Phospho-4E-BP1 (Thr37/46) Sandwich ELISA Kit #7216, but does not affect the level of total 4E-BP1 protein detected by Western analysis. HEK-293T cells (70-80% confluent) were starved overnight and deprived of amino acids for 1 hour. The amino acids were replenished for 1 hour. Cells were either untreated or stimulated with 100 nM insulin for 30 minutes at 37ºC. λ phosphatase treatement of control cell lysates (4000 U/mL for 60 minutes at 37ºC) abolishes the basal phosphorylation of 4E-BP1 as shown by both sandwich ELISA and Western analysis. The absorbance readings at 450 nM are shown in the top figure, while the corresponding Western blots, using 4E-BP1 Antibody #9452 (left panel) or Phospho-4E-BP1 (Thr37/46) Antibody #9459 (right panel), are shown in the bottom figure.
Figure 2: The relationship between the protein concentration of lysate from amino acid (AA)/untreated and AA/insulin-treated HEK-293T and the absorbance at 450 nM is shown.