AKT1 and cancer: Interestingly, whereas there was a dramatic decrease of phospho-AKT signal upon IRS4 deletion, we also observed evident elevation in phospho-ERK level in OVCAR-5 IRS4-KO cells (Figure 4F), indicating a potential compensatory effect of ERK signaling pathway which may contribute to the survival and proliferative capacities of OVCAR-5 cancer cells after IRS4 deletion.