The function of AK2 in promoting cell growth and viability. A. SDS-PAGE (12.5% gel) showing the recombinant expression and purification of His-AK2 in E. coli. Lane 1, total proteins of E. coli without induction; lane 2, total proteins after induction by IPTG; lane 3, purified His-AK2; M, protein marker. B. MTT assay to examine the role of AK2 in cell growth and viability. Halicoverpa epidermal cells (HaEpi) were incubated in Grace’s medium containing different concentrations of His-AK2 (0.078, 0.313, 1.25, 5, and 20 μM) for 72 h. C. Western blot showing that His-AK2 entered the HaEpi cells. Lane 1, cells incubated without His-AK2; lane 2, PBS buffer from the supernatant after washing the His-AK2-incubated cells; lane 3, cells incubated with 5 μM His-AK2 for 48 h after washed by PBS. D. Immunocytochemistry to show the entered His-AK2 in the cells 48 h post incubation. The control is the normal cells without treatment.