IRS4 and ovarian carcinoma: Taken together, both PUP-IT assay and biochemical pull down assay consistently demonstrated that FER-mediated tyrosine phosphorylation of IRS4 at Tyr779 enhanced the recruitment of PIK3R2 and activation of the PI3K-AKT signaling pathway, providing new insights into signaling events that underlie cell proliferation in ovarian carcinoma cells.