After autophosphorylation the type 1 insulin-like growth factor receptor (IGF1R) binds and phosphorylates scaffold proteins, IRS1/2/4 and SHC1, which in turn bind effectors possessing enzymatic activity (recently reviewed in Pavelic et al. 2007, Chitnis et al. 2008, Maki et al. 2010, Parrella et al. 2010, and Siddle et al. 2012). IRS1/2/4 can bind both PI3K (via the p85 subunit of PI3K) and the GRB2:SOS complex. PI3K activates PKB (AKT, AKT1) signaling. GRB:SOS stimulates RAS to exchange GDP for GTP leading to activation of RAF and MAPK.