IRS1 and colonic neoplasm: Phosphatidylinositol 3-kinase α (PI3Kα) is involved in cell proliferation forming interactions with adapter proteins such as insulin receptor substrate 1 (IRS1) in the presence of growth factor stimulation, stimulating the catalytic activity of PI3Kα.47 The two most common mutations found in cancer (E545K and H1047R) were explored experimentally identifying IRS1 as a binder of E545K mutant protein but not of H1074R mutant protein in pull-down experiments.48 It was also shown that the interaction of E545K mutant PI3Kα with IRS1 is required for the growth of colon cancer cells in vivo.