AKT is constitutively phosphorylated in HS2 cells.

(A) 663 HS1 cells were either grown in the presence of 2 U/mL Epo and 10% serum or starved in Epo and serum for 4 hours before being stimulated with 10 U/mL Epo and/or serum. 10 μM LY294002 was added during the last starvation hour. (B) 606 HS2 cells were either grown in the presence or absence of 2 U/mL Epo and 10% serum or starved in Epo and serum for 4 hours before being hyperstimulated by 10 U/mL Epo and/or serum. 10 μM LY294002 was added during the last starvation hour. Cell lysates were subjected to immunoblotting with anti–phospho-AKT (A, B upper panels) and anti-AKT (A, B lower panels) antibodies. The positions of phosphorylated AKT (P-AKT) and AKT were indicated.