Figure 4.

Inhibition of IGF-1R and IR phosphorylation in MCF-7 cells. MCF-7 cells were starved in serum free medium for 5 h, followed by addition of treatment medium with 1 nmol/L IGF-I or 5 nmol/L IGF-II with varying concentrations of s7g1 or 2g2. After cells were lysed, target proteins were immunoprecipitated by specific antibody conjugated resins. (A-B) Phosphorylation of IGF-1R induced by IGF-I or IGF-II was detected with a phosphor-tyrosine specific antibody. (C) Phosphorylation of IR induced by IGF-II was detected as following above methods. The total amount of IGF-1R or IR was detected by the same polyclonal antibody used for the immuneprecipitation. Data showed a representative from 3 separate experiments.