Insulin-Like Growth Factor-I E-Peptide Activity Is Dependent on the IGF-I Receptor
Figure 3
E-peptide ERK signaling requires IGF-IR.
A. C2C12 cells were treated as in Figure 2, except the IGF-IR inhibitor NVPAEW541 (NVP, 100 nM) or DMSO was added to cells 90 minutes prior to and during stimulation for 20 minutes. Cells were treated with EA (1 µM), EB (10 nM), or recombinant IGF-I (IGF, 10 nM) as a positive control. EA and EB experiments were conducted separately, and image represents one sample from each experiment. B. Quantification of A. Data are presented as the effect of NVP on ERK phosphorylation: (P/T-ERK of NVP treated)/(P/T-ERK of DMSO treated cells). NoTx bands were used to compare between experiments. Bars represent means ± s.e.m. of N = 3 replicates. *, p<0.05 for comparisons of treatments to NoTx via 1-way ANOVA followed by a Tukey post-hoc test; †, p<0.05 for comparisons of NVP samples to their DMSO counterparts via student t-tests.
